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  • 1. Adolfsson, R.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Minnesstörningar vid alkoholmissbruk ("Memory disturbances following alcohol abuse")1987In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 84, p. 3923-3926Article in journal (Refereed)
  • 2.
    Birberg Thornberg, Ulrika
    et al.
    Linköping University, Department of Behavioural Sciences.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Gustafsson, P.
    Duchen, K.
    Nutrition and cognitive development2002In: Områdesgruppen för utvecklingspsykologi och neuropsykologi,2002, 2002Conference paper (Other academic)
  • 3.
    Birberg Thornberg, Ulrika
    et al.
    Linköping University, Department of Behavioural Sciences. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Gustafsson, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Child and Adolescent Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Child and Adolescent Psychiatry.
    Duchén, Karel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Nutrition and theory of mind: The role of polyunsaturated fatty acids (PUFA) in the development of theory of mind2006In: Prostaglandins, Leukotrienes and Essential Fatty Acids, ISSN 0952-3278, E-ISSN 1532-2823, Vol. 75, no 1, p. 33-41Article in journal (Refereed)
    Abstract [en]

    Breast-milk provides nutrients required for the development of the brain. n-6 and n-3 long-chain polyunsaturated fatty acids (LCPUFAs) have been suggested to be particularly involved. In this study levels of fatty acids in breast-milk were examined in relation to theory of mind (ToM) (n=13) and WISC-III (n=22) in six-year-old children. ToM tasks comprised four illustrated stories with questions about emotional (sad) events. Single polyunsaturated fatty acids (PUFA) were estimated as well as ratios between different fatty acids in order to describe putative associations between PUFA and psychological measures. Results show correlations between both ToM and WISC-III with single n-6 PUFA and the ratios DHA/AA and DHA/DPA. The correlations remained when socio-demographic factors were statistically controlled for. The positive findings related to the n-6 and n-3 LCPUFAs corroborate previous findings related to child cognitive development. © 2006 Elsevier Ltd. All rights reserved.

  • 4. Bäckman, L.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Effects of word fragment completion on free recall: A selective improvement of older adults1987In: Comprehensive gerontology. Section B, Behavioural, social and applied sciences, ISSN 0902-008X, Vol. 1, p. 22-30Article in journal (Refereed)
  • 5. Bäckman, L.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Episodic remembering in young adults, 73 year olds, and 82 year olds1986In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 27, p. 320-325Article in journal (Refereed)
  • 6. Bäckman, L.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    The relation between level of general knowledge and feeling-of-knowing: An adult age-study1985In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 26, p. 249-258Article in journal (Refereed)
  • 7. Börjesson, A.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Adolfsson, R.
    Rönnlund, M.
    Nilsson, L-G.
    Linopiridine (DuP 996): Cholinergic treatment of older adults using a successive test paradigm1999In: Neuropsychobiology, ISSN 0302-282X, E-ISSN 1423-0224, Vol. 40, p. 78-85Article in journal (Refereed)
  • 8. Cruts, M.
    et al.
    Backhovens, H.
    Van Gassen, G.
    Theuns, J.
    Wang, Sheng-Ye
    Wehnert, A.
    van Duijn, C.M.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Hofman, A.
    Adolfsson, R.
    Martin, J-J.
    Van Broeckhoven, C.
    Mutation analysis of the chromosome 14q24.3 dihydrolipoyl succinyltransferase (DLST) gene in patients with early-onset Alzheimers disease1995In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 199, p. 73-77Article in journal (Refereed)
  • 9. Dubuc, S.
    et al.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Lalonde, R.
    Department of Psychology, Rouen University, France.
    Determinants of capacious memory: A process-dissociation and experiential approach2005In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 46, no 3, p. 217-227Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to delineate some important circumstances where exceptionally good memory performance, or capacious memory occurs. A further aim is to study memory processes involved in this memory phenomenon. In a first experiment, participants looked through two series of pictures differing in number and were evaluated in two-alternative forced-choice and yes-no recognition memory tasks combined in a process-dissociation procedure. Moreover, participants were asked to provide remember and know responses to tap recollective experience. The results as to forced-choice recognition task accuracy and according to process-dissociation procedure estimates were replicated in a second experiment with a more intrinsic contextual manipulation, and in a third, forgetting experiment. In addition to replicating previous findings, the results show (a) that capacious memory is associated with strong feelings of recollection, and (b) that familiarity (in terms of the process-dissociation framework) contributes to this phenomenon. © 2005 The Scandinavian Psychological Associations/Blackwell Publishing Ltd.

  • 10. Dubuc, S.
    et al.
    Lalonde, R.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Capacious Memory2004In: Conference of the French Psychological Association,2004, 2004Conference paper (Other academic)
  • 11.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Fatigue and cognitive effort in multiple sclerosis: an fMRI study2011Conference paper (Other academic)
    Abstract [en]

    Despite recent advances in therapy and diagnosis, fatigue remains a mayor challenge in multiple sclerosis (MS).  To further the understanding of the neural underpinnings of fatigue, we undertook a study using functional magnetic resonance imaging (fMRI) to investigate neural networks that may be affected by MS-related fatigue. Twelve MS patients and 12 age- and sex matched controls were administered the Fatigue Impact Scale (FIS) to assess clinically significant fatigue, and underwent a neuropsychological examination. The participants performed a working memory task (Daneman’s  ‘Reading Span’ task) while being monitored by means of a 1.5 T Philips Achieva MR scanner. We have previously shown that this task triggers an executive network comprising frontal and parietal areas typically involved in working memory. In addition, the task engages a core network involving the anterior insula and the anterior cingulate cortex.  This latter network may be implicated in allocation of mental resources and monitoring of the present state of the individual. There were two main findings. MS participants evidenced less activation than controls in the anterior cingulate and the left parietal cortex (Brodmann area 7) and more activation in left hemisphere language areas as well as the anterior insula. The second main finding was that clinical ratings of fatigue were strongly correlated with activity in wide areas of the core network, as well as posterior language areas. We take this finding to indicate that fatigue is related to compensatory involvement of the core network, and that excess activity in the core network possibly could be used as an objective marker of fatigue in MS.

  • 12.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. University West, Trollhättan, Sweden.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care in Linköping.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Thalamo-striato-cortical determinants to fatigue in multiple sclerosis2013In: Brain and Behavior, ISSN 2162-3279, E-ISSN 2162-3279, Vol. 3, no 6, p. 715-728Article in journal (Refereed)
    Abstract [en]

    Background

    The aim was to explore the thalamo-striato-cortical theory of central fatigue in multiple sclerosis (MS) patients with self-reported fatigue. If the theory correctly predicted fatigue based on disruptions of the thalamo-striato-cortical network, we expected altered brain activation in this network in MS participants while performing a complex cognitive task that challenged fatigue.

    Methods

    MS participants with self-reported fatigue were examined by functional magnetic resonance imaging (fMRI) during the performance of a complex working memory task. In this task, cognitive effort was challenged by a parametric design, which modeled the cerebral responses at increasing cognitive demands. In order to explore the theory of central fatigue in MS we also analyzed the cerebral responses by adding perceived fatigue scores as covariates in the analysis and by calculating the functional connectivity between regions in the thalamo-striatocortical network. The main findings were that MS participants elicited altered brain responses in the thalamo-striato-cortical network, and that brain activation in the left posterior parietal cortex and the right substantia nigra was positively correlated to perceived fatigue ratings. MS participants had stronger cortical-to-cortical and subcortical-to-subcortical connections, whereas they had weaker cortical-to-subcortical connections.

    Conclusions

    The findings of the present study indicate that the thalamo-striato-cortical network is involved in the pathophysiology of fatigue in MS, and provide support for the theory of central fatigue. However, due to the limited number of participants and the somewhat heterogeneous sample of MS participants, these results have to be regarded as tentative, though they might serve as a basis for future studies.

  • 13.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Cognition, Development and Disability. Linköping University, Faculty of Arts and Sciences.
    Aberrant brain activation in the core control network for cognitive function in MS2011Conference paper (Other academic)
    Abstract [en]

    Purpose: The purpose of this study was to investigate if patients with multiple sclerosis (MS) and fatigue have aberrant brain activation in the anterior insular cortex (AIC) and the anterior cingulate cortex (ACC), which are regions in the brain that are suggested to be a core network for cognitive control (Cole and Schneider, 2007; Sridharan et al., 2008).

     Materials and Methods: Twelve patients with MS and eleven healthy controls were examined with functional Magnetic Resonance Imaging (fMRI) while performing a complex working memory task. The task was to indicate if words presented in video goggles had appeared in previously presented sentences. Axial blood oxygen level dependent (BOLD) images were analyzed with SPM8 software. Images were realigned for movement correction, normalised to standard brain template, and smoothed with 8mm Gaussian kernel. We used a parametric contrast that tapped brain activation as a function of difficulty level of the task, i.e. words presented after 1, 2, 3, or 4 consecutive sentences.

    Results: Healthy controls elicited more activation in the left superior parietal lobe (p<0.001 family wise error (FWE) corrected for multiple comparisons), the right caudate head (p=0.002), and ACC (p=0.004) compared to MS patients. The MS patients had more activity in the left and right inferior parietal lobe (p=0.001 and p=0.029, respectively). In addition, in a region of interest analysis the MS patients had more activation in the left dorsal and ventral AIC (p=0.011 and p=0.009, respectively). The figure shows brain activation at working memory across both healthy controls and MS.

     Conclusion: MS patients elicited, as predicted, aberrant activation in the AIC-ACC network in that they had activation depletion in ACC and increased activity in the left AIC. It has recently been proposed that the AIC engenders awareness and the ACC engenders volitional action (Craig, 2009). The abnormal activation in this region could therefore explain the frequent symptoms of fatigue and cognitive impairment in MS.

     Clinical Relevance statement: Cognitive impairment occurs in 40-70% of individuals with MS and the patophysiology is unknown. Increased knowledge might contribute to novel strategies for symptomatic treatment.

  • 14.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Hallböök, Tove
    Sahlgrenska Academy, University of Gothenburg, Sweden.
    Szakacs, Attila
    Sahlgrenska Academy, University of Gothenburg. Sweden; Halmstad County Hospital, Sweden.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Functional magnetic resonance imaging in narcolepsy and the Kleine–Levin syndrome2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, no 105Article in journal (Refereed)
    Abstract [en]

    This work aims at reviewing the present state of the art when it comes to understanding the pathophysiology of narcolepsy and the Kleine–Levin syndrome (KLS) from a neuroimaging point of view. This work also aims at discussing future perspectives of functional neuroimaging in these sleep disorders. We focus on functional magnetic resonance imaging (fMRI), which is a technique for in vivo measurements of brain activation in neuronal circuitries under healthy and pathological conditions. fMRI has significantly increased the knowledge on the affected neuronal circuitries in narcolepsy and the Kleine–Levin syndrome. It has been shown that narcolepsy is accompanied with disturbances of the emotional and the closely related reward systems. In the Kleine Levin syndrome, fMRI has identified hyperactivation of the thalamus as a potential biomarker that could be used in the diagnostic procedure. The fMRI findings in both narcolepsy and the Kleine–Levin syndrome are in line with previous structural and functional imaging studies. We conclude that fMRI in combination with multi-modal imaging can reveal important details about the pathophysiology in narcolepsy and the Kleine–Levin syndrome. In the future, fMRI possibly gives opportunities for diagnostic support and prediction of treatment response in individual patients.

  • 15.
    Engström, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    An fMRi investigation of mental effort in a complex working memory task2010In: 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona 2010: Abstract No 1116, 2010Conference paper (Other academic)
    Abstract [en]

     

    A fundamental component of attention and working memory is the ability to allocate sufficient amount of mental resources to ongoing activity. Despite the fact that ’effort’ is a key ingredient to current theories about attention and memory, little is known about the brain’s regulation of cognitive effort. In this fMRI study, we employed the momentous Daneman reading span task (Daneman & Carpenter, 1980) to induce cognitive effort. We have previously used complex working memory tasks to study deficits with respect to effortful processing in patients with sleep disorders (Engström, et al., 2009). We have noted profound involvement of the anterior cingulate cortex in relation to cognitive effort. We now wish to corroborate this finding in a larger group of healthy participants.

     

     

  • 16.
    Engström, Maria
    et al.
    Linköping University. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Karlsson, Thomas
    Linköping University. Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Disorganised working memory functional connectivity in periodic hypersomnia2010In: 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona 2010: 16th Annual Meeting of the Organization for Human Brain Mapping, Abstract No 1771, 2010Conference paper (Other academic)
    Abstract [en]

    The Kleine–Levin Syndrome (KLS) is a rare but relatively well-defined disorder characterised by excessive sleep periods (periodic hypersomnia) associated with cognitive deficits and behavioural disturbances such as binge eating and hypersexuality [1]. The etiology of KLS is unknown and several neuroimagning methods have been applied to investigate the neural corrlates to KLS. A functional Magnetic Resonance Imaging (fMRI) study by us implicated hyperactivity in the thalamus and hypoactivity in the anterior cingulate cortex and the right anterior insula in a working memory task [2], which imply the involvement of a recently proposed anterior cingulate-insular control network in KLS [3]. As we expected less coherent organisation in KLS, we compared the connectivity of the anterior cingulate-insular and thalamic (AIT) network and the well-known, working memory-related, dorsal attention network (involving the dorsolateral prefrontal cortex and parietal areas) between KLS and controls.

  • 17.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Abnormal thalamic activation and complex working memory in Kleine-Levin Syndrome2013Conference paper (Other academic)
  • 18.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Reduced thalamic and pontine connectivity in Kleine–Levin syndrome2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, no 42Article in journal (Refereed)
    Abstract [en]

    The Kleine–Levin syndrome (KLS) is a rare sleep disorder, characterized by exceptionally long sleep episodes. The neuropathology of the syndrome is unknown and treatment is often inadequate. The aim of the study was to improve understanding of the underlying neuropathology, related to cerebral networks, in KLS during sleep episodes. One patient with KLS and congenital nystagmus was investigated by resting state functional magnetic resonance imaging during both asymptomatic and hypersomnic periods. Fourteen healthy subjects were also investigated as control samples. Functional connectivity was assessed from seed regions of interest in the thalamus and the dorsal pons. Thalamic connectivity was normal in the asymptomatic patient whereas the connectivity between the brain stem, including dorsal pons, and the thalamus was diminished during hypersomnia. These results suggest that the patient’s nystagmus and hypersomnia might have their pathological origin in adjacent dorsal pontine regions. This finding provides additional knowledge of the cerebral networks involved in the neuropathology of this disabling disorder. Furthermore, these findings regarding a rare syndrome have broad implications, and results could be of interest to researchers and clinicians in the whole field of sleep medicine.

  • 19.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Thalamic Activation in the Kleine-Levin Syndrome2014In: Sleep, ISSN 0161-8105, E-ISSN 1550-9109, Vol. 37, no 2, p. 379-386Article in journal (Refereed)
    Abstract [en]

    STUDY OBJECTIVES:

    The objective of this study was to investigate if combined measures of activation in the thalamus and working memory capacity could guide the diagnosis of Kleine-Levin Syndrome (KLS). A second objective was to obtain more insight into the neurobiological causes of KLS.

    DESIGN:

    Matched group and consecutive recruitment.

    SETTING:

    University hospital neurology department and imaging center.

    PATIENTS OR PARTICIPANTS:

    Eighteen patients with KLS diagnosed according to the International Classification of Sleep Disorders and 26 healthy controls were included.

    INTERVENTIONS:

    N/A.

    MEASUREMENTS AND RESULTS:

    Working memory capacity was assessed by the listening span task. A version of this task (reading span) was presented to the participants during functional magnetic resonance imaging (fMRI). Activation in the thalamus was measured in a region of interest analysis. A combination of the working memory capacity and the thalamic activation measures resulted in 80% prediction accuracy, 81% sensitivity, and 78% specificity regarding the ability to separate KLS patients from healthy controls. The controls had an inverse relation between working memory capacity and thalamic activation; higher performing participants had lower thalamic activation (r = -0.41). KLS patients showed the opposite relationship; higher performing participants had a tendency to higher thalamic activation (r = -0.35).

    CONCLUSIONS:

    This study shows that functional neuroimaging of the thalamus combined with neuropsychological assessment of working memory function provides a means to guide diagnosis of Kleine-Levin Syndrome. Results in this study also indicate that imaging of brain function and evaluation of cognitive capacity can give insights into the neurobiological mechanisms of Kleine-Levin Syndrome.

  • 20.
    Engström, Maria
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Craig, A. D. (Bud)
    Atkinson Research Laboratory, Barrow Neurological Institute, Phoenix, AZ.
    Mental energy – an fMRI investigation of the anterior insular and the anterior cingulate network2012Conference paper (Other academic)
  • 21.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Swedish Institute for Disability Research.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Craig, Arthur
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Barrow Neurol Institute, AZ 85013 USA.
    Evidence of conjoint activation of the anterior insular and cingulate cortices during effortful tasks2015In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 8, no 1071Article in journal (Refereed)
    Abstract [en]

    The ability to perform effortful tasks is a topic that has received considerable interest in the research of higher functions of the human brain. Neuroimaging studies show that the anterior insular and the anterior cingulate cortices are involved in a multitude of cognitive tasks that require mental effort. In this study, we investigated brain responses to effort using cognitive tasks with task-difficulty modulations and functional magnetic resonance imaging (fMRI). We hypothesized that effortful performance involves modulation of activation in the anterior insular and the anterior cingulate cortices, and that the modulation correlates with individual performance levels. Healthy participants performed tasks probing verbal working memory capacity using the reading span task, and visual perception speed using the inspection time task. In the fMRI analysis, we focused on identifying effort-related brain activation. The results showed that working memory and inspection time performances were directly related. The bilateral anterior insular and anterior cingulate cortices showed significantly increased activation during each task with common portions that were active across both tasks. We observed increased brain activation in the right anterior insula and the anterior cingulate cortex in participants with low working memory performance. In line with the reported results, we suggest that activation in the anterior insular and cingulate cortices is consistent with the neural efficiency hypothesis (Neubauer).

  • 22.
    Engström, Maria
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Vigren, Patrick
    Neurology INR.
    Landtblom, Anne-Marie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurology. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Subcortical and frontal determinants to working memory deficits in patients with Kleine-Levin syndrome.2007In: 13th Annual Meeting of the Organization for Human Brain Mapping,2007, NeuroImage: Elsevier , 2007, p. S78-Conference paper (Refereed)
  • 23.
    Engström, Maria
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Brain and effort: brain activation and effort-related working memory in healthy participants and patients with working memory deficits2013In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 7, no 140, p. 1-17Article in journal (Refereed)
    Abstract [en]

    Despite the interest in the neuroimaging of working memory, little is still known about the neurobiology of complex working memory in tasks that require simultaneous manipulation and storage of information. In addition to the central executive network, we assumed that the recently described salience network [involving the anterior insular cortex (AIC) and the anterior cingulate cortex (ACC)] might be of particular importance to working memory tasks that require complex, effortful processing.

    Method: Healthy participants (n = 26) and participants suffering from working memory problems related to the Kleine–Levin syndrome (KLS) (a specific form of periodic idiopathic hypersomnia; n = 18) participated in the study. Participants were further divided into a high- and low-capacity group, according to performance on a working memory task (listening span). In a functional magnetic resonance imaging (fMRI) study, participants were administered the reading span complex working memory task tapping cognitive effort.

    Principal findings: The fMRI-derived blood oxygen level dependent (BOLD) signal was modulated by (1) effort in both the central executive and the salience network and (2) capacity in the salience network in that high performers evidenced a weaker BOLD signal than low performers. In the salience network there was a dichotomy between the left and the right hemisphere; the right hemisphere elicited a steeper increase of the BOLD signal as a function of increasing effort. There was also a stronger functional connectivity within the central executive network because of increased task difficulty.

    Conclusion: The ability to allocate cognitive effort in complex working memory is contingent upon focused resources in the executive and in particular the salience network. Individual capacity during the complex working memory task is related to activity in the salience (but not the executive) network so that high-capacity participants evidence a lower signal and possibly hence a larger dynamic response.

  • 24.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Vigren, Patrick
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurology.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Working Memory in 8 Kleine-Levin Syndrome Patients: An fMRI Study2009In: SLEEP, ISSN 0161-8105, Vol. 32, no 5, p. 681-688Article in journal (Refereed)
    Abstract [en]

    Study Objectives: The objectives of this study were to investigate possible neuropathology behind the Kleine-Levin Syndrome (KLS), a severe form of hypersomnia with onset during adolescence.

    Design: Functional magnetic resonance imaging (fMRI) applying a verbal working memory task was used in conjunction with a paper-and-pencil version of the task. Participants: Eight patients with KLS and 12 healthy volunteers participated in the study.

    Results: The results revealed a pattern of increased thalamic activity and reduced frontal activity (involving the anterior cingulate and adjacent prefrontal cortex) while performing a reading span task.

    Discussion: This finding may explain the clinical symptoms observed in KLS, in that the thalamus is known to be involved in the control of sleep. Given the increasing access to fMRI, this investigation may aid clinicians in the diagnosis of patients suffering from severe forms of hypersomnia.

  • 25.
    Gauffin, Helena
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    van Ettinger-Veenstra, Helene
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurobiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ulrici, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    McAllister, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Speech and Language Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of ENT - Head and Neck Surgery UHL.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Swedish Institute for Disability Research. Linköping University, Faculty of Arts and Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Cognitive problems in young adults with epilepsy: Language deficits correlate to brain activation and self-esteemManuscript (preprint) (Other academic)
    Abstract [en]

    People with epilepsy often display cognitive decline. Language function in epilepsy has been most thoroughly studied in temporal lobe epilepsy, but the impact of language deficits in epilepsy is not fully understood. The aim of this study was to evaluate the effect of epilepsy on language function with functional magnetic resonance imaging of brain activation, with behavioral methods and to relate language performance to demographic data, self-esteem and Quality of life. We specifically aimed to investigate if variation in epilepsy origin would relate to differences in language performance and if these differences could be associated with specific language activation patterns in the brain. We recruited people with epilepsy (29 in total), with focal onset seizures in either the left or right hemispheres or with generalized epilepsy; and 27 matching healthy controls. The participants’ language skills were measured with a phonemic word fluency test and a broader test measuring higher language functions. Functional magnetic resonance images of the brain were obtained during a word fluency and a sentence reading paradigm. Questionnaires on self-esteem and quality of life were collected. People with epilepsy of both focal and generalized origin had impaired function in semantic and verbal fluency tasks compared to the controls. The causes of language impairment were multifactorial; the most important determinants were education and onset age of epilepsy. Impaired language function was correlated to low self-esteem for participants with focal onset seizures; however Quality of life did not seem to be affected by language impairment. The functional magnetic resonance imaging investigation demonstrated altered functional activity during language tasks for participants with epilepsy compared to healthy controls. In epilepsy with focal seizures originating in the left hemisphere we found increased bilateral  activation of supporting areas in the anterior mid-cingulate cortex and the left anterior ventral insula, indicating a compensational functional reorganization. In generalized epilepsy, the functional language network showed an imbalance expressed as an inadequate  suppression of activation in the left anterior temporal lobe during semantic processing. Our study shows not only that reduced language functioning is present in people with epilepsy other than in the temporal lobe, but also that frequency of convulsive seizures correlates to language impairment. For patients with focalized seizures, low self esteem correlated also to language impairment. Our results highlight the importance of addressing the negative consequences of language decline in people with epilepsy of both focal and generalized origin.

  • 26.
    Gauffin, Helena
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    van Ettinger-Veenstra, Helene
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ulrici, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    McAllister, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Speech and Language Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Otorhinolaryngology in Linköping.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Impaired language function in generalized epilepsy: Inadequate suppression of the default mode network2013In: Epilepsy & Behavior, ISSN 1525-5050, E-ISSN 1525-5069, Vol. 28, no 1, p. 26-35Article in journal (Refereed)
    Abstract [en]

    We aimed to study the effect of a potential default mode network (DMN) dysfunction on language performance in epilepsy. Language dysfunction in focal epilepsy has previously been connected to brain damage in language-associated cortical areas. In this work, we studied generalized epilepsy (GE) without focal brain damage to see if the language function was impaired. We used functional magnetic resonance imaging (fMRI) to investigate if the DMN was involved. Eleven persons with GE and 28 healthy controls were examined with fMRI during a sentence-reading task. We demonstrated impaired language function, reduced suppression of DMN, and, specifically, an inadequate suppression of activation in the left anterior temporal lobe and the posterior cingulate cortex, as well as an aberrant activation in the right hippocampal formation. Our results highlight the presence of language decline in people with epilepsy of not only focal but also generalized origin.

  • 27.
    Gustafsson, Per
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Child and Adolescent Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Child and Adolescent Psychiatry.
    Birberg Thornberg, Ulrika
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Duchén, Karel
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Landgren, Magnus
    Department of Pediatrics, Mariestad, Sweden .
    Malmberg, Kerstin
    Karolinska Institutet, Stockholm.
    Pelling, Henrik
    Uppsala University.
    Strandvik, Birgitta
    Gothenburg University, Sweden.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    EPA supplementation improves teacher-rated behaviour and oppositional symptoms in children with ADHD2010In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 99, no 10, p. 1540-1549Article in journal (Refereed)
    Abstract [en]

    Aim: Measure efficacy of eicosapentaenoic acid (EPA) in children with attention deficit hyperactivity disorder (ADHD). Methods: Randomized controlled trial (RCT) of 0.5 g EPA or placebo (15 weeks) in 92 children (7-12 years) with ADHD. Efficacy measure was Conners Parent/Teacher Rating Scales (CPRS/CTRS). Fatty acids were analysed in serum phospholipids and red blood cell membranes (RBC) at baseline and endpoint with gas chromatography. Results: EPA improved CTRS inattention/cognitive subscale (p = 0.04), but not Conners total score. In oppositional children (n = 48), CTRS total score improved andgt;= 25% in 48% of the children receiving EPA vs. 9% for placebo [effect size (ES) 0.63, p = 0.01]. In less hyperactive/impulsive children (n = 44), andgt;= 25% improvement was seen in 36% vs. 18% (ES 0.41, n.s.), and with both these types of symptoms 8/13 with EPA vs. 1/9 for placebo improved andgt;= 25% (p = 0.03). Children responding to treatment had lower EPA concentrations (p = 0.02), higher AA/EPA (p = 0.005) and higher AA/DHA ratios (p = 0.03) in serum at baseline. Similarly, AA/EPA (p = 0.01), AA/DHA (p = 0.038) and total omega-6/omega-3 ratios (p = 0.028) were higher in RBC, probably because of higher AA (p = 0.011). Conclusion: Two ADHD subgroups (oppositional and less hyperactive/impulsive children) improved after 15-week EPA treatment. Increasing EPA and decreasing omega-6 fatty acid concentrations in phospholipids were related to clinical improvement.

  • 28.
    Gustafsson, Per
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Child and Adolescent Psychiatry. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Child and Adolescent Psychiatry.
    Duchén, Karel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Pediatrics. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Birberg, Ulrika
    Linköping University, Department of Behavioural Sciences. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences. Linköping University, Faculty of Arts and Sciences.
    Breastfeeding, very long polyunsaturated fatty acids (PUFA) and IQ at 6 1/2 years of age2004In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 93, no 10, p. 1280-1287Article in journal (Refereed)
    Abstract [en]

    Aim: Breastfeeding seems to be favorable for cognitive development. Could levels of polyunsaturated fatty acids (PUFA) explain this? Methods: Pregnant mothers were recruited consecutively at maternity care centres. PUFA were analysed in colostrum and breast milk at 1 and 3 mo. The product-precursor ratios of n-6+n-3 PUFA were examined as measures of activity in respective steps in the fatty acid metabolic chain. Also, the quotient between DHA and AA was analysed. The children were tested with the full WISC-III at 6.5 y. Results: First, the influence of length of breastfeeding was analysed by multiple regression together with relevant cofactors (except for PUFA). In the best models, 46% of the variation in total IQ was explained. Length of breastfeeding contributed significantly to total IQ (beta = 0.228, p = 0.021), verbal IQ (beta = 0.204, p = 0.040) and performance IQ (beta = 0.210, p = 0.056). There were no significant single correlations between PUFA and measures of cognitive development. However, in multiple regression analysis of colostrum, significant beta-coefficients were found for steps 4+5 in the fatty acid metabolic chain (beta = 0.559, p = 0.002). If length of breastfeeding and gestation week were added to steps 4+5, this three-factor model could explain 67% of the variation of total IQ. Introducing length of breastfeeding and gestation week together with the quotient DHA/AA (beta = 0.510, p < 0.001) yielded a three-factor model, which explained 76% of the variation in total IQ. Conclusion: Our findings could be interpreted as supporting the importance of high levels of PUFA for cognitive development. However, the sample is small and the results must be interpreted with caution.

  • 29.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Cognitive and neuropsychological aspects of age-associated memory decline1992Other (Other (popular science, discussion, etc.))
  • 30.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Neuropsykologi och kognitiv neurovetenskap: ny kunskap för militärt och civilt försvar (Neuropsychology and cognitive neuroscience2001Report (Other academic)
  • 31.
    Karlsson, Thomas
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Adolfsson, R.
    Borjesson, A.
    Nilsson, L.G.
    Primed word-fragment completion and successive memory test performance in normal aging2003In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 44, no 4, p. 355-361Article in journal (Refereed)
    Abstract [en]

    Young and old subjects were investigated to examine whether: the effects of priming are influenced by aging there is independence between primed word-fragment completion and recognition performances, and the dependence between different tests is influenced by aging. A successive test paradigm was employed involving repeated assessment of to-be-remembered words by means of recognition and primed word-fragment completion. The results show that implicit memory declines with increasing age, and that correlations between different memory tests decrease with age. The outcome suggests that age-related memory decline involves several forms of memory, including primed word-fragment completion, and is reflected in correlations between measures of implicit and explicit memory.

  • 32.
    Karlsson, Thomas
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Bäckman, L.
    Herlitz, A.
    Nilsson, L-G.
    Winblad, B.
    Österlind, P-O.
    Memory improvement at different stages of Alzheimer's disease1989In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 27, p. 737-742Article in journal (Refereed)
  • 33.
    Karlsson, Thomas
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Börjesson, A.
    Adolfsson, R.
    Nilsson, L-G.
    Successive memory test performance and priming in Alzheimer's disease: Evidence from the word-fragment completion task2002In: Cortex, ISSN 0010-9452, E-ISSN 1973-8102, Vol. 38, no 3, p. 341-355Article in journal (Refereed)
    Abstract [en]

    This study assessed the performance of patients with Alzheimer's disease and healthy controls in a successive memory test paradigm. Subjects studied lists of words. Following study, tests of recognition (an explicit memory task) and primed word fragment completion (an implicit memory task) were administered. Since the same words were used in the two tasks, we were able to calculate the degree of dependence between recognition performance and primed word fragment completion. AD patients evidenced impaired recognition memory. In contrast, priming was intact. The pattern of correlation between the two tasks was similar in healthy controls and in AD. Independence between recognition and fragment completion was obtained when recognition preceded the fragment completion task, but not when fragment completion preceded recognition.

  • 34.
    Karlsson, Thomas
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Classon, Elisabet
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, The Swedish Institute for Disability Research.
    Rönnberg, Jerker
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Den hjärnvänliga arbetsplatsen: kognition, kognitiva funktionsnedsättningar och arbetsmiljö2014Report (Other academic)
    Abstract [sv]

    Dagens arbetsliv ställer allt större krav på kognitiva förmågor. Vi arbetar alltmer med information inte bara i traditionellt intellektuella yrken, utan även inom industri, hantverk och sjukvård. Informationsteknologi i form av datorer, avancerad teknisk utrustning och andra komplexa system blir allt viktigare att kunna hantera. Detta ställer nya krav på arbetsmiljöarbetet, något som gäller för alla arbetstagare, men särskilt för de av oss som har en kognitiv funktionsnedsättning.

    I denna rapport sammanfattar vi arbetsmiljörelaterade hinder förknippade med nedsatt funktion inom nio kognitiva områden: språk, exekutiva funktioner, minnesfunktioner, visuospatiala funktioner, snabbhet, uppmärksamhet, emotion/social kognition, mental trötthet samt global kognitiv förmåga/intelligens. Vi uppmärksammar även mental trötthet (”fatigue”) som ett viktigt problemområde i  sammanhanget.

    Den första delen av rapporten ger en bakgrund till området. Avsnittet ger en kort översikt över neuropsykologi och kognitiv neurovetenskap.

    Den andra delen sammanfattar kunskap om omfattningen av problemet: hur vanliga är kognitiva funktionsnedsättningar i arbetslivet? En stor del av de människor som är i yrkesverksam ålder antingen har, eller kommer någon gång under yrkeslivet att drabbas av kognitiva funktionsproblem. Vi uppskattar att detta berör en femtedel till en tredjedel av de yrkesverksamma. Eftersom kognitiv funktionsnivå långt ifrån enbart beror på individens begränsningar till följd av sjukdom eller annan funktionsnedsättning, utan även på miljön och dess krav på individen, är problemen och lösningar på dessa både giltiga och viktiga för alla.

    Rapportens andra del visar att kognitiv nedsättning inte begränsas till ett enstaka funktionellt område, exempelvis minnesbesvär, utan kan innefatta flera av de funktionella områden som berörs. Det finns alltså ingen enkel koppling mellan en sjukdom och vilka kognitiva funktionsproblem den medför för den enskilde arbetstagaren. Problemen måste ses i ljuset av både de erfarenheter och begränsningar den enskilde personen har och den aktuella arbetsuppgiften.

    Rapportens tredje del diskuterar mer ingående arbetsmiljörelaterade konsekvenser av kognitiva funktionsnedsättningar. Den börjar med att sammanfatta en modell för att analysera funktionsnedsättningar som en produkt av fyra samverkande faktorer: individen (till exempel kognitiva funktionsbegränsningar efter en sjukdom), individens förhållningssätt (till exempel motivation), arbetsuppgiften och miljön. En kognitiv funktionsproblematik finns aldrig enbart i en av dessa faktorer utan i skärningspunkten mellan dessa faktorer. Av detta skäl är kunskap om arbetsmiljömässiga aspekter av kognitiva funktionsnedsättningar giltig för alla. Även de som inte har nedsatt kognitiv funktion hamnar i situationer där faktorer kopplade till miljön eller arbetsuppgiften (eller vår inställning till uppgiften) resulterar i att kognitiva förmågor belastas!

    Vidare identifierar och sammanfattar rapportens tredje del praktiska lösningar som stödjer arbetsförmåga vid nedsättning av funktioner inom de nio områden som rapporten omfattar: språk, exekutiva funktioner, minnesfunktioner, visuospatiala funktioner, snabbhet, uppmärksamhet, emotion/social kognition, mental trötthet samt global kognitiv förmåga/intelligens. Särskilt betonas att det idag finns många tillgängliga men sannolikt mindre ofta utnyttjade åtgärder som kan utnyttjas för att mildra eller eliminera arbetsmiljöproblem relaterade till kognitiva funktionsnedsättningar. Rapporten redovisar sju sådana övergripande åtgärder. Därtill diskuteras kognitiva funktionsnedsättningar i samband med arbetstagare som är över 65 år och arbetsgivarens roll. Avslutningsvis identifieras kunskapsbehov för fortsatt arbete inom området.

  • 35.
    Karlsson, Thomas
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Johansson, I.
    Adolfsson, R.
    Nilsson, L-G.
    Dubuc, S.
    A demonstration of a remarkable memory capacity in Alzheimer's Disease2003In: Dementia and Geriatric Cognitive Disorders, ISSN 1420-8008, E-ISSN 1421-9824, Vol. 15Article in journal (Refereed)
  • 36.
    Karlsson, Thomas
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Johansson, I.
    Department of Psychology, Umeå University, Umeå, Sweden.
    Adolfsson, R.
    Department of Psychiatry, Umeå University, Umeå, Sweden.
    Nilsson, L.-G.
    Department of Psychology, Stockholm University, Stockholm, Sweden.
    Dubuc, S.
    Recognition memory in Alzheimer's disease: A demonstration of a remarkable memory capacity in Alzheimer's disease2003In: Dementia and Geriatric Cognitive Disorders, ISSN 1420-8008, E-ISSN 1421-9824, Vol. 15, no 1Article in journal (Refereed)
    Abstract [en]

    A compelling feature of human memory is its striking capacity. Under certain circumstances, subjects can remember large amounts of information even with brief exposure at study. This investigation shows that this ability is preserved even in severely impaired Alzheimer's disease patients, and this holds implications for the clinical management of amnesic patients. To this date, demonstrations of preserved learning and memory capacity in Alzheimer's disease and amnesia have been confined to implicit memory tasks. Since the present results were obtained in an explicit memory task, the finding also holds implications for the understanding of amnesia. Copyright © 2003 S. Karger AG, Basel.

  • 37.
    Karlsson, Thomas
    et al.
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Mårdh, Selina
    Linköping University, Department of Behavioural Sciences and Learning, Psychology. Linköping University, Faculty of Arts and Sciences.
    Marcusson, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Geriatric. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine.
    Emotion and recollective experience in Alzheimer’s diseaseManuscript (preprint) (Other academic)
    Abstract [en]

    Emotional changes are common in Alzheimer’s disease (AD). In addition, damage to brain regions involved in emotion is abundant in AD. Although these finding imply that emotion memory is severely compromised in AD, absolute or relative sparing of emotional memory has occasionally been reported. Hence, we wanted to clarify how well AD patients can remember emotion words. Eighteen AD patients and fifteen healthy older persons participated in the experiment. Participants studied neutral, positive, and negative words. Implicit and explicit memory was assessed in two tasks: a word-fragment completion task and a recognition task, respectively. In the latter task, participants were asked to provide recollective judgments when they indicated that they recognized a word from previous study. Results indicated that AD patients responded to valence, and in particular negative valence, similar to controls, that AD patients evidenced severe deficits as to recollective experience, and that implicit memory remained intact in AD.

  • 38. Kristensen, B.
    et al.
    Malm, J.
    Fagerlund, M.
    Hiettala, S-O.
    Johansson, B.
    Ekstedt, J.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Regional cerebral blood-flow in the adult hydrocephalus syndrom1996In: Journal of Neurology, Neurosurgery and Psychiatry, ISSN 0022-3050, E-ISSN 1468-330X, Vol. 60, p. 282-288Article in journal (Refereed)
  • 39.
    Levin, Britta
    et al.
    FOI.
    Andersson, Jan
    FOI.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Memory performance during G exposure as assessed by a word recognition task2007In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 78, no 6, p. 587-592Article in journal (Refereed)
    Abstract [en]

    Background: Pilots of modern fighter aircraft are exposed to substantial physiological and mental stressors. The objective of this study was to investigate how memory performance, in terms of encoding and/or retrieval processes, was affected by sustained +Gz exposure. Method: There were 18 healthy men ranging from experienced fighter pilots to novice riders who participated. A word continuous recognition task (CRT) was employed as a memory test. The task consisted of three consecutive phases: 1) encoding of familiar words at 1 G, 2) encoding and retrieval of words at 70% of the subject's relaxed G-tolerance level, equivalent to +3.7 ± 0.54 Gz, and 3) encoding and retrieval of words at 1 G. In addition, each subject performed the CRT in a 1-G-only control condition. Physiological and psycho-physiological measures included continuous monitoring of ECG, arterial oxygen saturation, arterial BP at head level, and response time. Results: Data analysis showed that the capability to recognize words encoded at 1 G did not differ between conditions, indicating that the retrieval process was insensitive to increased Gz load. However, the ability to recognize words previously encoded during G exposure was reduced by approximately 10% as compared with control. Since the analysis revealed that the words were perceived, this result suggests that the encoding process was impaired in hypergravity. Conclusion: The results indicate that memory encoding, but not retrieval, was affected negatively when exposed to substantial and sustained +Gz loads. Copyright © by Aerospace Medical Association.

  • 40. Lundqvist, A-K.
    et al.
    Thors, A.
    Bäckman, L.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability. Linköping University, Faculty of Arts and Sciences.
    Nilsson, L-G.
    Maintenance of acquired memory skills in older adults1988In: Cognitive Psychotherapy: An Update / [ed] Carlo Perris, Martin Eisemann, Umeå: Dopuu Press , 1988Chapter in book (Other academic)
  • 41. Malm, J.
    et al.
    Kristensen, B.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Carlberg, B.
    Fagerlund, M.
    Olsson, T.
    Cognitive impairment in young adults with infratentorial infarcts1998In: Neurology, ISSN 0028-3878, E-ISSN 1526-632X, Vol. 51, p. 433-440Article in journal (Refereed)
  • 42. Malm, J.
    et al.
    Kristensen, B.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Fagerlund, M.
    Elfverrson, J.
    Ekstedt, J.
    The predictive value of cerebrospinal fluid dynamic tests in patients with the idiopathic adult hydrocephalus syndrome1995In: Archives of Neurology, ISSN 0003-9942, E-ISSN 1538-3687, Vol. 52, p. 783-789Article in journal (Refereed)
  • 43.
    Neselius, Sanna
    et al.
    Sahlgrenska University Hospital, Gothenburg, Sweden.
    Brisby, Helena
    Sahlgrenska University Hospital, Gothenburg, Sweden.
    Marcusson, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine in Linköping.
    Zetterberg, Henrik
    Sahlgrenska University Hospital, Mölndal, Sweden.
    Blennow, Kaj
    Sahlgrenska University Hospital, Mölndal, Sweden.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Neurological Assessment and Its Relationship to CSF Biomarkers in Amateur Boxers2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 6, p. e0099870-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Mild traumatic brain injury (TBI) or concussion is common in many sports. Today, neuropsychological evaluation is recommended in the monitoring of a concussion and in return-to-play considerations. To investigate the sensitivity of neuropsychological assessment, we tested amateur boxers post bout and compared with controls. Further the relationship between neuropsychological test results and brain injury biomarkers in the cerebrospinal fluid (CSF) were investigated.

    METHOD:

    Thirty amateur boxers on high elite level with a minimum of 45 bouts and 25 non-boxing matched controls were included. Memory tests (Rey Osterrieth Complex Figure, Listening Span, Digit Span, Controlled Word Association Test, and computerized testing of episodic memory), tests of processing speed and executive functions (Trail Making, Reaction Time, and Finger Tapping) were performed and related to previously published CSF biomarker results for the axonal injury marker neurofilament light (NFL).

    RESULTS:

    The neurological assessment showed no significant differences between boxers and controls, although elevated CSF NFL, as a sign of axonal injury, was detected in about 80% of the boxers 1-6 days post bout. The investigation of the relationship between neuropsychological evaluation and CSF NFL concentrations revealed that boxers with persisting NFL concentration elevation after at least 14 days resting time post bout, had a significantly poorer performance on Trail Making A (p = 0.041) and Simple Reaction Time (p = 0.042) compared to other boxers.

    CONCLUSION:

    This is the first study showing traumatic axonal brain injury can be present without measureable cognitive impairment. The repetitive, subconcussive head trauma in amateur boxing causes axonal injury that can be detected with analysis of CSF NFL, but is not sufficient to produce impairment in memory tests, tests of processing speed, or executive functions. The association of prolonged CSF NFL increase in boxers with impairment of processing speed is an interesting observation, which needs to be verified in larger studies.

  • 44. Nilsson, L-G.
    et al.
    Bäckman, L.
    Herlitz, A.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Österlind, P-O.
    Winblad, B.
    Patterns of memory performance in young-old and old-old adults: A selective review1987In: Comprehensive gerontology. Section B, Behavioural, social and applied sciences, ISSN 0902-008X, Vol. 1, p. 49-53Article in journal (Refereed)
  • 45. Nilsson, L-G.
    et al.
    Bäckman, L.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    Priming and cued recall in elderly, alcohol intoxicated and sleep deprived subjects: a case of functionally similar memory deficits1989In: Psychological Medicine, ISSN 0033-2917, E-ISSN 1469-8978, Vol. 19, p. 423-433Article in journal (Refereed)
  • 46. Rasmussen, A.G.
    et al.
    Adolfsson, R.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability.
    New method specific for acetylcholinesterase in cerebrospinal fluid: application to Alzheimer's disease1988In: The Lancet, ISSN 0140-6736, E-ISSN 1474-547X, Vol. 2, p. 571-572Article in journal (Refereed)
  • 47.
    Rudner, Mary
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Gunnarsson, Johan
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Rönnberg, Jerker
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Levels of processing and language modality specificity in working memory2013In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 51, no 4, p. 656-666Article in journal (Refereed)
    Abstract [en]

    Neural networks underpinning working memory demonstrate sign language specific components possibly related to differences in temporary storage mechanisms. A processing approach to memory systems suggests that the organisation of memory storage is related to type of memory processing as well. In the present study, we investigated for the first time semantic, phonological and orthographic processing in working memory for sign- and speech-based language. During fMRI we administered a picture-based 2-back working memory task with Semantic, Phonological, Orthographic and Baseline conditions to 11 deaf signers and 20 hearing non-signers. Behavioural data showed poorer and slower performance for both groups in Phonological and Orthographic conditions than in the Semantic condition, in line with depth-of-processing theory. An exclusive masking procedure revealed distinct sign-specific neural networks supporting working memory components at all three levels of processing. The overall pattern of sign-specific activations may reflect a relative intermodality difference in the relationship between phonology and semantics influencing working memory storage and processing.

  • 48.
    Rudner, Mary
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Rönnberg, Jerker
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Levels of processing in working memory for signed and speech-based language2011Conference paper (Other academic)
  • 49.
    Rudner, Mary
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Rönnberg, Jerker
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Semantic, phonoligical and orthographic processing in working memory for signed and speech-based language2011Conference paper (Other academic)
  • 50.
    Rudner, Mary
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Rönnberg, Jerker
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Semantic, phonological and orthographic processing in working memory for signed and speech-based language2011Conference paper (Other academic)
    Abstract [en]

    Working memory processing and maintenance components are supported by a fronto-parietal network that is largely similar, yet subtly different, for signed and speech-based languages. In the present study, we investigated for the first time modality-specific differences in the neural correlates of three different varieties of working memory processing (semantic, phonological and orthographic) in 11 deaf early users of Swedish Sign Language and 19 hearing native Swedish speakers using a picture-based 2-back fMRI paradigm. Contrasts between each of the processing levels and a 2-back, picture-based but non-linguistic baseline condition activated distinct networks between groups. In particular, the two groups activated only partially overlapping networks in regions previously associated with the three different kinds of processing. This suggests that the mechanisms supporting different varieties of working memory processing differ at least partially between modalities.

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