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  • 102051.
    Åström, Freddie
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Felsberg, Michael
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Baravdish, George
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Lundström, Claes
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Targeted Iterative Filtering2013Conference paper (Refereed)
    Abstract [en]

    The assessment of image denoising results depends on the respective application area, i.e. image compression, still-image acquisition, and medical images require entirely different behavior of the applied denoising method. In this paper we propose a novel, nonlinear diffusion scheme that is derived from a linear diffusion process in a value space determined by the application. We show that application-driven linear diffusion in the transformed space compares favorably with existing nonlinear diffusion techniques. 

  • 102052.
    Åström, Freddie
    et al.
    Heidelberg Collaboratory for Image Processing Heidelberg University Heidelberg, Germany.
    Felsberg, Michael
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Scharr, Hanno
    BG-2: Plant Sciences Forschungszentrum Jülich 52425, Jülich, Germany.
    Adaptive sharpening of multimodal distributions2015In: Colour and Visual Computing Symposium (CVCS), 2015 / [ed] Marius Pedersen and Jean-Baptiste Thomas, IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    In this work we derive a novel framework rendering measured distributions into approximated distributions of their mean. This is achieved by exploiting constraints imposed by the Gauss-Markov theorem from estimation theory, being valid for mono-modal Gaussian distributions. It formulates the relation between the variance of measured samples and the so-called standard error, being the standard deviation of their mean. However, multi-modal distributions are present in numerous image processing scenarios, e.g. local gray value or color distributions at object edges, or orientation or displacement distributions at occlusion boundaries in motion estimation or stereo. Our method not only aims at estimating the modes of these distributions together with their standard error, but at describing the whole multi-modal distribution. We utilize the method of channel representation, a kind of soft histogram also known as population codes, to represent distributions in a non-parametric, generic fashion. Here we apply the proposed scheme to general mono- and multimodal Gaussian distributions to illustrate its effectiveness and compliance with the Gauss-Markov theorem.

  • 102053.
    Åström, Freddie
    et al.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Koker, Rasit
    Engineering Faculty Esentepe Kampus, Computer Engineering Department, Sakarya University, Turkey.
    A parallel neural network approach to prediction of Parkinson´s Disease2011In: Expert systems with applications, ISSN 0957-4174, E-ISSN 1873-6793, Vol. 38, no 10, p. 12470-12474Article in journal (Refereed)
    Abstract [en]

    Recently the neural network based diagnosis of medical diseases has taken a great deal of attention. In this paper a parallel feed-forward neural network structure is used in the prediction of Parkinson’s Disease. The main idea of this paper is using more than a unique neural network to reduce the possibility of decision with error. The output of each neural network is evaluated by using a rule-based system for the final decision. Another important point in this paper is that during the training process, unlearned data of each neural network is collected and used in the training set of the next neural network. The designed parallel network system significantly increased the robustness of the prediction. A set of nine parallel neural networks yielded an improvement of 8.4% on the prediction of Parkinson’s Disease compared to a single unique network. Furthermore, it is demonstrated that the designed system, to some extent, deals with the problems of imbalanced data sets.

  • 102054.
    Åström, Freddie
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Zografos, Vasileios
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Felsberg, Michael
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Density Driven Diffusion2013In: 18th Scandinavian Conferences on Image Analysis, 2013, 2013, p. 718-730Conference paper (Refereed)
    Abstract [en]

    In this work we derive a novel density driven diffusion scheme for image enhancement. Our approach, called D3, is a semi-local method that uses an initial structure-preserving oversegmentation step of the input image.  Because of this, each segment will approximately conform to a homogeneous region in the image, allowing us to easily estimate parameters of the underlying stochastic process thus achieving adaptive non-linear filtering. Our method is capable of producing competitive results when compared to state-of-the-art methods such as non-local means, BM3D and tensor driven diffusion on both color and grayscale images.

  • 102055.
    Åström, Henning
    Linköping University, Department of Thematic Studies.
    Ett hållbart kretslopp?: Förutsättningar för återföring av näringsämnen i humanavlopp till odlad mark; Norrköpings kommun som exempel2005Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    The study examins if returning of nutrients, mainly the macronutriens nitrogen and phosphorus, from sewage in the municipality of Norrköping can be done in way that corresponds to natural scientiffic principals of circulation of material.

    The issue of returning of nutrients and the presentation of the problem are of great importance when the fluxes of today are leading to a waste of resources and the environmental problem eutrophication. The reason for nutrients are not recycled must be some sort of incapability of the involved actors to deal with the problem.

    The study analyses perspectives of different actors. The actors are described in a national as well as a more focused municipal perspective. This is because of the part that the municipality is playing implies that they are ultimately responsible for the shaping of the sewersystem. The ones that are acting in relation to the municipality have because of this been examined thru interviews with representatives for the actors.

    The study is thus a casestudy where the municipality of Norrköping is studied and the actors chosen is the sewage treatment plant of Slottshagen, the county administrative board of Östergötland, a branch of the Swedish farmers cooperation “Lantmännen” and the health and environment office of the municipality. The empirical material shows that the actors are not adopting a recycle-perspective and that they tend to adopt an economical perspective when they deal with the problem. This can cause problems in a ecological context and obstruct a positive development in dealing with environmental problems. The study relates the results and the responsibility of the actors to the common view of the way of dealing with environmental issues that is recommended thru the Swedish environmental law.

  • 102056.
    Åström, I. Maria
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Differences between students in Swedish compulsory schools with integrated andsubject-specific Science education in PISA 2006Manuscript (Other academic)
    Abstract [en]

    This study is a comparison between three groups of teaching organisations in Sweden that work either with integrated Science, subject-specific Science or a mixed form of the two. Comparison is made between the students’ total Science scores in the PISA 2006 study and the three scores in student competency regarding Knowledge in Science and Knowledge about Science. This comparison is made both at the individual and school level. There are differences between students with integrated Science education and students with subjectspecific Science. These differences are found both in the total scores and in some of the subscores. An even more striking difference is found between boys and girls in the different groups. There are big differences in test scores for girls with integrated Science as compared to girls with subject-specific Science; this difference is almost nonexistent for boys. Some caution must be shown in drawing conclusions from this finding, however, since girls’ and boys’ groups differ in mean ESCS, and there are differences in the percentage of students who speak another language at home than Swedish. Some plausible explanations for the differences are discussed based on inferences from other studies.

  • 102057.
    Åström, I. Maria
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    En Delphi-studie av initierade brukaresuppfattningar om karaktärer av integreradnaturvetenskap i senare delen av svensk grundskola2009In: Didaktisk Tidskrift, ISSN 1101-7686, Vol. 19, no 3, p. 114-132Article in journal (Other academic)
    Abstract [en]

    Den här studien undersöker hur experter, väl insatta i den svenska debatten om integrerad NO uppfattar vad integrerad NO är, hur den tillämpas och vilka skäl som finns för att undervisa integrerat i NO istället för att undervisa ämnesuppdelat. Diskussionen om integrerad eller ämnesuppdelad NO hade en kulmen på 1980-talet i Sverige som gav två varianter att undervisa NO på i grundskolan, antingen som ett ämne eller som tre ämnen, biologi, kemi och fysik. Dessa varianter finns åtminstone som två likvärdiga sätt att gradera betyg på. Nu är det aktuellt att ta bort denna möjlighet att sätta NO-betyg eller biologi-, fysik- och kemibetyg, vilket gör det intressant att undersöka hur idén om vad integrerad och ämnesuppdelad NO-undervisning har för likheter och skillnader. Undersökningen är genomförd som en Delphistudie, där de tillfrågade deltagarna anonymt har värderat 30 påståenden om integrerad och ämnesuppdelad undervisning i ett första steg. Svaren sammanställdes med medelvärden och medianer och presenterades för deltagarna i en andra enkätomgång. Informanterna erbjöds möjlighet att ändra sina svar efter att ha tagit del i de övriga deltagarnas värderingar av påståendena i form av centralmått på frågorna. Resultatet av den första undersökningsomgången redovisas i tabell där informanternas sammanlagda bedömning eller skattning av påståendena redovisas. Informanternas svar diskuteras och jämförs med den teori som ursprungligen använts för att konstruera frågorna. Metodiska frågor i samband med undersökningen diskuteras också.

  • 102058.
    Åström, I. Maria
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Integrated and Subject-specific: An empirical exploration of Science education in Swedish compulsory school2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is an explorative experimental study in two parts of different ways of organising Science education in the Swedish context. The first study deals with the question if students attain higher scores on test results if they have been working with integrated Science compared to subject-specific Science i.e. Biology, Chemistry and Physics. The second study concerns the similarities and differences between integrated Science education and Science education in Biology, Chemistry and Physics, especially in the teaching organisation.

    The introduction describes the nature of integrated curriculum, what integrated learning is, issues about integrated Science education, in what way integration is carried out, between subjects or within subjects, what the opposite to integrated Science is (here named as subjectspecific science education) in the Swedish context and what the Swedish curriculum has to say about integrated Science. Previous studies in integrated curriculum looking at students’ results are referred to, and it is argued for the use of the OECD’s PISA assessment instrument in this study.

    The thesis consists of two studies, one quantitative and one qualitative, within the above framework. The quantitative study is an attempt to find differences in scores on students’ written results on a large-scale assessment in scientific literacy between students studying in different organisations of Science education. The qualitative study is an attempt to describe differences at classroom level between integrated Science and subject-specific Science. This gives a quite rich description of four schools (cases) in a small town and how they organise their teaching integrated or subject-specific.

    No differences in students’ results between different Science organisations were found in the quantitative study in this thesis. Possible explanations for the lack of differences in students’ results are discussed in the article. An additional investigation that attempts to test the variable used in the quantitative study is carried out in the thesis, with an attempt to sharpen the teacher organisation variable. This is done to find out if it is possible that there can be found differences with the sharpened variable.

    The qualitative study gives a glimpse of some differences in the implemented curriculum between schools working with integrated Science education and a school that works subjectspecifically. The teachers do the overall lesson plans in different ways according to which organisation according to integrated or subject-specific Science they work with. When asked in a survey what kind of Science organisation they have, students from the four schools studied answered differently between schools and also, sometimes, within the same school. A further analysis of this second study is carried out by defining a conceptual framework used as structure and a possible explanation for differences between students’ views and teachers’ views on the organisation of Science education. This latter analysis tries to give an enriched description in mainly the two levels of the implemented and attained curricula, and tries to discuss the difference in students’ attained curriculum.

    A final discussion concludes the thesis and concerns an elaboration of the results of the thesis, problems with the main variable involved in the two studies and the possibility that the teacher actions effects also the magnitude of students’ achievement on tests.

    List of papers
    1. Using hierarchical linear models to test differences in Swedish results from OECD’sPISA 2003: Integrated and subject-specific science education
    Open this publication in new window or tab >>Using hierarchical linear models to test differences in Swedish results from OECD’sPISA 2003: Integrated and subject-specific science education
    2007 (English)In: NorDiNa: Nordic Studies in Science Education, ISSN 1504-4556, E-ISSN 1894-1257, Vol. 3, no 2, p. 121-131Article in journal (Refereed) Published
    Abstract [en]

    The possible effects of different organisations of the science curriculum in schools participating in PISA 2003 are tested with a hierarchical linear model (HLM) of two levels. The analysis is based on science results. Swedish schools are free to choose how they organise the science curriculum. They may choose to work subject-specifically (with Biology, Chemistry and Physics), integrated (with Science) or to mix these two. In this study, all three ways of organising science classes in compulsory school are present to some degree. None of the different ways of organising science education displayed statistically significant better student results in scientific literacy as measured in PISA 2003. The HLM model used variables of gender, country of birth, home language, preschool attendance, an economic, social and cultural index as well as the teaching organisation.

    National Category
    Pedagogy
    Identifiers
    urn:nbn:se:liu:diva-15473 (URN)
    Available from: 2008-11-11 Created: 2008-11-11 Last updated: 2017-12-14Bibliographically approved
    2. Integrated and subject-specific Science education: Teachers’ and students’ views
    Open this publication in new window or tab >>Integrated and subject-specific Science education: Teachers’ and students’ views
    (English)Manuscript (Other academic)
    Abstract [en]

    This study concerns the views of teachers’ and students’ regarding Science education. The teachers and students are all from four schools in the same small town in Sweden. The teachers’ views of Science lessons focused on how to plan lessons and organise content. The students’ views focused on three questions concerning the integration of science. The study is based on several data collections: interviews with and observations of teachers, a school survey and student questionnaires. The teacher interviews were analysed with regard to integrated and subject-specific Science education and the students’ questionnaires were analysed with statistical methods. The four schools in this study may be categorised as two integrated schools, one subject-specific and one mixed school. The students’ views of subjectspecific and integrated Science did not completely coincide with the teachers’ views. Teachers and students agreed on that they did integrated education in only one out of the four schools.

    Keywords
    Science education, teachers’ and students’ views, integrated and subject specific Science
    National Category
    Pedagogy
    Identifiers
    urn:nbn:se:liu:diva-15475 (URN)
    Available from: 2008-11-11 Created: 2008-11-11 Last updated: 2010-01-14Bibliographically approved
  • 102059.
    Åström, I. Maria
    et al.
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Karl-Göran , Karlsson
    Department of Engineering, Physics and Mathematics, Mid Sweden University.
    Integrated and subject-specific Science education: Teachers’ and students’ viewsManuscript (Other academic)
    Abstract [en]

    This study concerns the views of teachers’ and students’ regarding Science education. The teachers and students are all from four schools in the same small town in Sweden. The teachers’ views of Science lessons focused on how to plan lessons and organise content. The students’ views focused on three questions concerning the integration of science. The study is based on several data collections: interviews with and observations of teachers, a school survey and student questionnaires. The teacher interviews were analysed with regard to integrated and subject-specific Science education and the students’ questionnaires were analysed with statistical methods. The four schools in this study may be categorised as two integrated schools, one subject-specific and one mixed school. The students’ views of subjectspecific and integrated Science did not completely coincide with the teachers’ views. Teachers and students agreed on that they did integrated education in only one out of the four schools.

  • 102060.
    Åström, Jan
    Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Linköping University, Faculty of Health Sciences.
    Introductory greeting behaviour in relation to sex, age, physical characteristics, attitudes, personality, and psychopathology: Approaches by interviews, observations, and experiments1993Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The overall aim of this thesis was to elucidate, through interviews, observations and experiments, elements of the introductory greeting, such as sex, age, physical characteristics, personality, and psychopathology, in a psychotherapeutic situation. As an introductory greeting it was considered here the ftrst occasion the therapist and the patient greet each other in the waiting room.

    Papers I - III in the thesis deal with the construction of an interview questionnaire, its psychometric properties and use among psychotherapists (n= 79) and psychotherapeutic out-patients (n= 50). Psychotherapists were interviewed about their attitudes towards and observations of nonverbal communication in an introductory greeting situation. The results from the interview were related to therapists' background variables such as sex, age, clinical experience, and theoretical orientation. Psychotherapeutic out-patients were interviewed in a similar way.

    Paper IV deals with rated handshaking in psychiatric patients (n= 29) related to personality traits according to an abbreviated scale of Minnesota Multiphasic Personality Inventory (MMPI), the Faschingbauer Abbreviated MMPI (FAM), clinical diagnoses, and psychosocial functioning. Four handshaking variables were rated independently by two raters in a ftve steps scale: the perceived Consistency, Temperature, Dryness and Strength of the hand. The interrater reliability was satisfactory.

    Papers V - VI deal with the greeting behaviour of healthy subjects (n= 50) in an experimental setting. The introductory greeting behaviour was fthned and nonverbal immediacy behaviour (NVIB) analysed in the approaching and close salutation phases together with the handshaking variables, and related to some back-ground variables such as sex, age, body height, vigour of the hand, and personality traits.

    The interview questionnaire possessed satisfactory psychometric qualities (Paper I). Female psychotherapists paid signiftcantly greater importance to 'face communication in the greeting situation compared to male therapists. Great importance attached to nonverbal communication in psychotherapy was related to being well-kept and to perform correctly in front of the patient, to establish direct communication in the greeting situation, and to frequent work in psychotherapy and an eclectic psychotherapeutic orientation (Paper II). The importance of the face as a mean of contact in nonverbal communication was particularly stressed by female, mainly older patients who believed that 'face communication' covers more than 50 percent of the total communication in human interactions (Paper III).

    The findings in psychiatric patients (Paper IV) indicate that the handshaking procedure may transmit information about personality make-up. Low temperature and humidity of the palmar skin were related to social introversion, depression, and tendency to symptom enhancement mainly in women.

    The reliability and stability over time of nonverbal immediacy behaviour (physic and psychological closeness) and handshake characteristics in the experimental study were on the whole satisfactory (Papers V - VI). Women displayed greater intimacy behaviour (less physical distance and presence of smile) in their greeting behaviour than males. Statistically signiftcant correlations between variables of handshaking and personality traits were noted. Strength of the hand in particular was related to extraversion loaded traits as dominance, aggression and exhibition.

  • 102061.
    Åström, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry.
    Paulin, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Thorell, Lars-Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Inner images and delineations of parental figures reported by psychotherapeutic outpatients2006In: Perceptual and Motor Skills, ISSN 0031-5125, E-ISSN 1558-688X, Vol. 103, no 3, p. 931-945Article in journal (Refereed)
    Abstract [en]

    Psychotherapeutic outpatients (10 men, 20 women) were tested with the Inner Images of Parental Figures. Each subject imagined first his mother and then his father. Questions were asked about size, look, and spatial and emotional distance of the imagined parent. The patient was then asked to describe the personality of each parent by underlining at least 20 of 85 adjectives in a list called Family Climate Scale. This originally consisted of four factors, Closeness, Spontaneity, Distance, and Chaos, but the two administered were Factor I (positive traits) and Factor II (negative traits). Emotional distance correlated positively with Factor I and negatively with Factor II. For the maternal figure there was a correlation with distance in metres and Factor I scores. The Inner Images of Parental Figures may be a valuable complement in psychotherapy, mapping out emotional relations between patients and their parents. © Perceptual and Motor Skills 2006.

  • 102062.
    Åström, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry.
    Thorell, Lars-Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Graphometric variables of one's signature: I. Basic measures2007In: Perceptual and Motor Skills, ISSN 0031-5125, E-ISSN 1558-688X, Vol. 105, no 3 I, p. 733-752Article in journal (Refereed)
    Abstract [en]

    This study focused on statistical properties and interrelationships of graphometric variables of the signatures of outpatients, 100 men and 119 women, remitted from somatic and psychiatric clinics for possible psychotherapy or for tests of IQ, personality, or brain lesions. The patients' signature on test forms were used. The type of handwriting was classified into Common, Print and Block letters, quantified in breadth, length, and area and grades of slant of minuscules ("lower-case letters") and majuscules ("upper- case"). Analysis indicated sex and age played roles in style of handwriting and size of letters, writing styles differed on most graphometric variables, and meaningful patterns of interrelationships among graphometric variables were specified by factor analysis. © Perceptual and Motor Skills 2007.

  • 102063.
    Åström, Jan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry .
    Thorell, Lars-Håkan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry . Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Psychiatry.
    Graphometric variables of one's signature: II. Correlations with measures of perception, cognitive function, and personality2008In: Perceptual and Motor Skills, ISSN 0031-5125, E-ISSN 1558-688X, Vol. 107, no 1, p. 197-221Article in journal (Refereed)
    Abstract [en]

    This study focused on interrelations between graphometric variables of the signature and measures of perception, cognitive function, and personality. Signatures from a sample of psychiatric and somatic outpatients (N=205) were analyzed into 23 graphometric variables and correlated with tests of IQ, cognitive and perceptual function, and personality. The results of a factor analysis of the graphometric, perceptual, and cognitive variables were very much like results from previous studies. Relationships with the graphometric variables can be described in five categories of intelligence, psychomotility, flexibility and speed of closure, and personality. Graphometric signs of Extraversion and Neuroticism were identified, and the two capitals in the signature indicated different psychological meanings. Measurements of the signature offered important personality information. © Perceptual and Motor Skills 2008.

  • 102064.
    Åström, Jennie
    Linköping University, Department of Social and Welfare Studies.
    Fångarna, fängelset och motståndet2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Den här uppsatsen behandlar kriminalvården utifrån fångarnas perspektiv som den skildras i tidningen Kåkbladet, som är skriven av fångar i Sverige och som även i första hand riktar sig till fångar. De intagna skribenternas upplevelser av kriminalvården läggs fram genom en diskursanalys av Kåkbladet. Analysen visar hur fångarna framställer sig själva och den personal som dagligen arbetar med dem i fängelset samt vilken bild fångarna målar upp av kriminalvården som institution. Livet i fängelset skildras i texterna som präglat av kontroll och fångarna förmedlar en upplevd maktlöshet inför sin situation. I samband med denna upplevelse skapas i texterna strategier för motmakt där fångarna genom gemensamt motstånd gör anspråk på att sätta sig upp mot kontrollen. Uppsatsen utgår från ett socialkonstruktivistiskt synsätt där den verklighet som framställs i Kåkbladet ses som en konstruktion av talet. Goffmans teori om totala institutioner används tillsammans med annan forskning om fängelset och totala institutioner som ett teoretiskt ramverk för att fördjupa förståelsen av analysresultatet.

  • 102065.
    Åström, Jennie
    Linköping University, Department of Social and Welfare Studies.
    Tvåsamhället: Om att förhålla sig till normer som skaver2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study focuses on single peoples construction of their lifes in relation to normative heterosexual coupledom. It is based on five interviews made with single women and men at the age of 24 to 51 who live by themselves. The queer theory which puts the heteronormativity in question is used as a theoretical framework. Discourse psychology functions as an analytic approach. It focuses on the use of language in the construction of reality in a world of determinant discourses. The thesis shows how the life of singles is made understandable where the interviewee´s constructs their reality by either creating their own life's as possible ways of living and distance themselves from coupledom or by striving for the twosome way of living. This is done by a construction of gender and age performance as different in the single and the twosome life. It also shows paradoxes where discourses of advantage independence meet discourses that construct twosome relationships as the only place for the development of real masculinity or of a special form of preferable femininity. The construction of gender and age as performed different in the single and the couple life provides an understanding of the interviewee's creation of self-image in relation to normative heterosexual coupledom.

  • 102066.
    Åström, Karl J.
    et al.
    Lund University, Sweden.
    Benveniste, Albert
    INRIA, France.
    Caines, Peter E.
    INRIA, France.
    Cohen, Guy
    INRIA, France.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Facing the Challenge of Computer Science in the Industrial Applications of Control1992Report (Other academic)
    Abstract [en]

    Control, signal processing, and more generally "systems" industries ignore the boundaries we have in the academic world between control, signal processing, and computer sciences. Industries think of "hardware" (electronics or computers) and "software", making little distinction between algorithms development and implementation of them. Acting as a chariman of the IFAC Technical Committee on Theory for the triennium 1990-1993, Albert Benveniste proposed in the fall of 1989 this project to investigate some fundamental questions raised by the above mentioned facts. Since CDC'90 this has been approved as a joint IEEE/CSS-IFAC project managed by the above listed group of people. A detailed progress report of the project has been written in March 20, 1991, followed by a brief update in October 19, 1991. This is summary of the conclusions of the report. Additional detailed information on the project is found in the bibliography.

  • 102067.
    Åström, Karl Johan
    et al.
    Lund Institute of Technology, Sweden.
    Borisson, U
    Gränges Data, Sweden.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Wittenmark, Björn
    Lund Institute of Technology.
    Theory and Applications of Self Tuning Regulators1977In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 13, no 5, p. 457-476Article in journal (Refereed)
    Abstract [en]

    This paper reviews work on self-tuning regulators. The regulator algorithms, their theory and industrial applications are reviewed. The paper is expository—the major ideas are covered but detailed analysis is given elsewhere.

  • 102068.
    Åström, Karsten
    Linköping University, Department of Social and Welfare Studies, Social Work. Linköping University, Faculty of Arts and Sciences.
    Parallel norm creating processes2013In: Social and Legal Norms: Towards a Socio-legal Understanding of Normativity / [ed] Matthias Baier, Farnham: Ashgate, 2013, 1Chapter in book (Other academic)
  • 102069.
    Åström, Maria
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Arts and Sciences.
    Betyg och bedömning i NO2012In: Betyg i teori och praktik: ämnesdidaktiska perspektiv på bedömning i grundskola och gymnasium / [ed] Nordgren, Kenneth, Odenstad, Christina och Samuelsson, Johan, Malmö: Gleerups Utbildning AB, 2012, 2, p. 131-140Chapter in book (Other (popular science, discussion, etc.))
  • 102070.
    Åström, Maria
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Defining Integrated Science Education and Putting It to Test2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The thesis is made up by four studies, on the comprehensive theme of integrated and subjectspecific science education in Swedish compulsory school. A literature study on the matter is followed by an expert survey, then a case study and ending with two analyses of students’ science results from PISA 2003 and PISA 2006. The first two studies explore similarities and differences between integrated and subject-specific science education, i. e. Science education and science taught as Biology, Chemistry and Physics respectively. The two following analyses of PISA 2003 and PISA 2006 data put forward the question whether there are differences in results of students’ science literacy scores due to different types of science education.

    The expert survey compares theories of integration to the Swedish science education context. Also some difference in intention, in the school case study, some slight differences in the way teachers plan the science education are shown, mainly with respect to how teachers involve students in their planning.

    The statistical analysis of integrated and subject-specific science education comparing students’ science results from PISA 2003 shows no difference between students or between schools. The analysis of PISA 2006, however, shows small differences between girls’ results with integrated and subject-specific science education both in total scores and in the three scientific literacy competencies. No differences in boys’ results are shown on different science educations.

    List of papers
    1. En Delphi-studie av initierade brukaresuppfattningar om karaktärer av integreradnaturvetenskap i senare delen av svensk grundskola
    Open this publication in new window or tab >>En Delphi-studie av initierade brukaresuppfattningar om karaktärer av integreradnaturvetenskap i senare delen av svensk grundskola
    2009 (Swedish)In: Didaktisk Tidskrift, ISSN 1101-7686, Vol. 19, no 3, p. 114-132Article in journal (Other academic) Published
    Abstract [en]

    Den här studien undersöker hur experter, väl insatta i den svenska debatten om integrerad NO uppfattar vad integrerad NO är, hur den tillämpas och vilka skäl som finns för att undervisa integrerat i NO istället för att undervisa ämnesuppdelat. Diskussionen om integrerad eller ämnesuppdelad NO hade en kulmen på 1980-talet i Sverige som gav två varianter att undervisa NO på i grundskolan, antingen som ett ämne eller som tre ämnen, biologi, kemi och fysik. Dessa varianter finns åtminstone som två likvärdiga sätt att gradera betyg på. Nu är det aktuellt att ta bort denna möjlighet att sätta NO-betyg eller biologi-, fysik- och kemibetyg, vilket gör det intressant att undersöka hur idén om vad integrerad och ämnesuppdelad NO-undervisning har för likheter och skillnader. Undersökningen är genomförd som en Delphistudie, där de tillfrågade deltagarna anonymt har värderat 30 påståenden om integrerad och ämnesuppdelad undervisning i ett första steg. Svaren sammanställdes med medelvärden och medianer och presenterades för deltagarna i en andra enkätomgång. Informanterna erbjöds möjlighet att ändra sina svar efter att ha tagit del i de övriga deltagarnas värderingar av påståendena i form av centralmått på frågorna. Resultatet av den första undersökningsomgången redovisas i tabell där informanternas sammanlagda bedömning eller skattning av påståendena redovisas. Informanternas svar diskuteras och jämförs med den teori som ursprungligen använts för att konstruera frågorna. Metodiska frågor i samband med undersökningen diskuteras också.

    Place, publisher, year, edition, pages
    Jönköping: Jönköping University Press, 2009
    National Category
    Didactics
    Identifiers
    urn:nbn:se:liu:diva-15364 (URN)
    Note

    On the day of the defence date the status of this article was "Manuscript" and the title was "En Delphistudie av initierade brukares och användares uppfattningar om karaktären av integrerad naturvetenskap i senare delen av svenska grundskola"

    Available from: 2008-11-05 Created: 2008-11-05 Last updated: 2017-12-14Bibliographically approved
    2. Integrated and subject-specific Science education: Teachers’ and students’ views
    Open this publication in new window or tab >>Integrated and subject-specific Science education: Teachers’ and students’ views
    (English)Manuscript (Other academic)
    Abstract [en]

    This study concerns the views of teachers’ and students’ regarding Science education. The teachers and students are all from four schools in the same small town in Sweden. The teachers’ views of Science lessons focused on how to plan lessons and organise content. The students’ views focused on three questions concerning the integration of science. The study is based on several data collections: interviews with and observations of teachers, a school survey and student questionnaires. The teacher interviews were analysed with regard to integrated and subject-specific Science education and the students’ questionnaires were analysed with statistical methods. The four schools in this study may be categorised as two integrated schools, one subject-specific and one mixed school. The students’ views of subjectspecific and integrated Science did not completely coincide with the teachers’ views. Teachers and students agreed on that they did integrated education in only one out of the four schools.

    Keywords
    Science education, teachers’ and students’ views, integrated and subject specific Science
    National Category
    Pedagogy
    Identifiers
    urn:nbn:se:liu:diva-15475 (URN)
    Available from: 2008-11-11 Created: 2008-11-11 Last updated: 2010-01-14Bibliographically approved
    3. Using hierarchical linear models to test differences in Swedish results from OECD's PISA 2003: Integrated and Subject-specific science education
    Open this publication in new window or tab >>Using hierarchical linear models to test differences in Swedish results from OECD's PISA 2003: Integrated and Subject-specific science education
    2007 (English)In: NorDiNa: Nordic Studies in Science Education, ISSN 1504-4556, E-ISSN 1894-1257, no 2, p. 121-131Article in journal (Refereed) Published
    Abstract [en]

    The possible effects of different organisations of the science curriculum in schools participating in PISA 2003 are tested with a hierarchical linear model (HLM) of two levels. The analysis is based on science results. Swedish schools are free to choose how they organise the science curriculum. They may choose to work subject-specifically (with Biology, Chemistry and Physics), integrated (with Science) or to mix these two. In this study, all three ways of organising science classes in compulsory school are present to some degree. None of the different ways of organising science education displayed statistically significant better student results in scientific literacy as measured in PISA 2003. The HLM model used variables of gender, country of birth, home language, preschool attendance, an economic, social and cultural index as well as the teaching organisation.

    Keywords
    science education
    National Category
    Pedagogy
    Identifiers
    urn:nbn:se:miun:diva-5130 (URN)5274 (Local ID)5274 (Archive number)5274 (OAI)
    Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2017-12-12Bibliographically approved
    4. Differences between students in Swedish compulsory schools with integrated andsubject-specific Science education in PISA 2006
    Open this publication in new window or tab >>Differences between students in Swedish compulsory schools with integrated andsubject-specific Science education in PISA 2006
    (English)Manuscript (Other academic)
    Abstract [en]

    This study is a comparison between three groups of teaching organisations in Sweden that work either with integrated Science, subject-specific Science or a mixed form of the two. Comparison is made between the students’ total Science scores in the PISA 2006 study and the three scores in student competency regarding Knowledge in Science and Knowledge about Science. This comparison is made both at the individual and school level. There are differences between students with integrated Science education and students with subjectspecific Science. These differences are found both in the total scores and in some of the subscores. An even more striking difference is found between boys and girls in the different groups. There are big differences in test scores for girls with integrated Science as compared to girls with subject-specific Science; this difference is almost nonexistent for boys. Some caution must be shown in drawing conclusions from this finding, however, since girls’ and boys’ groups differ in mean ESCS, and there are differences in the percentage of students who speak another language at home than Swedish. Some plausible explanations for the differences are discussed based on inferences from other studies.

    National Category
    Didactics
    Identifiers
    urn:nbn:se:liu:diva-15365 (URN)
    Available from: 2008-11-05 Created: 2008-11-05 Last updated: 2010-01-14Bibliographically approved
  • 102071.
    Åström, Maria
    et al.
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Arts and Sciences.
    Karl-Göran, Karlsson
    Department of Engineering, Physics and Mathematics, Mid Sweden University.
    Using hierarchical linear models to test differences in Swedish results from OECD’sPISA 2003: Integrated and subject-specific science education2007In: NorDiNa: Nordic Studies in Science Education, ISSN 1504-4556, E-ISSN 1894-1257, Vol. 3, no 2, p. 121-131Article in journal (Refereed)
    Abstract [en]

    The possible effects of different organisations of the science curriculum in schools participating in PISA 2003 are tested with a hierarchical linear model (HLM) of two levels. The analysis is based on science results. Swedish schools are free to choose how they organise the science curriculum. They may choose to work subject-specifically (with Biology, Chemistry and Physics), integrated (with Science) or to mix these two. In this study, all three ways of organising science classes in compulsory school are present to some degree. None of the different ways of organising science education displayed statistically significant better student results in scientific literacy as measured in PISA 2003. The HLM model used variables of gender, country of birth, home language, preschool attendance, an economic, social and cultural index as well as the teaching organisation.

  • 102072.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Functional brain atlas2014Conference paper (Other academic)
  • 102073.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Modelling, Simulaltion, and Visualization of Deep Brain Stimulation2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Deep brain stimulation (DBS) is an effective surgical treatment for neurological diseases such as essential tremor, Parkinsonʹs disease (PD) and dystonia. DBS has so far been used in more than 70 000 patients with movement disorders, and is currently in trial for intractable Gilles de la Tourette’s syndrome, obsessive compulsive disorders, depression, and epilepsy. DBS electrodes are implanted with stereotactic neurosurgical techniques in the deep regions of the brain. Chronic electrical stimulation is delivered to the electrodes from battery-operated pulse generators that are implanted below the clavicle.

    The clinical benefit of DBS is largely dependent on the spatial distribution of the electric field in relation to brain anatomy. To maximize therapeutic benefits while avoiding unwanted side-effects, knowledge of the distribution of the electric field in relation anatomy is essential. Due to difficulties in measuring electric fields in vivo, computerized analysis with finite element models have emerged as an alternative.

    The aim of the thesis was to investigate technical and clinical aspects of DBS by means of finite element models, simulations, and visualizations of the electric field and tissue anatomy. More specifically the effects of dilated perivascular spaces filled with cerebrospinal fluid on the electrical field generated by DBS was evaluated. A method for patient-specific finite element modelling and simulation of DBS was developed and used to investigate the anatomical distribution of the electric field in relation to clinical effects and side effects. Patient-specific models were later used to investigate the electric field in relation to effects on speech and movement during DBS in patients with PD (n=10). Patient-specific models and simulations were also used to evaluate the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the electric field during DBS. In addition, methods were developed for visualization of atlas-based and patient-specific anatomy in 3D for interpretation of anatomy, visualization of neural activation with the activating function, and visualization of tissue micro structure. 3D visualization of anatomy was used to assess electrode contact locations in relation to stimulation-induced side-effects (n=331) during DBS for patients with essential tremor (n=28). The modelling, simulation, and visualization of DBS provided detailed information about the distribution of the electric field and its connection to clinical effects and side-effects of stimulation. In conclusion, the results of this thesis provided insights that may help to improve DBS as a treatment for movement disorders as well as for other neurological diseases in the future.

    List of papers
    1. The effect of cystic cavities on deep brain stimulation in the basal ganglia: A simulation-based study
    Open this publication in new window or tab >>The effect of cystic cavities on deep brain stimulation in the basal ganglia: A simulation-based study
    Show others...
    2006 (English)In: Journal of Neural Engineering, ISSN 1741-2560, E-ISSN 1741-2552, Vol. 3, no 2, p. 132-138Article in journal (Refereed) Published
    Abstract [en]

    Although the therapeutic effect of deep brain stimulation (DBS) is well recognized, a fundamental understanding of the mechanisms responsible is still not known. In this study finite element method (FEM) modelling and simulation was used in order to study relative changes of the electrical field extension surrounding a monopolar DBS electrode positioned in grey matter. Due to the frequently appearing cystic cavities in the DBS-target globus pallidus internus, a nucleus of grey matter with and without a cerebrospinal fluid filled cystic cavity was modelled. The position, size and shape of the cyst were altered in relation to the electrode. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between grey and white matters. The cyst increased the radial extension and changed the shape of the electrical field substantially. The position, size and shape of the cyst were the main influencing factors. We suggest that cystic cavities in the DBS-target may result in closely related unexpected structures or neural fibre bundles being stimulated and could be one of the reasons for suboptimal clinical effects or stimulation-induced side effects. © 2006 IOP Publishing Ltd.

    Place, publisher, year, edition, pages
    Institute of Physics Publishing (IOPP), 2006
    National Category
    Biomedical Laboratory Science/Technology
    Identifiers
    urn:nbn:se:liu:diva-34125 (URN)10.1088/1741-2560/3/2/007 (DOI)000239673500007 ()16705269 (PubMedID)2-s2.0-33744911364 (Scopus ID)20869 (Local ID)20869 (Archive number)20869 (OAI)
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13Bibliographically approved
    2. Method for patient-specific finite element modeling and simulation of deep brain stimulation
    Open this publication in new window or tab >>Method for patient-specific finite element modeling and simulation of deep brain stimulation
    Show others...
    2009 (English)In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 47, no 1, p. 21-28Article in journal (Refereed) Published
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinsons disease. Success of DBS is highly dependent on electrode location and electrical parameter settings. The aim of this study was to develop a general method for setting up patient-specific 3D computer models of DBS, based on magnetic resonance images, and to demonstrate the use of such models for assessing the position of the electrode contacts and the distribution of the electric field in relation to individual patient anatomy. A software tool was developed for creating finite element DBS-models. The electric field generated by DBS was simulated in one patient and the result was visualized with isolevels and glyphs. The result was evaluated and it corresponded well with reported effects and side effects of stimulation. It was demonstrated that patient-specific finite element models and simulations of DBS can be useful for increasing the understanding of the clinical outcome of DBS.

    Place, publisher, year, edition, pages
    Springer, 2009
    Keywords
    Deep brain stimulation, Patient-specific, Simulation, Finite element, Glyph
    National Category
    Biomedical Laboratory Science/Technology
    Identifiers
    urn:nbn:se:liu:diva-16616 (URN)10.1007/s11517-008-0411-2 (DOI)000262483600004 ()18936999 (PubMedID)2-s2.0-58649107661 (Scopus ID)
    Note

    The original publication is available at www.springerlink.com: Mattias Åström, Ludvic U Zrinzo, Stephen Tisch, Elina Tripoliti, Marwan I Hariz and Karin Wårdell , Method for patient-specific finite element modeling and simulation of deep brain stimulation, 2009, Medical and Biological Engineering and Computing, (47), 1, 21-28. http://dx.doi.org/10.1007/s11517-008-0411-2 Copyright: Springer Science Business Media http://www.springerlink.com/

    Available from: 2009-02-07 Created: 2009-02-06 Last updated: 2017-12-14Bibliographically approved
    3. Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation
    Open this publication in new window or tab >>Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation
    Show others...
    2010 (English)In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 4, p. 224-233Article in journal (Refereed) Published
    Abstract [en]

    Background/Aims: Deep brain stimulation (DBS) is widely used to treat motor symptoms in patients with advanced Parkinson’s disease. The aim of this study was to investigate the anatomical aspects of the electric field in relation to effects on speech and movement during DBS in the subthalamic nucleus. Methods: Patient-specific finite element models of DBS were developed for simulation of the electric field in 10 patients. In each patient, speech intelligibility and movement were assessed during 2 electrical settings, i.e. 4 V (high) and 2 V (low). The electric field was simulated for each electrical setting. Results: Movement was improved in all patients for both high and low electrical settings. In general, high-amplitude stimulation was more consistent in improving the motor scores than low-amplitude stimulation. In 6 cases, speech intelligibility was impaired during high-amplitude electrical settings. Stimulation of part of the fasciculus cerebellothalamicus from electrodes positioned medial and/or posterior to the center of the subthalamic nucleus was recognized as a possible cause of the stimulation-induced dysarthria. Conclusion: Special attention to stimulation-induced speech impairments should be taken in cases when active electrodes are positioned medial and/or posterior to the center of the subthalamic nucleus.

    Keywords
    Deep brain stimulation, Dysarthria, Speech intelligibility, Parkinson’s disease, Electric field, Fasciculus cerebellothalamicus
    National Category
    Biomedical Laboratory Science/Technology
    Identifiers
    urn:nbn:se:liu:diva-58057 (URN)10.1159/000314357 (DOI)000280136100004 ()
    Note

    Original Publication: Mattias Åström, Elina Tripoliti, Mawan I. Hariz, Ludvig U. Zrinzo, Irene Martinez-Torres, Patricia Limousin and Karin Wårdell, Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation, 2010, Stereotactic and Functional Neurosurgery, (88), 4, 224-233. http://dx.doi.org/10.1159/000314357 Copyright: S. Karger AG http://www.karger.com/

    Available from: 2010-07-27 Created: 2010-07-27 Last updated: 2017-12-12Bibliographically approved
    4. Influence of heterogeneous and anisotropic tissue conductivity on electric field distribution in deep brain stimulation
    Open this publication in new window or tab >>Influence of heterogeneous and anisotropic tissue conductivity on electric field distribution in deep brain stimulation
    2012 (English)In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 50, no 1, p. 23-32Article in journal (Refereed) Published
    Abstract [en]

    The aim was to quantify the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the spatial distribution of the electric field during deep brain stimulation (DBS). Three finite element tissue models were created of one patient treated with DBS. Tissue conductivity was modelled as I) homogeneous isotropic, II) heterogeneous isotropic based on MRI, and III) heterogeneous anisotropic based on diffusion tensor MRI. Modelled DBS electrodes were positioned in the subthalamic area, the pallidum, and the internal capsule in each tissue model. Electric fields generated during DBS were simulated for each model and target-combination and visualized in 3D with isolevels at 0.20 (inner), and 0.05 V m-1 (outer). F-test and vector analysis was used for statistical evaluation of the distribution of the electric field. Heterogeneous isotropic tissue altered the spatial distribution of the electric field by up to 4% at inner, and up to 10% at outer isolevel. Heterogeneous anisotropic tissue had a larger impact on the distribution of the electric field with an influence of up to 18% and 15% at each isolevel, respectively. The influence of heterogeneous and anisotropic tissue on the electric field may be clinically relevant in anatomic regions that are functionally subdivided and surrounded by multiple fibres of passage.

    Place, publisher, year, edition, pages
    Springer, 2012
    Keywords
    Deep brain stimulation, Diffusion tensor, Finite element, Model, Simulation, Patient-specific
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-70087 (URN)10.1007/s11517-011-0842-z (DOI)000298648400003 ()
    Note

    funding agencies|Swedish Foundation for Strategic Research (SSF)||Swedish Research Council (VR)| 621-2008-3013 |Swedish Governmental Agency for Innovation Systems (VINNOVA)| 311-2006-7661 |

    Available from: 2011-08-18 Created: 2011-08-18 Last updated: 2017-12-08Bibliographically approved
    5. Stimulation-induced side effects in the posterior subthalamic area: distribution, characteristics and visualization
    Open this publication in new window or tab >>Stimulation-induced side effects in the posterior subthalamic area: distribution, characteristics and visualization
    2013 (English)In: Clinical neurology and neurosurgery (Dutch-Flemish ed. Print), ISSN 0303-8467, E-ISSN 1872-6968, Vol. 15, no 1, p. 65-71Article in journal (Refereed) Published
    Abstract [en]

    Objective: The posterior subthalamic area (PSA) is an emerging but relatively unexplored target for DBS treatment of tremor. The aim of the study was to explore the area further by evaluating the spatial distribution and the characteristics of stimulation-induced side effects in this area. Methods: Twenty-eight patients with essential tremor (ET) implanted with 33 DBS electrodes were evaluated concerning stimulation-induced side effects by testing each contact separately one year after surgery. The location of the side effects were plotted on axial slides of the Morel Stereotactic Atlas and a 3-dimensional model of the area for visualization was created. Results: Visualization of the contacts eliciting stimulation-induced side effects demonstrated that identical responses can be elicited from various points in the PSA and its vicinity. The majority of contacts inducing muscular affection and cerebellar symptoms, including dysarthria, could not be attributed to an effect on the internal capsule. Paresthesias, affecting various body parts were elicited throughout the area without a clear somatotopic pattern. Conclusion: Stimulation-induced side effects in the PSA and its vicinity are difficult to attribute to certain anatomical areas as the same response can be induced from various locations, and are thus of limited localizing value.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-70088 (URN)10.1016/j.clineuro.2012.04.015 (DOI)000312576300012 ()
    Available from: 2011-08-18 Created: 2011-08-18 Last updated: 2017-12-08Bibliographically approved
  • 102074.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Neuronmodeling and DBS electric field simulations2014Conference paper (Other academic)
  • 102075.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation BV, NL-5656 Eindhoven, Netherlands.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Martens, Hubert
    Sapiens Steering Brain Stimulation B.V., Eindhoven, The Netherlands.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Relationship between Neural Activation and Electric Field Distribution during Deep Brain Stimulation2015In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 62, no 2, p. 664-72Article in journal (Refereed)
    Abstract [en]

    Models and simulations are commonly used to study deep brain stimulation (DBS). Simulated stimulation fields are often defined and visualized by electric field isolevels or volumes of tissue activated (VTA). The aim of the present study was to evaluate the relationship between stimulation field strength as defined by the electric potential V, the electric field E, and the divergence of the electric field ∇(2) V, and neural activation. Axon cable models were developed and coupled to finite-element DBS models in three-dimensional (3-D). Field thresholds ( VT , ET, and ∇(2) VT ) were derived at the location of activation for various stimulation amplitudes (1 to 5 V), pulse widths (30 to 120 μs), and axon diameters (2.0 to 7.5 μm). Results showed that thresholds for VT and ∇(2) VT were highly dependent on the stimulation amplitude while ET were approximately independent of the amplitude for large axons. The activation field strength thresholds presented in this study may be used in future studies to approximate the VTA during model-based investigations of DBS without the need of computational axon models.

  • 102076.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Computational analysis of the electric field during deep brain stimulation (oral, invited)2010Conference paper (Refereed)
  • 102077.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Software for patient-specific modeling and simulation of deep brain stimulation (poster)2011Conference paper (Other academic)
  • 102078.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Johansson, Johannes
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Hariz, Marwan
    Institute of Neurology London.
    Eriksson, Ola
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    The effect of cystic cavities on deep brain stimulation in the basal ganglia: A simulation-based study2006In: Journal of Neural Engineering, ISSN 1741-2560, E-ISSN 1741-2552, Vol. 3, no 2, p. 132-138Article in journal (Refereed)
    Abstract [en]

    Although the therapeutic effect of deep brain stimulation (DBS) is well recognized, a fundamental understanding of the mechanisms responsible is still not known. In this study finite element method (FEM) modelling and simulation was used in order to study relative changes of the electrical field extension surrounding a monopolar DBS electrode positioned in grey matter. Due to the frequently appearing cystic cavities in the DBS-target globus pallidus internus, a nucleus of grey matter with and without a cerebrospinal fluid filled cystic cavity was modelled. The position, size and shape of the cyst were altered in relation to the electrode. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between grey and white matters. The cyst increased the radial extension and changed the shape of the electrical field substantially. The position, size and shape of the cyst were the main influencing factors. We suggest that cystic cavities in the DBS-target may result in closely related unexpected structures or neural fibre bundles being stimulated and could be one of the reasons for suboptimal clinical effects or stimulation-induced side effects. © 2006 IOP Publishing Ltd.

  • 102079.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Johansson, Johannes
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Modeling and simulation of electric fields generated by brain stimulation electrodes: the effect of cystic cavities in the basal ganglia2005In: Proceedings from the International IEEE EMBS Conference on Neural Engineering, IEEE , 2005, p. 198-201Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an effective method for managing movement disorders. A small electrode is implanted in the basal ganglia and an electric potential is applied to one or more active elements of the electrode in order to simulate the neurons in the surrounding tissue. The fundamental understanding of the mechanisms responsible for the therapeutic DBS effects is unknown. A method to increase the knowledge is to use computer simulations. In this study the finite element method has been used for investigation of relative changes of the electrical field extension surrounding a monopolar DBS-electrode positioned in gray matter. Due to the frequently appearing cystic cavities in globus pallidus and putamen a nucleus of gray matter with and without a cerebrospinal fluid filled cystic cavity was modeled. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between gray and white matter. The cyst increased the radial extension and changed the shape of the field. This may result in closely related unexpected structures being stimulated and could be one of the reasons of reported postoperative complications.

  • 102080.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Lemair, Jean-Jaques
    Hôpital Gabriel Montpied, Service de Neurochirurgie, Clermont-Ferrand, France.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    The influence of brain tissue heterogeneity and anisotropy on deep brain stimulation in the subhalamic nucleus2009Conference paper (Refereed)
  • 102081.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Lemaire, Jean-Jacques
    Clermont Université, Université d'Auvergne, EA 3295, Equipe de recherche en signal et imagerie médicale, Image- Guided Clinical Neuroscience and Connectomics (IGCNC), BP 10448, F-63000 Clermont-Ferrand, France/CHU Clermont-Ferrand, Service de Neurochirurgie, F-63003 Clermont-Ferrand, France.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Influence of heterogeneous and anisotropic tissue conductivity on electric field distribution in deep brain stimulation2012In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 50, no 1, p. 23-32Article in journal (Refereed)
    Abstract [en]

    The aim was to quantify the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the spatial distribution of the electric field during deep brain stimulation (DBS). Three finite element tissue models were created of one patient treated with DBS. Tissue conductivity was modelled as I) homogeneous isotropic, II) heterogeneous isotropic based on MRI, and III) heterogeneous anisotropic based on diffusion tensor MRI. Modelled DBS electrodes were positioned in the subthalamic area, the pallidum, and the internal capsule in each tissue model. Electric fields generated during DBS were simulated for each model and target-combination and visualized in 3D with isolevels at 0.20 (inner), and 0.05 V m-1 (outer). F-test and vector analysis was used for statistical evaluation of the distribution of the electric field. Heterogeneous isotropic tissue altered the spatial distribution of the electric field by up to 4% at inner, and up to 10% at outer isolevel. Heterogeneous anisotropic tissue had a larger impact on the distribution of the electric field with an influence of up to 18% and 15% at each isolevel, respectively. The influence of heterogeneous and anisotropic tissue on the electric field may be clinically relevant in anatomic regions that are functionally subdivided and surrounded by multiple fibres of passage.

  • 102082.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Medtronic, Sweden; Medtronic, Netherlands.
    Samuelsson, Jennifer
    Umea Univ, Sweden.
    Roothans, Jonas
    Medtronic, Sweden; Medtronic, Netherlands.
    Fytagoridis, Anders
    Umea Univ, Sweden; Karolinska Inst, Sweden.
    Ryzhkov, Maxim
    Medtronic, Sweden; Medtronic, Netherlands.
    Nijlunsing, Rutger
    Medtronic, Sweden; Medtronic, Netherlands.
    Blomstedt, Patric
    Umea Univ, Sweden.
    Prediction of Electrode Contacts for Clinically Effective Deep Brain Stimulation in Essential Tremor2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 5, p. 281-288Article in journal (Refereed)
    Abstract [en]

    Background/Aim: Deep brain stimulation (DBS) is an established neurosurgical treatment that can be used to alleviate symptoms in essential tremor (ET) and other movement disorders. The aim was to develop a method and software tool for the prediction of effective DBS electrode contacts based on probabilistic stimulation maps (PSMs) in patients with ET treated with caudal zona incerta (cZi) DBS. Methods: A total of 33 patients (37 leads) treated with DBS were evaluated with the Essential Tremor Rating Scale (ETRS) 12 months after surgery. In addition, hand tremor and hand function (ETRS items 5/6 and 11-14) were evaluated for every contact during stimulation with best possible outcome without inducing side effects. Prediction of effective DBS electrode contacts was carried out in a retrospective leave-one-out manner based on PSMs, simulated stimulation fields, and a scoring function. Electrode contacts were ranked according to their likelihood of being included in the clinical setting. Ranked electrode contacts were compared to actual clinical settings. Results: Predictions made by the software tool showed that electrode contacts with rank 1 matched the clinically used contacts in 60% of the cases. Contacts with a rank of 1-2 and 1-3 matched the clinical contacts in 83 and 94% of the cases, respectively. Mean improvement of hand tremor and hand function was 79 +/- 21% and 77 +/- 22% for the clinically used and the predicted electrode contacts, respectively. Conclusions: Effective electrode contacts can be predicted based on PSMs in patients treated with cZi DBS for ET. Predictions may in the future be used to reduce the number of clinical assessments that are carried out before a satisfying stimulation setting is defined. (C) 2018 S. Karger AG, Basel

  • 102083.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tisch, Stephen
    Institute of Neurology University College, London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology University College, London, UK.
    Tripoliti, Elina
    University of Neurology University College, London, UK.
    Hariz, Marwan I.
    Department of Neurosurgery University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    A model-Based analysis of deep brain stimulation2007Conference paper (Other academic)
    Abstract [en]

      

  • 102084.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, E
    n/a.
    Hariz, M I
    n/a.
    Zrinzo, L U
    n/a.
    Martinez-Torre, I
    n/a.
    Limousin, P
    n/a.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Swedish Movement Disorder Society, Umeå 15-16 october, 20092009In: The electric field during DBS, 2009Conference paper (Other academic)
  • 102085.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, E.
    Institute of Neurology University College London.
    Zrinzo, U.
    Institute of Neurology University College London.
    Marinez-Torres, I.
    Institute of Neurology University College London.
    Limousin, P.
    Institute of Neurology University College London.
    Hariz, M. I.
    Institute of Neurology University College London.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Voltage steering to control deep brain stimulation-induced speech deficits2008In: XVIII Congress of the European Society for Stereotactic and Functional Neurosurgery,2008, 2008Conference paper (Other academic)
  • 102086.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, Elina
    University College, London.
    Hariz, Mawan I.
    University Hospital, Umeå .
    Zrinzo, Ludvig U.
    University College, London.
    Martinez-Torres, Irene
    University College, London.
    Limousin, Patricia
    University College, London.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation2010In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 4, p. 224-233Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Deep brain stimulation (DBS) is widely used to treat motor symptoms in patients with advanced Parkinson’s disease. The aim of this study was to investigate the anatomical aspects of the electric field in relation to effects on speech and movement during DBS in the subthalamic nucleus. Methods: Patient-specific finite element models of DBS were developed for simulation of the electric field in 10 patients. In each patient, speech intelligibility and movement were assessed during 2 electrical settings, i.e. 4 V (high) and 2 V (low). The electric field was simulated for each electrical setting. Results: Movement was improved in all patients for both high and low electrical settings. In general, high-amplitude stimulation was more consistent in improving the motor scores than low-amplitude stimulation. In 6 cases, speech intelligibility was impaired during high-amplitude electrical settings. Stimulation of part of the fasciculus cerebellothalamicus from electrodes positioned medial and/or posterior to the center of the subthalamic nucleus was recognized as a possible cause of the stimulation-induced dysarthria. Conclusion: Special attention to stimulation-induced speech impairments should be taken in cases when active electrodes are positioned medial and/or posterior to the center of the subthalamic nucleus.

  • 102087.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, Elina
    Institute of Neurology, Queen Square, University College London, UK.
    Martinez-Torres, Irene
    Institute of Neurology, Queen Square, University College London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology, Queen Square, University College London, UK.
    Limousin, Patricia
    Institute of Neurology, Queen Square, University College London, UK.
    Hariz, Marwan I.
    Institute of Neurology, Queen Square, University College London, UK; Dept of Neurosurgery, University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Patient-specific models and simulations of deep brain stimulation for postoperative follow-up2009In: World Congress on Medical Physics and Biomedical Engineering / [ed] Olaf Dössel and Wolfgang C. Schlegel, Springer , 2009, p. 331-334Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinson’s disease (PD). The success of DBS is highly dependent on electrode location and electrical parameter settings. In this study patient-specific computer models of DBS were used for postoperative follow-up in three PD patients who suffered from stimulation induced hypomania, dysarthria, and uncontrollable laughter respectively. The overall aim of the study was to relate the anatomical aspect of the electric field to the effects and side effects of stimulation. The simulations showed the anatomical distribution of the electric field for all the patients and the results were in agreement with previous reports regarding these side effects of stimulation. It was demonstrated that patient-specific models and simulations of DBS may be useful for postoperative follow-up of DBS.

  • 102088.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, Elina
    Institute of Neurology University College London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology University College London, UK.
    Martinez-Torres, Irene
    Institute of Neurology University College London, UK.
    Limousin, Patricia
    Institute of Neurology University College London, UK.
    Hariz, Marwan I.
    Institute of Neurology University College London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Voltage steering to control the effects and side effects of deep brain stimulation2008Conference paper (Other academic)
  • 102089.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, Elina
    Institute of Neurology University College, London, UK.
    Zrinzo, Ludvic U
    Institute of Neuroligy University College, London, UK.
    Tisch, Stephen
    Institute of Neurology University College, London, UK.
    Martinez-Torres, Irene
    Institute of Neurology University College, London, UK.
    Limousin, Patricia
    Institute of Neurology University College, London, UK.
    Hariz, Marwan I.
    Department of Neurosurgery University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Effects of bilateral subthalamic nucleus deep brain stimulation on speech intelligibillity and movement: A model-based case stydy.2007In: XVII WFN World Congress on Parkinson´s disease and related disorders,2007, 2007Conference paper (Other academic)
    Abstract [en]

      

  • 102090.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    U. Zrinzo, Ludvic
    Institute of Neurology, Queen Square, London, UK.
    I. Hariz, Marwan
    Inst. för Neurokirurgi Norrlands universitetssjukhus, Umeå samt Institute of Neurology, Queen Square, London, UK.
    Tisch, Stephen
    Institute of Neurology, Queen Square, London, UK.
    Limousin, Patricia
    Institute of Neurology, Queen Square, London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Patientspecifik modellering och simulering av djup hjärnstimulering2006In: Medicinteknikdagarna 2006,2006, 2006Conference paper (Other academic)
  • 102091.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zrinzo, L.U.
    Institute of Neurology Queen square, London, UK.
    Hariz, Marwan
    Institute of Neurology Queen square, London, UK.
    Tisch, Stephen
    Institute of Neurology Queen Square, London, UK.
    Limousin, Patricia
    Institute of Neurology Queens Square, London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Patient specific modelling and simulation of deep brain stimulation: A method for pre- and postoperative investigations2006Conference paper (Other academic)
  • 102092.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zrinzo, Ludvic U
    University College London.
    Tisch, Stephen
    Linköping University, The Institute of Technology.
    Tripoliti, Elina
    University College London.
    Hariz, Marwan I
    University College London.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Method for patient-specific finite element modeling and simulation of deep brain stimulation2009In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 47, no 1, p. 21-28Article in journal (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinsons disease. Success of DBS is highly dependent on electrode location and electrical parameter settings. The aim of this study was to develop a general method for setting up patient-specific 3D computer models of DBS, based on magnetic resonance images, and to demonstrate the use of such models for assessing the position of the electrode contacts and the distribution of the electric field in relation to individual patient anatomy. A software tool was developed for creating finite element DBS-models. The electric field generated by DBS was simulated in one patient and the result was visualized with isolevels and glyphs. The result was evaluated and it corresponded well with reported effects and side effects of stimulation. It was demonstrated that patient-specific finite element models and simulations of DBS can be useful for increasing the understanding of the clinical outcome of DBS.

  • 102093.
    Åström, Meriam Aneq
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Brudin, Lars
    Kalmar County Hospital, Sweden .
    Nylander, Eva
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Evaluation of right and left ventricular function using speckle tracking echocardiography in patients with arrhythmogenic right ventricular cardiomyopathy and their first degree relatives2012In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 10, no 37Article in journal (Refereed)
    Abstract [en]

    Introduction and aim: The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC. Methods and results: Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32-70) years old, nineteen male first degree relatives 29 (19-73) y.o. and twenty-two healthy male volunteers 36 (24-66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index less thanl while patients with abnormal ventricles had an index between 1-4. Some of the first degree relatives deviated from the normal pattern. Conclusion: Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers.

  • 102094.
    Åström, Therese
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Betydelsen av skogskontinuitet och egenskaper hos gran för förekomst av Lecanactis abietina2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Skyddandet av gamla skogar med höga naturvärden är en viktig del i bevarandet av den biologiska mångfalden. För att kunna lokalisera och kvalitetsbedöma skogar med höga naturvärden används signalarter. En av dessa signalarter är Lecanactis abietina, gammelgranslav. Syftet med denna studie är att identifiera vilka faktorer som påverkar förekomst av signalarten L. abietina och täckningsgraden av apothecier. Studien utfördes i Ycke, Ullstämma och Säby Västerskog, vilka är naturreservat av olika ålder i Linköpings kommun, Östergötlands län. I de studerade områdena undersöktes samtliga granar med en diameter över 5 cm. Granarnas diameter och skuggning mättes, vid förekomst av L. abietina undersöktes förekomsten av apothecier, lavens täckningsgrad, maxhöjd och i vilka väderstreck laven förekom. Ett mindre urval av granarna borrades och ålderbestämdes. Resultatet visar att faktorerna som påverkar förekomst av L. abietina och täckningsgraden av apothecier främst är, skoglig kontinuitet i området, samt granarnas diameter och ålder. Resultaten från denna studie styrker användandet av L. abietina som lämplig indikatorart i Östergötland då lavens förekomst och spridning tydligt  speglade skogens kontinuitet (störst förekomst i de äldsta reservaten) och trädens egenskaper. Studien visar även att enbart förekomst inte räcker för att påvisa skog med höga naturvärden, utan de viktigaste faktorerna var förekomst av fertil lav, lavens täckningsgrad och frekvens på granar. Studien visar även att bevarandet av skogar med lång kontinuitet och förekomst av stora och gamla träd är viktigt för förekomsten av L. abietina.

  • 102095.
    Åström Åberg, Fabian
    Linköping University, Department of Computer and Information Science.
    Dry-run med hjälp av union mount2015Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Många avancerade och komplexa system används idag run-tom i världen och flera av dem är väldigt viktiga att de fungerar och fortsätter göra det. För att inte förstöra dessa system så kan en dry-run användas om någonting behöver uppdateras eller ändras. Med dry-run menas att en ändring aldrig händer men att resultaten av ändringen kan visas på en skärm eller förmedlas på något sätt. Det här arbetet undersöker om unionmount är en bra lösning för att implementera detta. Arbetetvisar att det finns möjligheter för att implementeras men det finns en del problem som behöver lösas. Detta kan också bero på vilket system man vill implementera det i.

  • 102096.
    Åström-Lilja, Cecilia
    et al.
    Lund.
    Mercke Odeberg, Johanna
    Lund.
    Ekman, Elisbet
    Lund.
    Hägg, Staffan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Pharmacology . Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Drug-induced torsades de pointes: A review of the Swedish pharmacovigilance database2008In: Pharmacoepidemiology and Drug Safety, ISSN 1053-8569, E-ISSN 1099-1557, Vol. 17, no 6, p. 587-592Article in journal (Refereed)
    Abstract [en]

    Aim: To describe spontaneously reported cases of torsades de pointes (TdP) in Sweden and to investigate if this adverse drug reaction (ADR) was labelled in the summary of product characteristics (SPC) for the drugs implicated. Methods: Reported cases of TdP 1991-2006 were identified and evaluated with regard to drug use and other possible risk factor. Results: Among a total of 61 788 ADRs, 88 cases of TdP were identified. In these cases, 27 different suspected drugs were implicated. Cardiac drugs were involved in most reports (74%, 65/88), with sotalol being the most frequently suspected drug (57%, 58/88). In addition to drug treatment two or more established risk factors were present in 85% of the cases (75/88). Heart disease (90%, 79/88) was the most common risk factor followed by age over 65 years (72%, 63/88) and female gender (70%, 62/88). TdP or QT prolongation were labelled in the SPC for 33% (9/ 27) of the drugs implicated in the 88 cases. However, supporting evidence for an association was found elsewhere in 56% (15/27) for the different drugs implicated in the reports. Although citalopram was the third most common suspected drug in the reports (10%, 9/88), TdP was not listed in the SPC. Conclusion: TdP is a rarely reported ADR. Several risk factors are often present. In two thirds of the drugs implicated in the reports neither TdP nor QT prolongation was labelled in the SPC. Further investigations are needed regarding the association between citalopram and TdP. Copyright © 2008 John Wiley & Sons, Ltd.

  • 102097.
    Åvall Lundqvist, Elisabeth
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Paradigmskifte för gynekologisk cancer2015In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 112, no 50, p. 2271-Article in journal (Refereed)
    Abstract [sv]

    Med ökad förståelse för bakomliggande mekanismer har ett genombrott skett vad gäller behandling och förståelse av gynekologisk cancer. I år godkändes den första målriktade behandlingen vid gynekologisk cancer, och därmed blir individualiserad behandling en realitet.

  • 102098.
    Åvall Lundqvist, Elisabeth
    Department of Oncology, Radiumhemmet, Karolinska University Hospital, Stockholm, Sweden.
    Principles of chemotherapy.2012In: International Journal of Gynecology & Obstetrics, ISSN 0020-7292, E-ISSN 1879-3479, Vol. 119, no Suppl 2, p. 151-154Article in journal (Refereed)
  • 102099.
    Åvall Lundqvist, Elisabeth
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Department of Obstetrics and Gynecology, Karolinska Hospital, Stockholm, Sweden.
    Blad, E
    Xiao, L
    Sjövall, K
    Eneroth, P
    Pretreatment serum levels of C-reactive protein, alpha 1-antitrypsin, haptoglobin, alpha 1-acid glycoprotein and tissue polypeptide antigen in cervical carcinoma.1991In: European journal of gynaecological oncology, ISSN 0392-2936, Vol. 12, no 5, p. 375-383Article in journal (Refereed)
    Abstract [en]

    In order to evaluate the potentially additive information of some acute phase reactants to that provided by a general tumour marker, pretreatment concentrations of C-reactive protein, alpha 1-antitrypsin, haptoglobin, alpha 1-acid glycoprotein and tissue polypeptide antigen were determined in serum from healthy women, patients with dysplasia/or carcinoma in situ and patients with primary cervical carcinoma. Specificity varied from 95-100% and sensitivity from 16-29%. A correlation with clinical stage was found for all analytes except for alpha 1-antitrypsin. The latter was the most frequently elevated analyte in early Stages (11/43 in Stage Ib/IIa) and uniquely elevated in 7 cancer patients. Although tissue polypeptide antigen predominantly signaled in advanced stages, 3 women in early stages had elevated tissue polypeptide antigen levels. One of these women died and she was also the only woman with raised alpha 1-antitrypsin who died. It is discussed whether elevated tissue polypeptide levels might represent an unfavourable sign for the individual and if alpha 1-antitrypsin is a favourable sign in early stages of cervical carcinoma. C-reactive protein results were obscured in early stages of disease by the presence of intercurrent illness and the results were regarded as inconclusive. Haptoglobin and alpha 1-acid glycoprotein concentrations provided no additional information to serum alpha 1-antitrypsin levels. However, haptoglobin was elevated in 64% (36/56) of the women with dysplasia/carcinoma in situ of the cervix uteri.

  • 102100.
    Åvall Lundqvist, Elisabeth
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Fujiwara, Keiichi
    Saitama Medical University, Japan.
    Seoud, Muhieddine
    Amer University of Beirut, Lebanon.
    Principles of chemotherapy2015In: International Journal of Gynecology & Obstetrics, ISSN 0020-7292, E-ISSN 1879-3479, Vol. 131, p. S146-S149Article in journal (Refereed)
    Abstract [en]

    n/a

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