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  • 1001.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Carlsson, G.
    Two senior teachers formulate their professional knowledge. A presentation of a new study with life-history approach1995In: ISATT,1995, 1995Conference paper (Other academic)
  • 1002.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings. Linköping University, Faculty of Educational Sciences.
    Carlsson, G.
    Hartman, S.G.
    Magnusson, Anders
    Linköping University, Department of Behavioural Sciences. Linköping University, Faculty of Arts and Sciences.
    Naeslund, L.
    Rannström, Annika
    Teacher Knowledge Development in a Social and Individual Context1996In: Changing Research and Practice. Teachers' Professionalism, Identities and Knowledge / [ed] Michael Kompf et al., London, Washington: Falmer Press , 1996Chapter in book (Other academic)
  • 1003.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Fahlén, Rose-Marie
    Linköping University, Department of Behavioural Sciences.
    Hjelm, B.
    Nilsson, K.
    Sjögren, J.
    Lathund. Anvisningar för rapportskrivning1994Other (Other (popular science, discussion, etc.))
  • 1004.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Granström, Kjell
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Mixed teams - A ground for pedagogical practice?2000In: Nordic Educational Research Association 28th Congress,2000, 2000Conference paper (Other academic)
  • 1005.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings. Linköping University, Faculty of Educational Sciences.
    Kindgren, Joakim
    Linköping University, Department of Behavioural Sciences. Linköping University, Faculty of Educational Sciences.
    En modell för självvärdering av ämnen inom Filosofiska fakulteten2000In: Undervisning och lŠärande: 4:e universitets pedagogiska konferensenvid Linkšpings universitet16 november 2000 / [ed] Håkan Hult, Linköping: Centrum för universitetspedagogik , 2000, p. 7-10Conference paper (Other (popular science, discussion, etc.))
    Abstract [sv]

    Inom Filosofiska fakulteten arbetar ett kvalitetsutskott i första hand med grundutbildningens utveckling och kvalitet. Kvalitetsutskottet har ett övergripande ansvar att stödja och initiera regelbunden uppföljning och utvärdering inom fakultetens verksamheter samt att initiera och stödja pedagogisk utveckling.

    Som ett led i det långsiktiga kvalitetsarbetet har en rad strategier utvecklats. Bland annat har en databas upprättas för att följa ämnens och programs söktryck, antagning, betygsnivå på. den sist antagne studenten, examination etc. I denna databas finns kvantitativa data om ämnen och program som kontinuerligt uppdateras. För att f. en bild av t ex grundutbildningens forskningsanknytning, internationalisering etc krävs att annan information om program och ämnen samlas in. Här har utskottet valt att pr.va tv. vägar. Programmen utvärderas av en extern utvärderare och ämnena med hjälp av självvärdering.

    En modell för självvärdering har utvecklats och prövas under innevarande termin av tre ämnen på. fakulteten; historia, litteraturvetenskap och bild. Att just dessa tre ämnen har valts ut beror på. att de har olika karaktär och ligger inom olika institutioner. Historia representerar ett traditionellt universitetsämne med l.ng tradition liksom litteraturvetenskap. Båda ligger inom temainstitutionen. Det som skiljer dem åt är att historia har ett stort antal studenter p. A-D nivån och många lärare är verksamma inom ämnet. Litteraturvetenskap är ett något mindre ämne vad gäller antalet studenter och lärare involverade. Bildämnet är inget examensämne på universitet men ingår i flera lärarprogram och ingår också i fristående kursutbudet som fort- och vidareutbildningsmöjlighet. Det ligger p. Estetiska institutionen. Många studenter går kortare kurser i ämnet. För närvarande är få lärare aktiva inom bildämnet.

    Kvalitetsutskottets ambition med självvärderingsmodellen är dels att verka för att ämnena reflekterar över sin situation i relation till ett antal kvalitetsaspekter, dels att ämnena aktivt arbetar med dessa aspekter i ett kontinuerligt utvecklingsarbete. Ett annat syfte är att med hjälp av rapportering från självvärderingarna tillföra fakulteten kunskap om de ämnen som bedriver grundutbildning, kunskaper som förhoppningsvis kan bidra till att beslut om utbildningars dimensionering etc sker p. ett gediget underlag.

    Syftet med presentationen av modellen för självvärderingen under CUP-dagen är att f. diskutera modellen och f. synpunkter för att kunna utveckla modellen vidare. Modellen presenteras kortfattat här. Vid den muntliga presentationen hoppas vi förutom att beskriva modellen också Redovisa de första rapporterna från de ämnen som under hösten prövar modellen.

  • 1006.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Persson, Ulla-Britt
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Lifelong Teacher Learning and Development2000In: European Conference on Educational Research ECER,2000, 2000Conference paper (Other academic)
  • 1007.
    Ahlstrand, Elisabeth
    et al.
    Linköping University, Department of Behavioural Sciences, Teaching and Learning in School, Teacher Education and other Educational Settings. Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Westlund, Ingrid
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning, Teaching and Learning in School, Teacher Education and other Educational Settings.
    Mideklint, Leif
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Fahlén, Lennart
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences.
    Offensiva spelare och coacher i matchen om skolan2007In: Det enkla är det sköna: en vänbok till Kjell Granström / [ed] Einarsson, C, Hammar Chiriac, E, Jedeskog, G, Lindberg, T & Samuelsson, M, Linköping: Skapande vetande , 2007, p. 123-144Chapter in book (Other academic)
    Abstract [sv]

    Om språkutveckling / Jan Anward -- Forskningsmiljöer och seminariekulturer : ideal och verklighet / Gunnar Berg -- Gruppens obönhörliga brist på demokrati / Gunnel Colnerud -- Undervisningsspråket : en del av lärares yrkesspråk / Anna-Lena Eriksson Gustavsson, Rose-Marie Fahlén, Ulla-Britt Persson & Joakim Samuelsson -- Dialogism and social constructivism / Per Linell -- Samhällsaktiva skolor och skolaktiva samhällen i glesbygd : utopi eller möjlighet? / Annika Andræ Thelin -- Användningen av tiden i skolan / Mats Ekholm -- Offensiva spelare och coacher i matchen om skolan / Lennart Fahlén, Elisabeth Ahlstrand, Ingrid Westlund & Leif Mideklint -- Analyser av skolors anda / Rolf Lander -- Samhällsförändring, skolprofilering och identitet / Lars Naeslund & Jens Pedersen -- Succession and managing the transition from predecessor to successor / Siv Boalt Boëthius -- Freud som gruppsykolog : en orättvis betraktelse till 150-årsdagen / Stefan Jern -- Gruppens känslomässiga klimat / Eric Olsson -- Från Göteborg till Dortmund : studier i masshändelser / Michael Rosander & Ingrid Hylander -- Gruppetenking og operativ effektivitet i team / Endre Sjøvold -- Existens och relationer / Dan Stiwne -- Är det bra att vara ambitiös? / Viveka Adelswärd och Johan Hofvendahl -- Ja, för jag är så jävla snygg!" : retsekvenser och informellt lärande i högstadiets grupparbeten / Karin Aronsson & Michael Tholander -- Skolpsykolog : beprövad erfarenhet och specialitet på vetenskaplig grund? / Gunilla Guvå & Ingrid Hylander -- Slump, sammanträffanden och spår : om en lärares inflytande / Stefan Jern & Anders Hempel -- Villkor för psykologisk forskning : hur de statliga forskningsråden fördelade sina pengar inom psykologiområdet 1996-98 / Rolf Sandell och Kjell Granström -- Urval publikationer Kjell Granström. Svensk engelsk och norsk text.

  • 1008.
    Ahlstrand, I
    et al.
    Jönköping University.
    Thyberg, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences.
    Falkmer, T
    Curtin University, Perth, Australia.
    Björk, M
    OP0209-HPR Less Pain and Activity Limitations in Today's Early RA Patients Compared with Patients Diagnosed 10 Years Earlier (The Swedish Tira-Project)2014Conference paper (Refereed)
    Abstract [en]

    Background: Over the last decades the RA-treatment strategies have changed considerably. Routines for early RA diagnosis and instituted disease modifying anti rheumatic drugs (DMARDs) have been established. In the early 2000s biologic agents also became available for treatment purposes. Despite these altered and improved strategies RA patients continue to report pain and activity limitations; women more so than men.Objectives: To study differences regarding pain and activity limitations during the first three years after diagnosis of RA in today's patients compared with patients diagnosed 10 years earlier from a gender perspective.Methods: This study was based on patients recruited to the project “early interventions in RA” (TIRA). In the first cohort (TIRA-1) 320 patients were included during 1996-1998. In the second cohort (TIRA-2) 463 patients were included during 2006-2008. Disease activity score 28 joint count (DAS-28) and medication were registered. Pain intensity (VAS), bodily pain (BP) in Short Form36 (SF-36) and activity limitation (Health Assessment Questionnaire, HAQ) were reported at inclusion and at follow-ups after one, two and three years.Results: Disease activity did not differ between cohorts at inclusion, but was significant lower at the follow ups in the TIRA-2 cohort compared with the TIRA-1 cohort. Patients in TIRA2 were prescribed traditional DMARD:s and biologic agents more frequent than in TIRA-1. The TIRA-2 patients reported significantly higher pain intensity and activity limitations at inclusion but lower pain intensity and activity limitations at all follow-ups than TIRA-1 patients. There were no significant differences between cohorts regarding bodily pain at inclusion, but thereafter the TIRA-2 patients showed significant lower bodily pain than the TIRA-1 patients. Men reported lower activity limitation than women in TIRA-1; otherwise there were no gender differences in TIRA-1. In TIRA-2, there were no significant gender differences regarding pain at inclusion. However, men reported lower pain than women at all follow-ups. Women, in turn, reported significantly higher activity limitations at all time points in TIRA-2. Pain and activity limitations were significantly reduced from inclusion to the one year follow-up but remained stable thereafter.Conclusions: Both women and men in today's early RA patient cohort report lower pain and less activity limitations at the follow ups after diagnosis of RA compared to 10 years earlier. However, both activity limitations and bodily pain are still pronounced.Disclosure of Interest: None declared

  • 1009.
    Ahlstrand, I.
    et al.
    School of Health Sciences, Jönköping University, Jönköping, Sweden.
    Thyberg, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Rheumatology.
    Falkmer, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. School of Health Sciences, Jönköping University, Jönköping, Sweden; School of Occupational Therapy and Social Work, CHIRI, Curtin University, Perth, WA, Australia.
    Dahlström, Örjan
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Björk, Mathilda
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Rehabilitation Center. School of Health Sciences, Jönköping University, Jönköping, Sweden.
    Pain and activity limitations in women and men with contemporary treated early RA compared to 10 years ago: the Swedish TIRA project2015In: Scandinavian Journal of Rheumatology, ISSN 0300-9742, E-ISSN 1502-7732, Vol. 44, no 4, p. 259-264Article in journal (Refereed)
    Abstract [en]

    Objectives: To study differences regarding pain and activity limitations during the 3 years following diagnosis in women and men with contemporary treated early RA compared with their counterparts who were diagnosed 10 years earlier. Method: This study was based on patients recruited to the Early Intervention in RA (TIRA) project. In the first cohort (TIRA-1) 320 patients were included in time for diagnosis during 1996-1998 and 463 patients were included in the second cohort (TIRA-2) during 2006-2009. Disease activity, pain intensity (Visual Analogue Scale, VAS), bodily pain (BP) in the 36-item Short Form Health Survey (SF-36), activity limitations (Health Assessment Questionnaire, HAQ), and medication were reported at inclusion and at follow-up after 1, 2, and 3 years. Results: Disease activity, pain, and activity limitations were pronounced at inclusion across both genders and in both cohorts, with some improvement observed during the first year after diagnosis. Disease activity did not differ between cohorts at inclusion but was significantly lower at the follow-ups in the TIRA-2 cohort, in which the patients were prescribed traditional disease-modifying anti-rheumatic drugs (DMARDs) and biological agents more frequently. In TIRA-2, patients reported significantly lower pain and activity limitations at all follow-ups, with men reporting lower pain than women. Women reported significantly higher activity limitations at all time points in TIRA-2. Conclusions: Pain and activity limitations were still pronounced in the contemporary treated early RA cohort compared with their counterparts diagnosed 10 years earlier and both of these factors need to be addressed in clinical settings.

  • 1010.
    Ahlstrand, Inger
    et al.
    ADULT, HHJ, Hälsohögskolan, Högskolan i Jönköping.
    Björk, Mathilda
    Avd. för rehabilitering, HHJ, Hälsohögskolan, Högskolan i Jönköping.
    Thyberg, Ingrid
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Rheumatology.
    Börsbo, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Falkmer, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Habilitation in Central County.
    Pain and daily activities in Rheumatoid Arthritis2012In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 34, no 15, p. 1245-1253Article in journal (Refereed)
    Abstract [en]

    Aim: The aim of this study was to describe experiences of pain and its relationship to daily activities in people with rheumatoid arthritis (RA). Method: Seven semi-structured focus group discussions were conducted with 33 men and women of different ages with RA. Data were analysed with content analysis. Results: Pain affected everyday life and may be a barrier to perform valued activities. Regarding the impact of pain on participation and independence, personal factors and the social environment were found to be important. It could be a struggle to find the right activity balance, since it was easy to be overactive, triggering subsequent elevation of pain levels. However, the participants also described activities as a mediator of pain and a distraction from it. Conclusion: The relationship between pain and daily activities in RA was complex. Pain as an impairment was expressed to be related to activity limitations and participation restrictions, as well as to contextual factors. These findings highlight the clinical importance of paying attention to the complexity of pain and its relation to daily activities and participation.

  • 1011.
    Ahlstrand, Inger
    et al.
    Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för rehabilitering.
    Björk, Mathilda
    Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för rehabilitering.
    Thyberg, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Börsbo, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Falkmer, Torbjörn
    Hälsohögskolan, Högskolan i Jönköping, HHJ, Avd. för rehabilitering.
    Smärta och dagliga aktiviteter vid Reumatoid artrit ur ett patientperspektiv2011Conference paper (Other academic)
    Abstract [sv]

    Bakgrund: Smärta vid Reumatoid artrit (RA) ärett välkänt symtom som orsakar lidande ochaktivitetsbegränsning. Traditionellt mäts smärtainom reumatologin som smärtintensitet på enVisuell Analog Skala (VAS). Kunskapen kring hurpatienter med RA upplever smärta och dess konsekvenser är begränsad. Patientens egenbeskrivning behövs som underlag för behandlingsplanering och för att utveckla nya metoderför att beskriva problematiken.Syfte: Syftet med studien är att beskriva smärtavid RA ur ett patientperspektiv med fokus på hursmärtan påverkar dagliga aktiviteter.Metod: Patienter med diagnostiserad RA i syd-östra Sverige identifierades via Svenska Reumatologiregistret. Urvalet baserades på minst 5 årssjukdomsduration och minst 40 mm smärtintensitet på VAS vid de två senaste besöken på reumatologklinik. Sammanlagt 33 patienter, 7 män och26 kvinnor, deltog i sju fokusgrupper. Gruppernaformades utifrån kön och ålder. Intervjuguideninnehöll frågor som: Hur beskriver patienter medRA sin smärta? Vad påverkar smärtan? Vilkakonsekvenser har smärtan för aktivitetsutförande,aktivitetsbalans och undvikande av aktivitet? Enkvalitativ innehållsanalys görs.Resultat/förväntat resultat: Analyser hittills visar patienternas frustration över att inteklara det man vill eller behöver göra, beroendeav andra, minskade möjligheter till delaktigheti sociala sammanhang. Och närståendes betydelse. Analyserna visar att smärtan är relaterad till Göteborg6-8 april 201134trötthet, stress och sinnesstämning och att arbeteeller andra aktiviteter medverkar till att glömmabort smärtan och uppehålla förmåga. Analysenslutförs under hösten.Konklusion: Denna studie förväntas genererany angelägen kunskap om och förståelse försmärta.

  • 1012.
    Ahlstrand, Inger
    et al.
    Jonköping University, Sweden.
    Björk, Mathilda
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Rehabilitation Center. Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Jonköping University, Sweden.
    Thyberg, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Rheumatology.
    Falkmer, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Jonköping University, Sweden; Curtin University, Australia.
    Pain and difficulties performing valued life activities in women and men with rheumatoid arthritis2015In: Clinical Rheumatology, ISSN 0770-3198, E-ISSN 1434-9949, Vol. 34, no 8, p. 1353-1362Article in journal (Refereed)
    Abstract [en]

    This study aimed to examine the difficulties with performing valued life activities in relation to pain intensity in women and men with rheumatoid arthritis (RA). In total, 737 persons with RA (73 % women) from three rheumatology units in Sweden responded to a questionnaire measuring performance of 33 valued life activities and self-rated pain. The relationships between performance of valued life activities (VLAs) and pain (measured by visual analogue scale (VAS)) were analysed based on gender. Multiple linear regression analyses were conducted with the total VLA score as dependent variable. Women reported more pain and difficulties in performing valued life activities than men. Across genders, 85 % reported at least one valued life activity affected by RA. Significantly more women than men encountered difficulties in performing some activities such as cooking, gardening and meeting new people. Women reported higher pain intensity (35 mm) than men (31 mm). Almost all 33 difficulty ratings for valued life activities were higher among persons with high pain (greater than 40 mm) than persons with lower pain. Difficulty ratings for valued life activities correlated positively with pain in persons with lower pain, but not among those with high pain. The results highlight the importance of addressing pain, especially among women with RA, as they reported pain to impact on their valued life activities. Interestingly, this was evident also in women with lower levels of pain.

  • 1013.
    Ahlstrand, Inger
    et al.
    School of Health and Welfare, Jönköping University, Jönköping, Sweden.
    Vaz, Sharmila
    School of Occupational Therapy & Social Work, CHIRI, Curtin University, Perth, WA, Australia.
    Falkmer, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. School of Health and Welfare, Jönköping University, Jönköping, Sweden.
    Thyberg, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Rheumatology.
    Björk, Mathilda
    Linköping University, Department of Social and Welfare Studies, Division of Occupational Therapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Rheumatology.
    Self-efficacy and pain acceptance as mediators of the relationship between pain and performance of valued life activities in women and men with rheumatoid arthritis2017In: Clinical Rehabilitation, ISSN 0269-2155, E-ISSN 1477-0873, Vol. 31, no 6, p. 824-834Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To study whether personal factors (self-efficacy and pain acceptance) mediate the relationship between pain and performance of valued life activities in persons with rheumatoid arthritis.

    METHODS: Persons with rheumatoid arthritis for at least four years (n = 737; 73% women) answered a questionnaire measuring self-efficacy, pain acceptance, performance of valued life activities, and self-rated pain. Relationships among these constructs were explored using univariate and multivariate analyses. Structural equation modelling was then used to examine the mediational role of personal factors on the relationship between pain and performance of valued life activities.

    RESULTS: A direct negative association between pain and performance of valued life activities was identified (Beta = .34, P < .001). This suggests that people with rheumatoid arthritis who had higher levels of pain has increased difficulties in performing valued life activities. Self-efficacy and activity engagement component of pain acceptance mediated the relationship between pain and performance of valued life activities, however the pain willingness component of pain acceptance did not influence participation in valued life activities.

    CONCLUSION: These findings highlight the importance of considering personal factors, such as pain acceptance and self-efficacy, in facilitating participation in valued life activities.

  • 1014.
    Ahlstrand, Pernilla
    Linköping University, Department of Behavioural Sciences and Learning.
    "De famlar i mörkret"...: en studie om bedömning inom den praktiska kunskapstraditionen.2009Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I den kvalitativa studien undersöks vad som ligger till grund för bedömning i fyra ämnen inom gymnasieskolan. De ämnen som undersöks är teater, idrott- och hälsa, hotel- och restaurang samt träteknik. Intervjuer med lärare visar att det läggs stor vikt vid bedömning av processen i den dagliga undervisningen, dvs. närvaro, samarbete, ansvar, behov av handledning, självständighet och ambition. Även den produkt eller det slutresultat som undervisningen leder fram till tas med i bedömningen. Lärarna uttrycker även att teoretiska aspekter på undervisningen såsom faktakunskaper, analys, att problematisera och reflektera är underlag för bedömning. Personlig färdighet, talang, förkunskaper samt att kunna göra kopplingar till yrket dvs. elevens förmåga att tillämpa sina kunskaper väger även det in i bedömningen. Observationer vid omdömessamtal samt analys av skriftliga omdömen visar att det är processen som får mest utrymme i bedömningen. För att dokumentera och avgöra om eleven nått målen för undervisningen använder sig lärarna av anteckningar men även den produkt eller det resultat som består. Lärarna beskriver även att de genom kommunikation med eleverna och genom att uppmärksamma hur elever reflekterar kring uppgifterna gör bedömningar. Lärarna uttrycker att de skulle önska att de kunde arbeta mer med bedömning men det som hindrar de är fram för allt tiden, att man upplever att man i så fall skulle behöva strukturera om eller göra avkall på viss undervisning. Andra hinder som lärarna beskriver är att man är fast i vissa traditioner vad gäller undervisning och organisation. Dessutom beskriver lärarna att de saknar tydlighet hur de själva kommunicerar mål och betygskriterier till eleverna.

  • 1015.
    Ahlstrand, Pernilla
    Linköping University, Department of Behavioural Sciences and Learning.
    Vad är estetiskt lärande? Från empiri till teori2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Den här studien undersöker ett estetiskt lärande kopplat till estetiska programmet inom gymnasieskolan. En undersökning, baserad på triangulering är gjord. Syftet är att vaska fram elever och lärares tankar om estetiskt lärande och därigenom skapa kategorier. Enkät, intervju och loggböcker har analyserats för att ringa in hur en estetisk läroprocess kan definieras. Data har analyserats genom en fenomenografisk analysmetod för att på så sätt synliggöra människors olika uppfattningar. Utifrån kategorierna har framkommit sex

    begrepp: kunskap, personlig utveckling, praktisk kunskap, samarbete, motivation och scenisk närvaro. Med hjälp av begreppen analyseras forskning och litteratur med syfte att förankra begreppen teoretiskt. Den praktiska kunskapen speglas i ett teoretiskt språk för att visa på kopplingen mellan teori och praktik.

    Studien landar i ett sociokulturellt förhållningssätt där likheter dras mellan ett sociokulturellt lärande och en estetisk läroprocess.

  • 1016.
    Ahlstrand, Pia
    et al.
    Linköping University, Department of Social and Welfare Studies.
    Bjärle, Karin
    Linköping University, Department of Social and Welfare Studies.
    Har utlandsadopterade barn språkproblem?: En undersökning om vad föräldrar och pedagoger anser2006Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Syftet med denna uppsats var att undersöka hur stor kunskap pedagoger har om utlandsadopterade barn och deras eventuella språkproblem. De frågeställningar vi ämnade besvara var bland annat vad litteraturen skriver om utlandsadopterade barns språk. Vi ville också ta reda på vad föräldrarna till de utlandsadopterade barnen hade för åsikter om deras barns eventuella språkproblem och hur dessa barnen fått den hjälp de rimligtvis behöver. Vi arbetade enligt trianguleringsmetoden och arbetet inleds med en litteraturstudie, där vi redogör för den forskning vi tagit del av. Därefter följer en enkätundersökning där 15 föräldrar till utlandsadopterade barn deltog. Metoddelen avslutas med intervjuer av fem pedagoger. Resultatet visar att föräldrarna, efter hårt arbete, fick den hjälp som barnet behövde, exempelvis genom att få hjälp av en logoped eller talpedagog. Resultatet visar även att lärarna i vår undersökning inte hade någon större kunskap om utlandsadopterade barns språkproblem.

  • 1017.
    Ahlstrand, Sandra
    et al.
    Linköping University, Department of Thematic Studies.
    Berglund, Linda
    Linköping University, Department of Thematic Studies.
    Det Nya Sydafrika: Nationell identitet och bygget av en regnbågsnation2003Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [en]

    The South African nation and society have experienced significant changes and reforms over the last decade. Less than ten years ago black and white people were not even allowed to share a bench in a park. Today they are expected to live side by side in what is called a"Rainbow Nation". When a new society is built language plays an important part. The language constantly reproduces daily the small things that identify a nation and the people living in it. Language creates and reproduces truths. Creates stereotypes, thoughts. It creates emotions.

    In this thesis we discuss how nation building depicts in the South African newspapers. The representation of the South African nation and people is analysed through concrete examples. But we also emphasise a situation in society that not only concerns South Africa, but many other countries in the world. As immigration merges ethnically homogeneous nations, it forces people to reflect upon themselves and what national identity they belong to.

  • 1018.
    Ahlstrom, Christer
    et al.
    Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    Anund, Anna
    Not Found:Linkoping Univ, Rehabil Med, Linkoping, Sweden; Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    Fors, Carina
    Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    Akerstedt, Torbjorn
    Stockholm Univ, Sweden; Karolinska Inst, Sweden.
    The effect of daylight versus darkness on driver sleepiness: a driving simulator study2018In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 27, no 3, article id UNSP e12642Article in journal (Refereed)
    Abstract [en]

    Driver sleepiness studies are often carried out with alert drivers during daytime and sleep-deprived drivers during night-time. This design results in a mixture of different factors (e.g. circadian effects, homeostatic effects, light conditions) that may confound the results. The aim of this study was to investigate the effect of light conditions on driver sleepiness. Thirty young male drivers (23.6 +/- 1.7years old) participated in a driving simulator experiment where they drove on a rural road. A 2x2 design was used with the conditions daylight versus darkness, and daytime (full sleep) versus night-time (sleep deprived). The results show that light condition had an independent effect on the sleepiness variables. The subjective sleepiness measured by Karolinska Sleepiness Scale was higher, lateral position more left-oriented, speed lower, electroencephalogram alpha and theta higher, and blink durations were longer during darkness. The number of line crossings did not change significantly with light condition. The day/night condition had profound effects on most sleepiness indicators while controlling for light condition. The number of line crossings was higher during night driving, Karolinska Sleepiness Scale was higher, blink durations were longer and speed was lower. There were no significant interactions, indicating that light conditions have an additive effect on sleepiness. In conclusion, Karolinska Sleepiness Scale and blink durations increase primarily with sleep deprivation, but also as an effect of darkness. Line crossings are mainly driven by the need for sleep and the reduced alertness at the circadian nadir. Lane position is, however, more determined by light conditions than by sleepiness.

  • 1019.
    Ahlstrom, Christer
    et al.
    Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    Lovgren, Maria Gink
    Volvo Bus Corp, Denmark.
    Nilsson, Mats
    Volvo Bus Corp, Denmark.
    Willstrand, Tania Dukic
    Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    Anund, Anna
    Not Found:Linkoping Univ, Rehabil Med, Linkoping, Sweden; Swedish Natl Rd and Transport Res Inst VTI, Linkoping, Sweden.
    The effect of an active steering system on city bus drivers muscle activity2019In: International Journal of Occupational Safety and Ergonomics, ISSN 1080-3548, E-ISSN 2376-9130, Vol. 25, no 3, p. 377-385Article in journal (Refereed)
    Abstract [en]

    City bus drivers spend hours driving under time pressure, in congested traffic and in a monotonous sitting position. This leads to unhealthy working conditions, especially in terms of physical and psychological stress. The aim of this study is to investigate whether an active steering system can alleviate the musculoskeletal stress involved in manoeuvring a bus. Twenty bus drivers drove a city bus equipped with the Volvo dynamic steering (VDS) support system in real traffic. Steering effort was evaluated with electromyography and with a questionnaire. Compared to baseline, VDS significantly reduced the required muscle activity by on average 15-25% while turning, and up to 68% in the part of the manoeuvre requiring maximum effort. The bus drivers believed that VDS will help reduce neck and shoulder problems, and they expressed a desire to have VDS installed in their own bus.

  • 1020.
    Ahlstrom, Christina A.
    et al.
    US Geol Survey, AK 99508 USA.
    Bonnedahl, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Kalmar Cty Hosp, Sweden.
    Woksepp, Hanna
    Kalmar Cty Hosp, Sweden.
    Hernandez, Jorge
    Uppsala Univ, Sweden.
    Olsen, Bjorn
    Uppsala Univ, Sweden.
    Ramey, Andrew M.
    US Geol Survey, AK 99508 USA.
    Acquisition and dissemination of cephalosporin-resistant E.coli in migratory birds sampled at an Alaska landfill as inferred through genomic analysis2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 7361Article in journal (Refereed)
    Abstract [en]

    Antimicrobial resistance (AMR) in bacterial pathogens threatens global health, though the spread of AMR bacteria and AMR genes between humans, animals, and the environment is still largely unknown. Here, we investigated the role of wild birds in the epidemiology of AMR Escherichia coli. Using next-generation sequencing, we characterized cephalosporin-resistant E. coli cultured from sympatric gulls and bald eagles inhabiting a landfill habitat in Alaska to identify genetic determinants conferring AMR, explore potential transmission pathways of AMR bacteria and genes at this site, and investigate how their genetic diversity compares to isolates reported in other taxa. We found genetically diverse E. coli isolates with sequence types previously associated with human infections and resistance genes of clinical importance, including blaCTX-M and blaCMY. Identical resistance profiles were observed in genetically unrelated E. coli isolates from both gulls and bald eagles. Conversely, isolates with indistinguishable core-genomes were found to have different resistance profiles. Our findings support complex epidemiological interactions including bacterial strain sharing between gulls and bald eagles and horizontal gene transfer among E. coli harboured by birds. Results suggest that landfills may serve as a source for AMR acquisition and/or maintenance, including bacterial sequence types and AMR genes relevant to human health.

  • 1021.
    Ahlstrom, Christina A.
    et al.
    US Geol Survey, AK 99508 USA.
    Bonnedahl, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences. Kalmar Cty Council, Sweden.
    Woksepp, Hanna
    Kalmar Cty Hosp, Sweden.
    Hernandez, Jorge
    Kalmar Cty Hosp, Sweden.
    Reed, John A.
    US Geol Survey, AK 99508 USA.
    Tibbitts, Lee
    US Geol Survey, AK 99508 USA.
    Olsen, Bjoern
    Uppsala Univ, Sweden.
    Douglas, David C.
    US Geol Survey, AK USA.
    Ramey, Andrew M.
    US Geol Survey, AK 99508 USA.
    Satellite tracking of gulls and genomic characterization of faecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial-resistant Escherichia coli on the Kenai Peninsula, Alaska2019In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 28, no 10, p. 2531-2545Article in journal (Refereed)
    Abstract [en]

    Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well described. We equipped 17 landfill-foraging gulls with satellite transmitters and collected gull faecal samples longitudinally from four locations on the Kenai Peninsula, Alaska to assess: (a) gull attendance and transitions between sites, (b) spatiotemporal prevalence of faecally shed AMR E. coli, and (c) genomic relatedness of AMR E. coli isolates among sites. We also sampled Pacific salmon (Oncorhynchus spp.) harvested as part of personal-use dipnet fisheries at two sites to assess potential contamination with AMR E. coli. Among our study sites, marked gulls most commonly occupied the lower Kenai River (61% of site locations) followed by the Soldotna landfill (11%), lower Kasilof River (5%) and upper Kenai River (amp;lt;1%). Gulls primarily moved between the Soldotna landfill and the lower Kenai River (94% of transitions among sites), which were also the two locations with the highest prevalence of AMR E. coli. There was relatively high spatial and temporal variability in AMR E. coli prevalence in gull faeces and there was no evidence of contamination on salmon harvested in personal-use fisheries. We identified E. coli sequence types and AMR genes of clinical importance, with some isolates possessing genes associated with resistance to as many as eight antibiotic classes. Our findings suggest that gulls acquire AMR E. coli at habitats with anthropogenic inputs and subsequent movements may represent pathways through which AMR is dispersed.

  • 1022.
    Ahlstrom, Christina A.
    et al.
    US Geol Survey, AK 99508 USA.
    Ramey, Andrew M.
    US Geol Survey, AK 99508 USA.
    Woksepp, Hanna
    Kalmar Council, Sweden.
    Bonnedahl, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences. Kalmar Council, Sweden.
    Early emergence of mcr-1-positive Enterobacteriaceae in gulls from Spain and Portugal2019In: Environmental Microbiology Reports, ISSN 1758-2229, E-ISSN 1758-2229Article in journal (Refereed)
    Abstract [en]

    We tested extended-spectrum beta-lactamase producing bacteria from wild gulls (Larus spp.) sampled in 2009 for the presence of mcr-1. We report the detection of mcr-1 and describe genome characteristics of four Escherichia coli and one Klebsiella pneumoniae isolate from Spain and Portugal that also exhibited colistin resistance. Results represent the earliest evidence for colistin-resistant bacteria in European wildlife.

  • 1023.
    Ahlstrom, Christina A.
    et al.
    US Geol Survey, AK 99508 USA.
    Ramey, Andrew M.
    US Geol Survey, AK 99508 USA.
    Woksepp, Hanna
    Dept Dev and Publ and Hlth, Sweden.
    Bonnedahl, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology, Infection and Inflammation. Linköping University, Faculty of Medicine and Health Sciences. Dept Infect Dis, Sweden.
    Repeated Detection of Carbapenemase-Producing Escherichia coil in Gulls Inhabiting Alaska2019In: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 63, no 8, article id e00758-19Article in journal (Refereed)
    Abstract [en]

    Here, we report the first detection of carbapenemase-producing Escherichia coli in Alaska and in wildlife in the United States. Wild bird (gull) feces sampled at three locations in Southcentral Alaska yielded isolates that harbored plasmidencoded bla(kpc-2), or chromosomally encoded bla(OXA-48) and genes associated with antimicrobial resistance to up to eight antibiotic classes.

  • 1024.
    Ahlstrom, G.
    et al.
    Ahlström, G., Department of Health Sciences, University of Örebro, SE-701 82 Örebro, Sweden.
    Lindvall, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurology . Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Wenneberg, S.
    Department of Health Sciences, University of Örebro, SE-701 82 Örebro, Sweden.
    Gunnarsson, L.G.
    Department of Neurology and Neurophysiology, Örebro University Hospital, Örebro, Sweden.
    A comprehensive rehabilitation programme tailored to the needs of adults with muscular dystrophy2006In: Clinical Rehabilitation, ISSN 0269-2155, E-ISSN 1477-0873, Vol. 20, no 2, p. 132-141Article in journal (Refereed)
    Abstract [en]

    Objective: To assess if activities of daily living (ADL), coping and quality of life could be improved in adults with muscular dystrophy through a comprehensive rehabilitation programme. Design: Quasi-experimental, controlled clinical study comparing patients with similar age and disease aspects. Setting: Two different counties in Sweden, being either study or control setting. Subjects: The study group comprised 37 adults (21 women, 16 men, mean age 50 years), while the control group comprised 39 people (25 women, 14 men, mean age 46 years). Interventions: Four rehabilitation sessions tailored to different medical, physical and psychosocial needs of the patients, comprising a total of 10 days over a period of 18 months. Main measures: ADL, the Mental Adjustment to Cancer Scale measuring coping strategies, the Sickness Impact Profile measuring health-related quality of life, the Hospital Anxiety and Depression Scale, and the Psychosocial Well-being Questionnaire. Results: No significant differences were found between groups with regard to the outcome measures. There was increased dependence on others in ADL after 18 months in both groups, but it was more pronounced in the control group. Furthermore, a clear trend was observed in the data with regard to coping patterns, the control group using more coping strategies such as 'Helplessness/hopelessness' (P = 0.057), 'Anxious preoccupation' (P = 0.085) and 'Fatalistic' (P = 0.073) when being compared to the study group. Conclusions: No apparent effects on ADL were found from the rehabilitation programme, although there was a tendency of reduction of maladaptive coping patterns in the study group. This initial study may provide the rationale and basis for a randomized controlled trial. © 2006 Edward Arnold (Publishers) Ltd.

  • 1025.
    Ahlstrom, Gerd
    et al.
    Lund Univ, Sweden.
    Nilsen, Per
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Benzein, Eva
    Linnaeus Univ, Sweden.
    Behm, Lina
    Lund Univ, Sweden.
    Wallerstedt, Birgitta
    Linnaeus Univ, Sweden.
    Persson, Magnus
    Lund Univ, Sweden.
    Sandgren, Anna
    Linnaeus Univ, Sweden.
    Implementation of knowledge-based palliative care in nursing homes and pre-post post evaluation by cross-over design: a study protocol2018In: BMC Palliative Care, ISSN 1472-684X, E-ISSN 1472-684X, Vol. 17, article id 52Article in journal (Refereed)
    Abstract [en]

    Background: The demography of the world is changing as the population is ageing. Because of this change to a higher proportion of older people, the WHO has called for improved palliative care for older persons. A large number of all deaths in the industrialised world occur while older people are living in nursing homes and therefore a key question becomes how the principles of palliative care can be implemented in that context. The aims of this study are: a) to describe a model of an educational intervention with the goal of implementing knowledge-based palliative care in nursing homes, and b) to describe the design of the evaluation of the effectiveness regarding the implementation of knowledge-based palliative care. Methods/design: A complex intervention is evaluated by means of a cross-over design. An educational intervention concerning palliative care consisting of five seminars during 6 months for staff and managers has been developed and conducted in 20 nursing homes in two counties. Before the intervention started, the feasibility was tested in a pilot study conducted in nursing homes not included in the main study. The intervention is evaluated through a non-randomized experimental design with intervention and control groups and pre- and post-assessments. The evaluation includes older persons living in nursing homes, next-of-kin, staff and managers. Data collection consists of quantitative methods such as questionnaires and register data and qualitative methods in the form of individual interviews, focus-group interviews and participant observations. Discussion: The research will contribute to new knowledge about how to implement knowledge-based palliative care in a nursing home setting. A strength of this project is that the Medical Research Council framework of complex intervention is applied. The four recommended stages, Development, Feasibility and piloting, Evaluation and Implementation, are combined for the educational intervention, which functions as a strategy to achieve knowledge-based palliative care in the nursing homes. Implementation is always a question of change and a good theoretical understanding is needed for drawing valid conclusions about the causal mechanisms of change. The topic is highly relevant considering the worlds ageing population. The data collection is completed and the analysis is ongoing.

  • 1026.
    Ahlström, Christer
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Nonlinear phonocardiographic Signal Processing2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis work has been to develop signal analysis methods for a computerized cardiac auscultation system, the intelligent stethoscope. In particular, the work focuses on classification and interpretation of features derived from the phonocardiographic (PCG) signal by using advanced signal processing techniques.

    The PCG signal is traditionally analyzed and characterized by morphological properties in the time domain, by spectral properties in the frequency domain or by nonstationary properties in a joint time-frequency domain. The main contribution of this thesis has been to introduce nonlinear analysis techniques based on dynamical systems theory to extract more information from the PCG signal. Especially, Takens' delay embedding theorem has been used to reconstruct the underlying system's state space based on the measured PCG signal. This processing step provides a geometrical interpretation of the dynamics of the signal, whose structure can be utilized for both system characterization and classification as well as for signal processing tasks such as detection and prediction. In this thesis, the PCG signal's structure in state space has been exploited in several applications. Change detection based on recurrence time statistics was used in combination with nonlinear prediction to remove obscuring heart sounds from lung sound recordings in healthy test subjects. Sample entropy and mutual information were used to assess the severity of aortic stenosis (AS) as well as mitral insufficiency (MI) in dogs. A large number of, partly nonlinear, features was extracted and used for distinguishing innocent murmurs from murmurs caused by AS or MI in patients with probable valve disease. Finally, novel work related to very accurate localization of the first heart sound by means of ECG-gated ensemble averaging was conducted. In general, the presented nonlinear processing techniques have shown considerably improved results in comparison with other PCG based techniques.

    In modern health care, auscultation has found its main role in primary or in home health care, when deciding if special care and more extensive examinations are required. Making a decision based on auscultation is however difficult, why a simple tool able to screen and assess murmurs would be both time- and cost-saving while relieving many patients from needless anxiety. In the emerging field of telemedicine and home care, an intelligent stethoscope with decision support abilities would be of great value.

    List of papers
    1. A method for accurate localization of the first heart sound and possible applications
    Open this publication in new window or tab >>A method for accurate localization of the first heart sound and possible applications
    2008 (English)In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 29, no 3, p. 417-428Article in journal (Refereed) Published
    Abstract [en]

    We have previously developed a method for localization of the first heart sound (S1) using wavelet denoising and ECG-gated peak-picking. In this study, an additional enhancement step based on cross-correlation and ECG-gated ensemble averaging (EA) is presented. The main objective of the improved method was to localize S1 with very high temporal accuracy in (pseudo-) real time. The performance of S1 detection and localization, with and without EA enhancement, was evaluated on simulated as well as experimental data. The simulation study showed that EA enhancement reduced the localization error considerably and that S1 could be accurately localized at much lower signal-to-noise ratios. The experimental data were taken from ten healthy subjects at rest and during invoked hyper- and hypotension. For this material, the number of correct S1 detections increased from 91% to 98% when using EA enhancement. Improved performance was also demonstrated when EA enhancement was used for continuous tracking of blood pressure changes and for respiration monitoring via the electromechanical activation time. These are two typical applications where accurate localization of S1 is essential for the results.

    Place, publisher, year, edition, pages
    Institutionen för medicinsk teknik, 2008
    Keywords
    ensemble averaging, detection, localization, heart sound, bioacoustics
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-11856 (URN)10.1088/0967-3334/29/3/011 (DOI)
    Note
    Original publication: C Ahlstrom, T Länne, P Ask and A Johansson, A method for accurate localization of the first heart sound and possible applications, 2008, Physiological Measurement, (29), 3, 417-428. http://dx.doi.org/10.1088/0967-3334/29/3/011. Copyright: Institute of Physics and IOP Publishing Limited, http://www.iop.org/EJ/journal/PMAvailable from: 2008-05-20 Created: 2008-05-20 Last updated: 2017-12-13
    2. Assessing Aortic Stenosis using Sample Entropy of the Phonocardiographic Signal in Dogs
    Open this publication in new window or tab >>Assessing Aortic Stenosis using Sample Entropy of the Phonocardiographic Signal in Dogs
    Show others...
    2008 (English)In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 55, no 8, p. 2107-2109Article in journal (Refereed) Published
    Abstract [en]

    In aortic valve stenosis (AS), heart murmurs arise as an effect of turbulent blood flow distal to the obstructed valves. With increasing AS severity, the flow becomes more unstable, and the ensuing murmur becomes more complex. We hypothesize that these hemodynamic flow changes can be quantified based on the complexity of the phonocardiographic (PCG) signal. In this study, sample entropy (SampEn) was investigated as a measure of complexity using a dog model. Twenty-seven boxer dogs with various degrees of AS were examined with Doppler echocardiography, and the peak aortic flow velocity (Vmax) was used as a reference of AS severity. SampEn correlated to Vmax with R = 0.70 using logarithmic regression. In a separate analysis, significant differences were found between physiologic murmurs and murmurs caused by AS (p < 0.05), and the area under a receiver operating characteristic curve was calculated to 0.96. Comparison with previously presented PCG measures for AS assessment showed improved performance when using SampEn, especially for differentiation between physiological murmurs and murmurs caused by mild AS. Studies in patients will be needed to properly assess the technique in humans.

    Keywords
    Aortic stenosis (AS), bioacoustics, heart sound, murmur, sample entropy (SampEn)
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13042 (URN)10.1109/TBME.2008.923767 (DOI)
    Available from: 2008-03-20 Created: 2008-03-20 Last updated: 2017-12-13
    3. Assessing mitral regurgitation attributable to myxomatous mitral valve disease in dogs using signal analysis of heart sounds and murmurs
    Open this publication in new window or tab >>Assessing mitral regurgitation attributable to myxomatous mitral valve disease in dogs using signal analysis of heart sounds and murmurs
    Show others...
    2008 (English)Article in journal (Refereed) Submitted
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13043 (URN)
    Available from: 2008-03-20 Created: 2008-03-20 Last updated: 2009-03-26
    4. Feature Extraction for Systolic Heart Murmur Classification
    Open this publication in new window or tab >>Feature Extraction for Systolic Heart Murmur Classification
    Show others...
    2006 (English)In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 34, no 11, p. 1666-1677Article in journal (Refereed) Published
    Abstract [en]

    Heart murmurs are often the first signs of pathological changes of the heart valves, and they are usually found during auscultation in the primary health care. Distinguishing a pathological murmur from a physiological murmur is however difficult, why an “intelligent stethoscope” with decision support abilities would be of great value. Phonocardiographic signals were acquired from 36 patients with aortic valve stenosis, mitral insufficiency or physiological murmurs, and the data were analyzed with the aim to find a suitable feature subset for automatic classification of heart murmurs. Techniques such as Shannon energy, wavelets, fractal dimensions and recurrence quantification analysis were used to extract 207 features. 157 of these features have not previously been used in heart murmur classification. A multi-domain subset consisting of 14, both old and new, features was derived using Pudil’s sequential floating forward selection (SFFS) method. This subset was compared with several single domain feature sets. Using neural network classification, the selected multi-domain subset gave the best results; 86% correct classifications compared to 68% for the first runner-up. In conclusion, the derived feature set was superior to the comparative sets, and seems rather robust to noisy data.

    Keywords
    Auscultation, Bioacoustics, Feature selection, Heart sounds, Valvular disease
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13044 (URN)10.1007/s10439-006-9187-4 (DOI)
    Available from: 2008-03-20 Created: 2008-03-20 Last updated: 2017-12-13
    5. Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction
    Open this publication in new window or tab >>Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction
    2005 (English)In: IEEE Signal Processing Letters, ISSN 1070-9908, E-ISSN 1558-2361, Vol. 12, no 12, p. 812-815Article in journal (Refereed) Published
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0.34/spl plusmn/0.25, 0.50/spl plusmn/0.33, 0.46/spl plusmn/0.35, and 0.94/spl plusmn/0.64 dB/Hz in the frequency bands 20-40, 40-70, 70-150, and 150-300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

    Place, publisher, year, edition, pages
    Institutionen för medicinsk teknik, 2005
    Keywords
    Bioacoustics, heart sound (HS), lung sound (LS), nonlinear prediction, recurrence time statistics
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-11857 (URN)10.1109/LSP.2005.859528 (DOI)
    Note
    Original publication: Ahlstrom, C., Liljefeldt, O., Hult, P. and Ask, P., Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction, 2005, IEEE Signal Processing Letters, (12), 12, 812-815. http://dx.doi.org/10.1109/LSP.2005.859528. Copyright: IEEE, http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=97Available from: 2008-05-20 Created: 2008-05-20 Last updated: 2017-12-13
  • 1027.
    Ahlström, Christer
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Processing of the Phonocardiographic Signal: methods for the intelligent stethoscope2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Phonocardiographic signals contain bioacoustic information reflecting the operation of the heart. Normally there are two heart sounds, and additional sounds indicate disease. If a third heart sound is present it could be a sign of heart failure whereas a murmur indicates defective valves or an orifice in the septal wall. The primary aim of this thesis is to use signal processing tools to improve the diagnostic value of this information. More specifically, three different methods have been developed:

    • A nonlinear change detection method has been applied to automatically detect heart sounds. The first and the second heart sounds can be found using recurrence times of the first kind while the third heart sound can be found using recurrence times of the second kind. Most third heart sound occurrences were detected (98 %), but the amount of false extra detections was rather high (7 % of the heart cycles).

    • Heart sounds obscure the interpretation of lung sounds. A new method based on nonlinear prediction has been developed to remove this undesired disturbance. High similarity was obtained when comparing actual lung sounds with lung sounds after removal of heart sounds.

    • Analysis methods such as Shannon energy, wavelets and recurrence quantification analysis were used to extract information from the phonocardiographic signal. The most prominent features, determined by a feature selection method, were used to create a new feature set for heart murmur classification. The classification result was 86 % when separating patients with aortic stenosis, mitral insufficiency and physiological murmurs.

    The derived methods give reasonable results, and they all provide a step forward in the quest for an intelligent stethoscope, a universal phonocardiography tool able to enhance auscultation by improving sound quality, emphasizing abnormal events in the heart cycle and distinguishing different heart murmurs.

    List of papers
    1. Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction
    Open this publication in new window or tab >>Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction
    2005 (English)In: IEEE Signal Processing Letters, ISSN 1070-9908, E-ISSN 1558-2361, Vol. 12, no 12, p. 812-815Article in journal (Refereed) Published
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0.34/spl plusmn/0.25, 0.50/spl plusmn/0.33, 0.46/spl plusmn/0.35, and 0.94/spl plusmn/0.64 dB/Hz in the frequency bands 20-40, 40-70, 70-150, and 150-300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

    Place, publisher, year, edition, pages
    Institutionen för medicinsk teknik, 2005
    Keywords
    Bioacoustics, heart sound (HS), lung sound (LS), nonlinear prediction, recurrence time statistics
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-11857 (URN)10.1109/LSP.2005.859528 (DOI)
    Note
    Original publication: Ahlstrom, C., Liljefeldt, O., Hult, P. and Ask, P., Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction, 2005, IEEE Signal Processing Letters, (12), 12, 812-815. http://dx.doi.org/10.1109/LSP.2005.859528. Copyright: IEEE, http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=97Available from: 2008-05-20 Created: 2008-05-20 Last updated: 2017-12-13
    2. Detection of the 3rd Heart Sound using Recurrence Time Statistics
    Open this publication in new window or tab >>Detection of the 3rd Heart Sound using Recurrence Time Statistics
    2006 (English)In: Proc. 31st IEEE Int. Conf. on Acoustics, Speech and Signal Processing, Toulouse, France, 2006, 2006, p. 1040-1043Conference paper, Published paper (Other academic)
    Abstract [en]

    The 3rd heart sound (S3) is normally heard during auscultation of younger individuals, but it is also common in many patients with heart failure. Compared to the 1st and 2nd heart sounds, S3 has low amplitude and low frequency content, making it hard to detect (both manually for the physician and automatically by a detection algorithm). We present an algorithm based on a recurrence time statistic which is sensitive to changes in a reconstructed state space, particularly for detection of transitions with very low energy. Heart sound signals from ten children were used in this study. Most S3 occurrences were detected (98 %), but the amount of false extra detections was rather high (7% of the heart cycles). In conclusion, the method seems capable of detecting S3 with high accuracy and robustness.

    Series
    IEEE International Conference on Acoustics, Speech and Signal Processing. Proceedings, ISSN 1520-6149
    Keywords
    acoustic, signal detection, bioacoustics, signal reconstruction, statistics, heart sound, auscultation, heart failure, reconstructed state space, recurrence time statistics
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-14058 (URN)
    Available from: 2006-10-09 Created: 2006-10-09 Last updated: 2009-04-21
    3. Feature Extraction for Systolic Heart Murmur Classification
    Open this publication in new window or tab >>Feature Extraction for Systolic Heart Murmur Classification
    Show others...
    2006 (English)In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 34, no 11, p. 1666-1677Article in journal (Refereed) Published
    Abstract [en]

    Heart murmurs are often the first signs of pathological changes of the heart valves, and they are usually found during auscultation in the primary health care. Distinguishing a pathological murmur from a physiological murmur is however difficult, why an “intelligent stethoscope” with decision support abilities would be of great value. Phonocardiographic signals were acquired from 36 patients with aortic valve stenosis, mitral insufficiency or physiological murmurs, and the data were analyzed with the aim to find a suitable feature subset for automatic classification of heart murmurs. Techniques such as Shannon energy, wavelets, fractal dimensions and recurrence quantification analysis were used to extract 207 features. 157 of these features have not previously been used in heart murmur classification. A multi-domain subset consisting of 14, both old and new, features was derived using Pudil’s sequential floating forward selection (SFFS) method. This subset was compared with several single domain feature sets. Using neural network classification, the selected multi-domain subset gave the best results; 86% correct classifications compared to 68% for the first runner-up. In conclusion, the derived feature set was superior to the comparative sets, and seems rather robust to noisy data.

    Keywords
    Auscultation, Bioacoustics, Feature selection, Heart sounds, Valvular disease
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-13044 (URN)10.1007/s10439-006-9187-4 (DOI)
    Available from: 2008-03-20 Created: 2008-03-20 Last updated: 2017-12-13
  • 1028.
    Ahlström, Christer
    et al.
    VTI, Swedish Natl Rd and Transport Res Inst, Linkoping, Sweden.
    Anund, Anna
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. VTI, Swedish Natl Rd and Transport Res Inst, Linkoping, Sweden.
    Fors, Carina
    VTI, Swedish Natl Rd and Transport Res Inst, Linkoping, Sweden.
    Åkerstedt, Torbjorn
    Stockholm Univ, Sweden; Karolinska Inst, Sweden.
    Effects of the road environment on the development of driver sleepiness in young male drivers2018In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 112, p. 127-134Article in journal (Refereed)
    Abstract [en]

    Latent driver sleepiness may in some cases be masked by for example social interaction, stress and physical activity. This short-term modulation of sleepiness may also result from environmental factors, such as when driving in stimulating environments. The aim of this study is to compare two road environments and investigate how they affect driver sleepiness. Thirty young male drivers participated in a driving simulator experiment where they drove two scenarios: a rural environment with winding roads and low traffic density, and a suburban road with higher traffic density and a more built-up roadside environment. The driving task was essentially the same in both scenarios, i.e. to stay on the road, without much interaction with other road users. A 2 x 2 design, with the conditions rural versus suburban, and daytime (full sleep) versus night-time (sleep deprived), was used. The results show that there were only minor effects of the road environment on subjective and physiological indicators of sleepiness. In contrast, there was an increase in subjective sleepiness, longer blink durations and increased EEG alpha content, both due to time on task and to night-time driving. The two road environments differed both in terms of the demand on driver action and of visual load, and the results indicate that action demand is the more important of the two factors. The notion that driver fatigue should be countered in a more stimulating visual environment such as in the city is thus more likely due to increased task demand rather than to a richer visual scenery. This should be investigated in further studies.

  • 1029.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Rask, Peter
    University Hospital, Örebro, Sweden .
    Karlsson, Jan-Erik
    County Hospital Ryhov, Jönköping, Sweden.
    Nylander, Eva
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlström, Ulf
    Linköping University, Department of Medicine and Care, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Assessment of Suspected Aortic Stenosis by Auto Mutual Information Analysis of Murmurs2007In: Engineering in Medicine and Biology Society, 2007. EMBS 2007, 2007, p. 1945-1948Conference paper (Refereed)
    Abstract [en]

    Mild sclerotic thickening of the aortic valve affects 25% of the population, and the condition causes aortic valve stenosis (AS) in 2% of adults above 65 years. Echocardiography is today the clinical standard for assessing AS. However, a cost effective and uncomplicated technique that can be used for decision support in the primary health care would be of great value. In this study, recorded phonocardiographic signals were analyzed using the first local minimum of the auto mutual information (AMI) function. The AMI method measures the complexity in the sound signal, which is related to the amount of turbulence in the blood flow and thus to the severity of the stenosis. Two previously developed phonocardiographic methods for assessing AS severity were used for comparison, the murmur energy ratio and the sound spectral averaging technique. Twenty-nine patients with suspected AS were examined with Doppler echocardiography. The aortic jet velocity was used as a reference of AS severity, and it was found to correlate with the AMI method, the murmur energy ratio and the sound spectral averaging technique with the correlation coefficient R = 0.82, R = 0.73 and R = 0.76, respectively.

  • 1030.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Arts and Sciences.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Detection of the 3(rd) heart sound using recurrence time statistics2006In: 2006 IEEE International Conference on Acoustics, Speech and Signal Processing, Vols 1-13, 2006, Vol. 1-13, p. 2288-2291Conference paper (Refereed)
    Abstract [en]

    The 3(rd) heart sound (S3) is normally heard during auscultation of younger individuals, but it is also common in many patients with heart failure. Compared to the 1(st) and 2(nd) heart sounds, S3 has low amplitude and low frequency content, making it hard to detect (both manually for the physician and automatically by a detection algorithm). We present an algorithm based on a recurrence time statistic which is sensitive to changes in a reconstructed state space, particularly for detection of transitions with very low energy. Heart sound signals from ten children were used in this study. Most S3 occurrences were detected (98%), but the amount of false extra detections was rather high (7% of the heart cycles). In conclusion, the method seems capable of detecting S3 with high accuracy and robustness.

  • 1031.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Detection of the 3rd Heart Sound using Recurrence Time Statistics2006In: Proc. 31st IEEE Int. Conf. on Acoustics, Speech and Signal Processing, Toulouse, France, 2006, 2006, p. 1040-1043Conference paper (Other academic)
    Abstract [en]

    The 3rd heart sound (S3) is normally heard during auscultation of younger individuals, but it is also common in many patients with heart failure. Compared to the 1st and 2nd heart sounds, S3 has low amplitude and low frequency content, making it hard to detect (both manually for the physician and automatically by a detection algorithm). We present an algorithm based on a recurrence time statistic which is sensitive to changes in a reconstructed state space, particularly for detection of transitions with very low energy. Heart sound signals from ten children were used in this study. Most S3 occurrences were detected (98 %), but the amount of false extra detections was rather high (7% of the heart cycles). In conclusion, the method seems capable of detecting S3 with high accuracy and robustness.

  • 1032.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Thresholding distance plots using true recurrence points2006In: Acoustics, Speech and Signal Processing, 2006. ICASSP 2006, IEEE , 2006, p. 688-691Conference paper (Refereed)
    Abstract [en]

    Recurrence plots (RP) visualize multi-dimensional state spaces and represent the recurrence of states of a system. Recurrence points can be divided into true recurrence points and false recurrence points (also called sojourn points). We introduce the true recurrence point recurrence plot, TRP, a variant of the traditional RP excluding the sojourn points. This is a cleaned up RP free from recurrence points originating from tangential motion, and hence a more robust representation of unstable periodic orbits. The method is demonstrated with three simple systems, a periodic sine wave, a quasi-periodic torus and the x-component of the chaotic Lorenz system

  • 1033.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Wheeze analysis and detection with non-linear phase-space embedding2005In: Nordic Baltic Conference Biomedical Engineering and Medical Physics,2005, Umeå: IFMBE , 2005, p. 305-Conference paper (Refereed)
  • 1034.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Rask, P
    Karlsson, J-E
    Nylander, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlström, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Using the intelligent stethoscope for extraction of features for systolic heart murmur classification2006In: World Congress on Medical Physics and Biomedical Engineering WC2006,2006, 2006Conference paper (Other academic)
  • 1035.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Rask, Peter
    Örebro university.
    Karlsson, Jan-Erik
    Nylander, Eva
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlström, Ulf
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Feature Extraction for Systolic Heart Murmur Classification2006In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 34, no 11, p. 1666-1677Article in journal (Refereed)
    Abstract [en]

    Heart murmurs are often the first signs of pathological changes of the heart valves, and they are usually found during auscultation in the primary health care. Distinguishing a pathological murmur from a physiological murmur is however difficult, why an “intelligent stethoscope” with decision support abilities would be of great value. Phonocardiographic signals were acquired from 36 patients with aortic valve stenosis, mitral insufficiency or physiological murmurs, and the data were analyzed with the aim to find a suitable feature subset for automatic classification of heart murmurs. Techniques such as Shannon energy, wavelets, fractal dimensions and recurrence quantification analysis were used to extract 207 features. 157 of these features have not previously been used in heart murmur classification. A multi-domain subset consisting of 14, both old and new, features was derived using Pudil’s sequential floating forward selection (SFFS) method. This subset was compared with several single domain feature sets. Using neural network classification, the selected multi-domain subset gave the best results; 86% correct classifications compared to 68% for the first runner-up. In conclusion, the derived feature set was superior to the comparative sets, and seems rather robust to noisy data.

  • 1036.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Schmekel, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Automatisk detektering av ronki med icke-linjära metoder2004In: Svenska Läkaresällskapets riksstämma,2004, 2004, p. 66-66Conference paper (Other academic)
  • 1037.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Schmekel, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Wheeze detection with nonlinear statespace embedding2004In: International Lung Sound Association,2004, 2004, p. 38-39Conference paper (Other academic)
  • 1038.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Höglund, Katja
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Häggström, Jens
    Kvart, Clarence
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Assessing Aortic Stenosis using Sample Entropy of the Phonocardiographic Signal in Dogs2008In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 55, no 8, p. 2107-2109Article in journal (Refereed)
    Abstract [en]

    In aortic valve stenosis (AS), heart murmurs arise as an effect of turbulent blood flow distal to the obstructed valves. With increasing AS severity, the flow becomes more unstable, and the ensuing murmur becomes more complex. We hypothesize that these hemodynamic flow changes can be quantified based on the complexity of the phonocardiographic (PCG) signal. In this study, sample entropy (SampEn) was investigated as a measure of complexity using a dog model. Twenty-seven boxer dogs with various degrees of AS were examined with Doppler echocardiography, and the peak aortic flow velocity (Vmax) was used as a reference of AS severity. SampEn correlated to Vmax with R = 0.70 using logarithmic regression. In a separate analysis, significant differences were found between physiologic murmurs and murmurs caused by AS (p < 0.05), and the area under a receiver operating characteristic curve was calculated to 0.96. Comparison with previously presented PCG measures for AS assessment showed improved performance when using SampEn, especially for differentiation between physiological murmurs and murmurs caused by mild AS. Studies in patients will be needed to properly assess the technique in humans.

  • 1039.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Höglund, Katja
    Dept. of Anatomy and Physiology, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Häggström, Jens
    Dept. of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Kvart, Clarence
    Dept. of Anatomy and Physiology, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Distinguishing Innocent Murmurs from Murmurs caused by Aortic Stenosis by Recurrence Quantification Analysis2006In: ROCEEDINGS OF WORLD ACADEMY OF SCIENCE, ENGINEERING AND TECHNOLOGY, VOL 18, Canakkale, Turkey: World Academy of Science, Engineering and Technology (W A S E T) , 2006, p. 40-45Conference paper (Refereed)
    Abstract [en]

    It is sometimes difficult to differentiate between innocent murmurs and pathological murmurs during auscultation. In these difficult cases, an intelligent stethoscope with decision support abilities would be of great value. In this study, using a dog model, phonocardiographic recordings were obtained from 27 boxer dogs with various degrees of aortic stenosis (AS) severity. As a reference for severity assessment, continuous wave Doppler was used. The data were analyzed with recurrence quantification analysis (RQA) with the aim to find features able to distinguish innocent murmurs from murmurs caused by AS. Four out of eight investigated RQA features showed significant differences between innocent murmurs and pathological murmurs. Using a plain linear discriminant analysis classifier, the best pair of features (recurrence rate and entropy) resulted in a sensitivity of 90% and a specificity of 88%. In conclusion, RQA provide valid features which can be used for differentiation between innocent murmurs and murmurs caused by AS.

  • 1040.
    Ahlström, Christer
    et al.
    Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Jansson, Sabina
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Anund, Anna
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Rehabilitation Medicine. Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Local changes in the wake electroencephalogram precedes lane departures2017In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 26, no 6, p. 816-819Article in journal (Refereed)
    Abstract [en]

    The objective of this exploratory study is to investigate if lane departures are associated with local sleep, measured via source-localized electroencephalography (EEG) theta power in the 5-9 Hz frequency range. Thirty participants drove in an advanced driving simulator, resulting in 135 lane departures at high levels of self-reported sleepiness. These lane departures were compared to matching non-departures at the same sleepiness level within the same individual. There was no correspondence between lane departures and global theta activity. However, at the local level an increased risk for lane departures was associated with increased theta content in brain regions related to motor function.

  • 1041.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Hult, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Chaotic dynamics of respiratory sounds2006In: Chaos, Solitons & Fractals, ISSN 0960-0779, E-ISSN 1873-2887, Vol. 29, no 5, p. 1054-1062Article in journal (Refereed)
    Abstract [en]

    There is a growing interest in nonlinear analysis of respiratory sounds (RS), but little has been done to justify the use of nonlinear tools on such data. The aim of this paper is to investigate the stationarity, linearity and chaotic dynamics of recorded RS. Two independent data sets from 8 + 8 healthy subjects were recorded and investigated. The first set consisted of lung sounds (LS) recorded with an electronic stethoscope and the other of tracheal sounds (TS) recorded with a contact accelerometer. Recurrence plot analysis revealed that both LS and TS are quasistationary, with the parts corresponding to inspiratory and expiratory flow plateaus being stationary. Surrogate data tests could not provide statistically sufficient evidence regarding the nonlinearity of the data. The null hypothesis could not be rejected in 4 out of 32 LS cases and in 15 out of 32 TS cases. However, the Lyapunov spectra, the correlation dimension (D2) and the Kaplan-Yorke dimension (DKY) all indicate chaotic behavior. The Lyapunov analysis showed that the sum of the exponents was negative in all cases and that the largest exponent was found to be positive. The results are partly ambiguous, but provide some evidence of chaotic dynamics of RS, both concerning LS and TS. The results motivate continuous use of nonlinear tools for analysing RS data. © 2005 Elsevier Ltd. All rights reserved.

  • 1042.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    A respiration monitor based on electrocardiographic and photoplethysmographic sensor fusion2004In: IEEE Engineering in Medical and Biological Society,2004, Piscataway, N.J. USA: IEEEEMBS , 2004, p. 2311-Conference paper (Refereed)
  • 1043.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Monitorering av andning and blodtrycksförändringar baserat på EKG och hjärtljud2007In: Medicinteknik dagarna,2007, 2007Conference paper (Other academic)
  • 1044.
    Ahlström, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Johansson, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Uhlin, Fredrik
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Noninvasive investigation of blood pressure changes using the pulse wave transit time: A novel approach in the monitoring of hemodialysis patients2005In: Journal of Artificial Organs, ISSN 1434-7229, E-ISSN 1619-0904, Vol. 8, no 3, p. 192-197Article in journal (Refereed)
    Abstract [en]

    Severe blood pressure changes are well known in hemodialysis. Detection and prediction of these are important for the well-being of the patient and for optimizing treatment. New noninvasive methods for this purpose are required. The pulse wave transit time technique is an indirect estimation of blood pressure, and our intention is to investigate whether this technique is applicable for hemodialysis treatment. A measurement setup utilizing lower body negative pressure and isometric contraction was used to simulate dialysis-related blood pressure changes in normal test subjects. Systolic blood pressure levels were compared to different pulse wave transit times, including and excluding the cardiac preejection period. Based on the results of these investigations, a pulse wave transit time technique adapted for dialysis treatment was developed and tried out on patients. To determine systolic blood pressure in the normal group, the total pulse wave transit time was found most suitable (including the cardiac preejection period). Correlation coefficients were r = 0.80 ± 0.06 (mean ± SD) overall and r = 0.81 ± 0.16 and r = 0.09 ± 0.62 for the hypotension and hypertension phases, respectively. When applying the adapted technique in dialysis patients, large blood pressure variations could easily be detected when present. Pulse wave transit time is correlated to systolic blood pressure within the acceptable range for a trend-indicating system. The method's applicability for dialysis treatment requires further studies. The results indicate that large sudden pressure drops, like those seen in sudden hypovolemia, can be detected. © The Japanese Society for Artificial Organs 2005.

  • 1045.
    Ahlström, Christer
    et al.
    Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Kircher, Katja
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences. Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    A Generalized Method to Extract Visual Time-Sharing Sequences From Naturalistic Driving Data2017In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 18, no 11, p. 2929-2938Article in journal (Refereed)
    Abstract [en]

    Indicators based on visual time-sharing have been used to investigate drivers visual behaviour during additional task execution. However, visual time-sharing analyses have been restricted to additional tasks with well-defined temporal start and end points and a dedicated visual target area. We introduce a method to automatically extract visual time-sharing sequences directly from eye tracking data. This facilitates investigations of systems, providing continuous information without well-defined start and end points. Furthermore, it becomes possible to investigate time-sharing behavior with other types of glance targets such as the mirrors. Time-sharing sequences are here extracted based on between-glance durations. If glances to a particular target are separated by less than a time-based threshold value, we assume that they belong to the same information intake event. Our results indicate that a 4-s threshold is appropriate. Examples derived from 12 drivers (about 100 hours of eye tracking data), collected in an on-road investigation of an in-vehicle information system, are provided to illustrate sequence-based analyses. This includes the possibility to investigate human-machine interface designs based on the number of glances in the extracted sequences, and to increase the legibility of transition matrices by deriving them from time-sharing sequences instead of single glances. More object-oriented glance behavior analyses, based on additional sensor and information fusion, are identified as the next future step. This would enable automated extraction of time-sharing sequences not only for targets fixed in the vehicles coordinate system, but also for environmental and traffic targets that move independently of the drivers vehicle.

  • 1046.
    Ahlström, Christer
    et al.
    Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Kircher, Katja
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences. Swedish National Rd and Transport Research Institute VTI, S-58195 Linkoping, Sweden.
    Changes in glance behaviour when using a visual eco-driving system - A field study2017In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 58, p. 414-423Article in journal (Refereed)
    Abstract [en]

    While in-vehicle eco-driving support systems have the potential to reduce greenhouse gas emissions and save fuel, they may also distract drivers, especially if the system makes use of a visual interface. The objective of this study is to investigate the visual behaviour of drivers interacting with such a system, implemented on a five-inch screen mounted above the middle console. Ten drivers participated in a real world, on-road driving study where they drove a route nine times (2 pre-baseline drives, 5 treatment drives, 2 post-baseline drives). The route was 96 km long and consisted of rural roads, urban roads and a dual-lane motorway. The results show that drivers look at the system for 5-8% of the time, depending on road type, with a glance duration of about 0.6 s, and with 0.05% long glances (amp;gt;2s) per kilometre. These figures are comparable to what was found for glances to the speedometer in this study. Glance behaviour away from the windscreen is slightly increased in treatment as compared to pre- and post-baseline, mirror glances decreased in treatment and post-baseline compared to pre-baseline, and speedometer glances increased compared to pre-baseline. The eco-driving support system provided continuous information interspersed with additional advice pop-ups (announced by a beep) and feedback pop-ups (no auditory cue). About 20% of sound initiated advice pop-ups were disregarded, and the remaining cases were usually looked at within the first two seconds. About 40% of the feedback pop-ups were disregarded. The amount of glances to the system immediately before the onset of a pop-up was clearly higher for feedback than for advice. All in all, the eco-driving support system under investigation is not likely to have a strong negative impact on glance behaviour. However, there is room for improvements. We recommend that eco-driving information is integrated with the speedometer, that optional activation of sound alerts for intermittent information is made available, and that the pop-up duration should be extended to facilitate self-regulation of information intake. (C) 2016 Elsevier Ltd. All rights reserved.

  • 1047.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Kircher, Albert
    Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    A Gaze-Based Driver Distraction Warning System and Its Effect on Visual Behavior2013In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 14, no 2, p. 965-973Article in journal (Refereed)
    Abstract [en]

    Driver distraction is a contributing factor to many crashes; therefore, a real-time distraction warning system should have the potential to mitigate or circumvent many of these crashes. The objective of this paper is to investigate the usefulness of a real-time distraction detection algorithm called AttenD. The evaluation is based on data from an extended field study comprising seven drivers who drove on an average of 4351 +/- 2181 km in a naturalistic setting. Visual behavior was investigated both on a global scale and on a local scale in the surroundings of each warning. An increase in the percentage of glances at the rear-view mirror and a decrease in the amount of glances at the center console were found. The results also show that visual time sharing decreased in duration from 9.94 to 9.20 s due to the warnings, that the time from fully attentive to warning decreased from 3.20 to 3.03 s, and that the time from warning to full attentiveness decreased from 6.02 to 5.46 s. The limited number of participants does not allow any generalizable conclusions, but a trend toward improved visual behavior could be observed. This is a promising start for further improvements of the algorithm and the warning strategy.

  • 1048.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering.
    Liljefeldt, Olle
    Hult, Peter
    Linköping University, Department of Biomedical Engineering.
    Ask, Per
    Linköping University, Department of Biomedical Engineering.
    Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction.2005In: Medicinteknikdagarna, 2005, Vol. 12, p. 812-815Conference paper (Other academic)
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0 34 0 25, 0 50 0 33, 0 46 0 35, and 0 94 0 64 dB/Hz in the frequency bands 20–40, 40–70, 70–150, and 150–300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

  • 1049.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Liljefeldt, Olle
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Heart sound cancellation from lung sound recordings using recurrence time statistics and nonlinear prediction2005In: IEEE Signal Processing Letters, ISSN 1070-9908, E-ISSN 1558-2361, Vol. 12, no 12, p. 812-815Article in journal (Refereed)
    Abstract [en]

    Heart sounds (HS) obscure the interpretation of lung sounds (LS). This letter presents a new method to detect and remove this undesired disturbance. The HS detection algorithm is based on a recurrence time statistic that is sensitive to changes in a reconstructed state space. Signal segments that are found to contain HS are removed, and the arising missing parts are replaced with predicted LS using a nonlinear prediction scheme. The prediction operates in the reconstructed state space and uses an iterated integrated nearest trajectory algorithm. The HS detection algorithm detects HS with an error rate of 4% false positives and 8% false negatives. The spectral difference between the reconstructed LS signal and an LS signal with removed HS was 0.34/spl plusmn/0.25, 0.50/spl plusmn/0.33, 0.46/spl plusmn/0.35, and 0.94/spl plusmn/0.64 dB/Hz in the frequency bands 20-40, 40-70, 70-150, and 150-300 Hz, respectively. The cross-correlation index was found to be 99.7%, indicating excellent similarity between actual LS and predicted LS. Listening tests performed by a skilled physician showed high-quality auditory results.

  • 1050.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Johansson, Anders
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    A method for accurate localization of the first heart sound and possible applications2008In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 29, no 3, p. 417-428Article in journal (Refereed)
    Abstract [en]

    We have previously developed a method for localization of the first heart sound (S1) using wavelet denoising and ECG-gated peak-picking. In this study, an additional enhancement step based on cross-correlation and ECG-gated ensemble averaging (EA) is presented. The main objective of the improved method was to localize S1 with very high temporal accuracy in (pseudo-) real time. The performance of S1 detection and localization, with and without EA enhancement, was evaluated on simulated as well as experimental data. The simulation study showed that EA enhancement reduced the localization error considerably and that S1 could be accurately localized at much lower signal-to-noise ratios. The experimental data were taken from ten healthy subjects at rest and during invoked hyper- and hypotension. For this material, the number of correct S1 detections increased from 91% to 98% when using EA enhancement. Improved performance was also demonstrated when EA enhancement was used for continuous tracking of blood pressure changes and for respiration monitoring via the electromechanical activation time. These are two typical applications where accurate localization of S1 is essential for the results.

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