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  • 1.
    Bondesson, Lennart
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Traat, Imbi
    Institute of Mathematical Statistics , University of Tartu , Estonia.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Pareto sampling versus Sampford and Conditional Poisson sampling2006In: Scandinavian Journal of Statistics, ISSN 0303-6898, E-ISSN 1467-9469, Vol. 33, no 4, p. 699-720Article in journal (Refereed)
    Abstract [en]

    Pareto sampling was introduced by Rosén in the late 1990s. It is a simple method to get a fixed size πps sample though with inclusion probabilities only approximately as desired. Sampford sampling, introduced by Sampford in 1967, gives the desired inclusion probabilities but it may take time to generate a sample. Using probability functions and Laplace approximations, we show that from a probabilistic point of view these two designs are very close to each other and asymptotically identical. A Sampford sample can rapidly be generated in all situations by letting a Pareto sample pass an acceptance–rejection filter. A new very efficient method to generate conditional Poisson (CP) samples appears as a byproduct. Further, it is shown how the inclusion probabilities of all orders for the Pareto design can be calculated from those of the CP design. A new explicit very accurate approximation of the second-order inclusion probabilities, valid for several designs, is presented and applied to get single sum type variance estimates of the Horvitz–Thompson estimator.

  • 2.
    Boraxbekk, Carl-Johan
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nilsson, Lars-Göran
    Aging Research Center, Karolinska Institutet.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Free Recall Episodic Memory Performance Predicts Dementia 10 Years Prior to Clinical Diagnosis: Findings from the Betula Longitudinal Study2015In: Dementia and geriatric cognitive disorders extra, E-ISSN 1664-5464, Vol. 5, no 2, p. 191-202Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Early dementia diagnosis is a considerable challenge. The present study examined the predictive value of cognitive performance for a future clinical diagnosis of late-onset Alzheimer's disease or vascular dementia in a random population sample. Methods: Cognitive performance was retrospectively compared between three groups of participants from the Betula longitudinal cohort. Group 1 developed dementia 11-22 years after baseline testing (n = 111) and group 2 after 1-10 years (n = 280); group 3 showed no deterioration towards dementia during the study period (n = 2,855). Multinomial logistic regression analysis was used to investigate the predictive value of tests reflecting episodic memory performance, semantic memory performance, visuospatial ability, and prospective memory performance. Results: Age-and education-corrected performance on two free recall episodic memory tests significantly predicted dementia 10 years prior to clinical diagnosis. Free recall performance also predicted dementia 11-22 years prior to diagnosis when controlling for education, but not when age was added to the model. Conclusion: The present results support the suggestion that two free recall-based tests of episodic memory function may be useful for detecting individuals at risk of developing dementia 10 years prior to clinical diagnosis.

  • 3. Davies, G.
    et al.
    Armstrong, N.
    Bis, J. C.
    Bressler, J.
    Chouraki, V.
    Giddaluru, S.
    Hofer, E.
    Ibrahim-Verbaas, C. A.
    Kirin, M.
    Lahti, J.
    van der Lee, S. J.
    Le Hellard, S.
    Liu, T.
    Marioni, R. E.
    Oldmeadow, C.
    Postmus, I.
    Smith, A. V.
    Smith, J. A.
    Thalamuthu, A.
    Thomson, R.
    Vitart, V.
    Wang, J.
    Yu, L.
    Zgaga, L.
    Zhao, W.
    Boxall, R.
    Harris, S. E.
    Hill, W. D.
    Liewald, D. C.
    Luciano, M.
    Adams, H.
    Ames, D.
    Amin, N.
    Amouyel, P.
    Assareh, A. A.
    Au, R.
    Becker, J. T.
    Beiser, A.
    Berr, C.
    Bertram, L.
    Boerwinkle, E.
    Buckley, B. M.
    Campbell, H.
    Corley, J.
    De Jager, P. L.
    Dufouil, C.
    Eriksson, J. G.
    Espeseth, T.
    Faul, J. D.
    Ford, I.
    Gottesman, R. F.
    Griswold, M. E.
    Gudnason, V.
    Harris, T. B.
    Heiss, G.
    Hofman, A.
    Holliday, E. G.
    Huffman, J.
    Kardia, S. L. R.
    Kochan, N.
    Knopman, D. S.
    Kwok, J. B.
    Lambert, J-C
    Lee, T.
    Li, G.
    Li, S-C
    Loitfelder, M.
    Lopez, O. L.
    Lundervold, A. J.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Mather, K. A.
    Mirza, S. S.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Oostra, B. A.
    Palotie, A.
    Papenberg, G.
    Pattie, A.
    Petrovic, K.
    Polasek, O.
    Psaty, B. M.
    Redmond, P.
    Reppermund, S.
    Rotter, J. I.
    Schmidt, H.
    Schuur, M.
    Schofield, P. W.
    Scott, R. J.
    Steen, V. M.
    Stott, D. J.
    Van Swieten, J. C.
    Taylor, K. D.
    Trollor, J.
    Trompet, S.
    Uitterlinden, A. G.
    Weinstein, G.
    Widen, E.
    Windham, B. G.
    Jukema, J. W.
    Wright, A. F.
    Wright, M. J.
    Yang, Q.
    Amieva, H.
    Attia, J. R.
    Bennett, D. A.
    Brodaty, H.
    de Craen, A. J. M.
    Hayward, C.
    Ikram, M. A.
    Lindenberger, U.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). ARC, Karolinska Institutet, Stockholm.
    Porteous, D. J.
    Raikkonen, K.
    Reinvang, I.
    Rudan, I.
    Sachdev, P. S.
    Schmidt, R.
    Schofield, P. R.
    Srikanth, V.
    Starr, J. M.
    Turner, S. T.
    Weir, D. R.
    Wilson, J. F.
    Van Duijn, C.
    Launer, L.
    Fitzpatrick, A. L.
    Seshadri, S.
    Jr, T. H. Mosley
    Deary, I. J.
    Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53 949)2015In: Molecular Psychiatry, ISSN 1359-4184, E-ISSN 1476-5578, Vol. 20, no 2, p. 183-192Article in journal (Refereed)
    Abstract [en]

    General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health-and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N = 53 949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P = 3.93 x 10(-9), MIR2113; rs17522122, P = 2.55 x 10(-8), AKAP6; rs10119, P = 5.67 x 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P = 1x10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N = 6617) and the Health and Retirement Study (N = 5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e. = 5%) and 28% (s.e. = 7%), respectively. Using polygenic prediction analysis, similar to 1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N = 5487; P = 1.5 x 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

  • 4.
    Ekman, Urban
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Domellöf, Magdalena
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Elgh, Eva
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Longitudinal changes in task-evoked brain responses in Parkinson's disease patients with and without mild cognitive impairment2014In: Frontiers in Neuroscience, ISSN 1662-4548, E-ISSN 1662-453X, Vol. 8, article id 207Article in journal (Refereed)
    Abstract [en]

    Cognitive deficits are common in Parkinson's disease. Previous cross-sectional research has demonstrated a link between cognitive impairments and fronto-striatal dopaminergic dysmodulation. However, longitudinal studies that link disease progression with altered task-evoked brain activity are lacking. Therefore, our objective was to longitudinally evaluate working-memory related brain activity changes in Parkinson's disease patients with and without mild cognitive impairment (MCI). Patients were recruited within a longitudinal cohort study of incident patients with idiopathic parkinsonism. We longitudinally (at baseline examination and at 12-months follow-up) compared 28 patients with Parkinson's disease without MCI with 11 patients with Parkinson's disease and MCI. Functional MRI blood oxygen level dependent signal was measured during a verbal two-back working-memory task. Patients with MCI under-recruited bilateral medial prefrontal cortex at both time-points (main effect of group: p < 0.001, uncorrected). Critically, a significant group-by-time interaction effect (p < 0.001, uncorrected) was found in the right fusiform gyrus, indicating that working-memory related activity decreased for patients with Parkinson's disease and MCI between baseline and follow-up, while patients without MCI were stable across time-points. The functional connectivity between right fusiform gyrus and bilateral caudate nucleus was stronger for patients without MCI relative to patients with MCI. Our findings support the view that deficits in working-memory updating are related to persistent fronto-striatal under-recruitments in patients with early phase Parkinson's disease and MCI. The longitudinal evolution of MCI in Parkinson's disease translates into additional task-evoked posterior cortical changes.

  • 5.
    Eriksson, Staffan
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Gustafson, Yngve
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Comparison of three statistical methods for analysis of fall predictors in people with dementia: negative binomial regression (NBR), regression tree (RT), and partial least squares regression (PLSR)2009In: Archives of gerontology and geriatrics (Print), ISSN 0167-4943, E-ISSN 1872-6976, Vol. 49, no 3, p. 383-389Article in journal (Refereed)
    Abstract [en]

    Searching for background factors associated with falls in people with dementia is difficult because the population is heterogeneous. The aim of this study was to compare the efficacies of three statistical methods for analysis of fall predictors in people with dementia. NBR, RT and PLSR analyses were compared. Data used for the comparison were from a prospective cohort study of 192 patients at a psychogeriatric ward, specializing in patients with cognitive impairment and related behavioral and psychological symptoms. Seventy-eight of these patients fell a total of 238 times. PLSR and RT analyses are directed at finding patterns among predictor variables related to outcome, whereas an NBR model is directed at finding predictor variables that, independent of other variables, are related to the outcome. The NBR analysis explained an additional 10–15% variation compared with the PLSR and RT analyses. The results of PLSR and RT show a similar plausible pattern of predictor variables. However, none of these techniques appears to be sufficient in itself. In order to gain patterns of explanatory variables, RT would be a good complement to NBR for analysis of fall predictors.

  • 6. Giddaluru, Sudheer
    et al.
    Espeseth, Thomas
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, 11330 Stockholm, Sweden.
    Westlye, Lars T
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Christoforou, Andrea
    Cichon, Sven
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Steen, Vidar M
    Reinvang, Ivar
    Nilsson, Lars Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). ARC, Karolinska Institutet, Stockholm, Sweden.
    Le Hellard, Stéphanie
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Genetics of structural connectivity and information processing in the brain2016In: Brain Structure and Function, ISSN 1863-2653, E-ISSN 1863-2661, Vol. 221, no 9, p. 4643-4661Article in journal (Refereed)
    Abstract [en]

    Understanding the genetic factors underlying brain structural connectivity is a major challenge in imaging genetics. Here, we present results from genome-wide association studies (GWASs) of whole-brain white matter (WM) fractional anisotropy (FA), an index of microstructural coherence measured using diffusion tensor imaging. Data from independent GWASs of 355 Swedish and 250 Norwegian healthy adults were integrated by meta-analysis to enhance power. Complementary GWASs on behavioral data reflecting processing speed, which is related to microstructural properties of WM pathways, were performed and integrated with WM FA results via multimodal analysis to identify shared genetic associations. One locus on chromosome 17 (rs145994492) showed genome-wide significant association with WM FA (meta P value = 1.87 × 10(-08)). Suggestive associations (Meta P value <1 × 10(-06)) were observed for 12 loci, including one containing ZFPM2 (lowest meta P value = 7.44 × 10(-08)). This locus was also implicated in multimodal analysis of WM FA and processing speed (lowest Fisher P value = 8.56 × 10(-07)). ZFPM2 is relevant in specification of corticothalamic neurons during brain development. Analysis of SNPs associated with processing speed revealed association with a locus that included SSPO (lowest meta P value = 4.37 × 10(-08)), which has been linked to commissural axon growth. An intergenic SNP (rs183854424) 14 kb downstream of CSMD1, which is implicated in schizophrenia, showed suggestive evidence of association in the WM FA meta-analysis (meta P value = 1.43 × 10(-07)) and the multimodal analysis (Fisher P value = 1 × 10(-07)). These findings provide novel data on the genetics of WM pathways and processing speed, and highlight a role of ZFPM2 and CSMD1 in information processing in the brain.

  • 7.
    Gorbach, Tetiana
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Orädd, Greger
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Josefsson, Maria
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden.
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Longitudinal association between hippocampus atrophy and episodic-memory decline2017In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 51, p. 167-176Article in journal (Refereed)
    Abstract [en]

    There is marked variability in both onset and rate of episodic-memory decline in aging. Structural magnetic resonance imaging studies have revealed that the extent of age-related brain changes varies markedly across individuals. Past studies of whether regional atrophy accounts for episodic-memory decline in aging have yielded inconclusive findings. Here we related 15-year changes in episodic memory to 4-year changes in cortical and subcortical gray matter volume and in white-matter connectivity and lesions. In addition, changes in word fluency, fluid IQ (Block Design), and processing speed were estimated and related to structural brain changes. Significant negative change over time was observed for all cognitive and brain measures. A robust brain-cognition change-change association was observed for episodic-memory decline and atrophy in the hippocampus. This association was significant for older (65-80 years) but not middle-aged (55-60 years) participants and not sensitive to the assumption of ignorable attrition. Thus, these longitudinal findings highlight medial-temporal lobe system integrity as particularly crucial for maintaining episodic-memory functioning in older age. 

  • 8.
    Harrefors, Christina
    et al.
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Sävenstedt, Stefan
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Bengt
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Axelsson, Karin
    Institutionen för Hälsovetenskap, Luleå Tekniska Universitet.
    Professional caregivers' perceptions on how persons with mild dementia might experience the usage of a digital photo diary2012In: Open Nursing Journal, ISSN 1874-4346, E-ISSN 1874-4346, Vol. 6, p. 20-29Article in journal (Refereed)
    Abstract [en]

    Cognitive impairments influence the possibility of persons with dementia to remember daily events and maintain a sense of self. In order to address these problems a digital photo diary was developed to capture information about events in daily life. The device consisted of a wearable digital camera, smart phone with Global Positioning System (GPS) and a home memory station with computer for uploading the photographs and touch screen. The aim of this study was to describe professional caregiver's perceptions on how persons with mild dementia might experience the usage of this digital photo diary from both a situation when wearing the camera and a situation when viewing the uploaded photos, through a questionnaire with 408 respondents. In order to catch the professional caregivers' perceptions a questionnaire with the semantic differential technique was used and the main question was "How do you think Hilda (the fictive person in the questionnaire) feels when she is using the digital photo diary?". The factor analysis revealed three factors; Sense of autonomy, Sense of self-esteem and Sense of trust. An interesting conclusion that can be drawn is that professional caregivers had an overall positive view of the usage of digital photo diary as supporting autonomy for persons with mild dementia. The meaningfulness of each situation when wearing the camera and viewing the uploaded pictures to be used in two different situations and a part of an integrated assistive device has to be considered separately. Individual needs and desires of the person who is living with dementia and the context of each individual has to be reflected on and taken into account before implementing assistive digital devices as a tool in care.

  • 9.
    Jonasson, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Kramer, Arthur
    Departments of Psychology and Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Riklund, Katrine
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital, Hvidovre, Denmark.
    Aerobic Exercise Intervention, CognitivePerformance, and Brain Structure: results from the Physical Influences on Brain in Aging (PHIBRA) Study2017In: Frontiers in Aging Neuroscience, ISSN 1663-4365, E-ISSN 1663-4365, Vol. 8, p. 1-15, article id 336Article in journal (Refereed)
    Abstract [en]

    Studies have shown that aerobic exercise has the potential to improve cognition and reduce brain atrophy in older adults. However, the literature is equivocal with regards to the specificity or generality of these effects. To this end, we report results on cognitive function and brain structure from a 6-month training intervention with 60 sedentary adults (64–78 years) randomized to either aerobic training or stretching and toning control training. Cognitive functions were assessed with a neuropsychological test battery in which cognitive constructs were measured using several different tests. Freesurfer was used to estimate cortical thickness in frontal regions and hippocampus volume. Results showed that aerobic exercisers, compared to controls, exhibited a broad, rather than specific, improvement in cognition as indexed by a higher “Cognitive score,” a composite including episodic memory, processing speed, updating, and executive function tasks (p = 0.01). There were no group differences in cortical thickness, but additional analyses revealed that aerobic fitness at baseline was specifically related to larger thickness in dorsolateral prefrontal cortex (dlPFC), and hippocampus volume was positively associated with increased aerobic fitness over time. Moreover, “Cognitive score” was related to dlPFC thickness at baseline, but changes in “Cognitive score” and dlPFC thickness were associated over time in the aerobic group only. However, aerobic fitness did not predict dlPFC change, despite the improvement in “Cognitive score” in aerobic exercisers. Our interpretation of these observations is that potential exercise-induced changes in thickness are slow, and may be undetectable within 6-months, in contrast to change in hippocampus volume which in fact was predicted by the change in aerobic fitness. To conclude, our results add to a growing literature suggesting that aerobic exercise has a broad influence on cognitive functioning, which may aid in explaining why studies focusing on a narrower range of functions have sometimes reported mixed results.

  • 10.
    Josefsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Imputation of missing longitudinal fMRI dataManuscript (preprint) (Other academic)
  • 11.
    Kauppi, Karolina
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nilsson, Lars-Göran
    Stockholm University.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Eriksson, Elias
    Gothenburg University.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Decreased medial temporal lobe activation in BDNF 66Met allele carriers during memory encoding2013In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 51, no 12, p. 2462-2468Article in journal (Refereed)
    Abstract [en]

    The Met allele of the Brain-derived neurotrophic factor (BDNF) Val(66)Met polymorphism has been associated with impaired activity-dependent secretion of BDNF protein and decreased memory performance. Results from imaging studies relating Val(66)Met to brain activation during memory processing have been inconsistent, with reports of both increased and decreased activation in the Medial Temporal Lobe (MTL) in Met carriers relative to Val homozygotes. Here, we extensively studied BDNF Val(66)Met in relation to brain activation and white matter integrity as well as memory performance in a large imaging (n=194) and behavioral (n=2229) sample, respectively. Functional magnetic resonance imaging (fMRI) was used to investigate MTL activation in healthy participants in the age of 55-75 years during a face-name episodic encoding and retrieval task. White matter integrity was measured using diffusion tensor imaging.

    BDNF Met allele carriers had significantly decreased activation in the MTL during encoding processes, but not during retrieval processes. In contrast to previous proposals, the effect was not modulated by age and the polymorphism was not related to white matter integrity. Met carriers had lower memory performance than Val homozygotes, but differences were subtle and not significant. In conclusion, the BDNF Met allele has a negative influence on MTL functioning, preferentially during encoding processes, which might translate into impaired episodic memory function.

  • 12.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    A note on choosing sampling probabilities for conditional Poisson samplingManuscript (Other academic)
    Abstract [en]

    For conditional Poisson sampling the sampling probabilities and the achieved inclusion probabilities are not identical, which is a problem. We present a general method for choosing the sampling probabilities, which uses only the desired inclusion probabilities and transformations of them. We compare the performance of this new method to other reasonable choices of sampling probabilities.

  • 13.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Balanced unequal probability sampling with maximum entropyManuscript (Other academic)
    Abstract [en]

    This paper investigates how to perform balanced unequal probability sampling with maximum entropy. Focus is on balancing conditions having the form of known marginal sums in a cross-stratification table. Since only marginal sums are fixed, the sample sizes for one or more cells in the table are random. The probability distribution for those sample sizes can be expressed explicitly but there are computational difficulties except for very small cases. Markov Chain Monte Carlo methods are proposed for obtaining good distribution approximations, as well as sample selection. Some large-sample Gaussian approximations are also considered. Iterative procedures for obtaining sampling probabilities yielding specified inclusion probabilities are discussed.

  • 14.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Mathematics and Mathematical Statistics.
    Contributions to the theory of unequal probability sampling2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis consists of five papers related to the theory of unequal probability sampling from a finite population. Generally, it is assumed that we wish to make modelassisted inference, i.e. the inclusion probability for each unit in the population is prescribed before the sample is selected. The sample is then selected using some random mechanism, the sampling design. Mostly, the thesis is focused on three particular unequal probability sampling designs, the conditional Poisson (CP-) design, the Sampford design, and the Pareto design. They have different advantages and drawbacks: The CP design is a maximum entropy design but it is difficult to determine sampling parameters which yield prescribed inclusion probabilities, the Sampford design yields prescribed inclusion probabilities but may be hard to sample from, and the Pareto design makes sample selection very easy but it is very difficult to determine sampling parameters which yield prescribed inclusion probabilities. These three designs are compared probabilistically, and found to be close to each other under certain conditions. In particular the Sampford and Pareto designs are probabilistically close to each other. Some effort is devoted to analytically adjusting the CP and Pareto designs so that they yield inclusion probabilities close to the prescribed ones. The result of the adjustments are in general very good. Some iterative procedures are suggested to improve the results even further. Further, balanced unequal probability sampling is considered. In this kind of sampling, samples are given a positive probability of selection only if they satisfy some balancing conditions. The balancing conditions are given by information from auxiliary variables. Most of the attention is devoted to a slightly less general but practically important case. Also in this case the inclusion probabilities are prescribed in advance, making the choice of sampling parameters important. A complication which arises in the context of choosing sampling parameters is that certain probability distributions need to be calculated, and exact calculation turns out to be practically impossible, except for very small cases. It is proposed that Markov Chain Monte Carlo (MCMC) methods are used for obtaining approximations to the relevant probability distributions, and also for sample selection. In general, MCMC methods for sample selection does not occur very frequently in the sampling literature today, making it a fairly novel idea.

  • 15.
    Lundquist, Anders
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    On the distance between some πps sampling designs2007In: Acta Applicandae Mathematicae - An International Survey Journal on Applying Mathematics and Mathematical Applications, ISSN 0167-8019, E-ISSN 1572-9036, Vol. 97, no 1-3, p. 79-97Article in journal (Refereed)
    Abstract [en]

    Asymptotic distances between probability distributions appearing in πps sampling theory are studied. The distributions are Poisson, Conditional Poisson (CP), Sampford, Pareto, Adjusted CP and Adjusted Pareto sampling. We start with the Kullback-Leibler divergence and the Hellinger distance and derive a simpler distance measure using a Taylor expansion of order two. This measure is evaluated first theoretically and then numerically, using small populations. The numerical examples are also illustrated using a multidimensional scaling technique called principal coordinate analysis (PCO). It turns out that Adjusted CP, Sampford, and adjusted Pareto are quite close to each other. Pareto is a bit further away from these, then comes CP and finally Poisson which is rather far from all the others.

  • 16.
    Lundquist, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Bondesson, Lennart
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    On sampling with desired inclusion probabilities of first and second order2005Report (Other academic)
    Abstract [en]

    We present a new simple approximation of target probabilities pi for conditional Poisson sampling to obtain given inclusion probabilities. This approximation is based on the fact that the Sampford design gives inclusion probabilities as desired. Some alternative routines to calculate exact pi-values are presented and compared numerically. Further we derive two methods for achieving prescribed 2nd order inclusion probabilities. First we use a probability function belonging to the exponential family. The parameters of this probability function are determined by using an iterative proportional fitting algorithm. Then we modify the conditional Poisson probability function with an additional quadratic factor.

  • 17.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Persson, Jonas
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Stockholm Brain Institute, Karolinska Institute, Stockholm, Sweden.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Karolinska Institute, Stockholm, Sweden.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Stockholm University, Stockholm Brain Institute.
    Age-related and genetic modulation of frontal cortex efficiency2014In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 26, no 4, p. 746-754Article in journal (Refereed)
    Abstract [en]

    The dorsolateral pFC (DLPFC) is a key region for working memory. It has been proposed that the DLPFC is dynamically recruited depending on task demands. By this view, high DLPFC recruitment for low-demanding tasks along with weak DLPFC upregulation at higher task demands reflects low efficiency. Here, the fMRI BOLD signal during working memory maintenance and manipulation was examined in relation to aging and catechol-O-methyltransferase (COMT) Val(158)Met status in a large representative sample (n = 287). The efficiency hypothesis predicts a weaker DLPFC response during manipulation, along with a stronger response during maintenance for older adults and COMT Val carriers compared with younger adults and COMT Met carriers. Consistent with the hypothesis, younger adults and met carriers showed maximal DLPFC BOLD response during manipulation, whereas older adults and val carriers displayed elevated DLPFC responses during the less demanding maintenance condition. The observed inverted relations support a link between dopamine and DLPFC efficiency.

  • 18.
    Nyberg, Lars
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Structural and functional imaging of aging: longitudinal sudies2017In: Cognitive neuroscience of aging: linking cognitive and cerebral aging / [ed] Roberto Cabeza, Lars Nyberg, and Denise C. Park, New York: Oxford University Press, 2017, 2, p. 155-182Chapter in book (Refereed)
    Abstract [en]

    This chapter on longitudinal structural and functional brain imaging examines points of convergence and divergence in findings from neuroimaging studies using cross-sectional versus longitudinal designs. Representative longitudinal age gradients are identified. It presents key methodological issues in longitudinal imaging, including test-retest effects, the influence of attrition, and different kinds of missing data. Various ways of handling data missingness in statistical analyses are also discussed.

  • 19.
    Pohl, Petra
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Ahlgren, Christina
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Nordin, Ellinor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Gender perspective on fear of falling using the classification of functioning as the model2015In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 37, no 3, p. 214-222Article in journal (Refereed)
    Abstract [en]

    Abstract Purpose: To investigate associations between fear of falling (FOF) and recurrent falls among women and men, and gender differences in FOF with respect to International Classification of Functioning (ICF). Methods: Community-dwelling people (n = 230, 75-93 years, 72% women) were included and followed 1 year regarding falls. Data collection included self-reported demographics, questionnaires, and physical performance-based tests. FOF was assessed with the question "Are you afraid of falling?". Results were discussed with a gender relational approach. Results: At baseline 55% women (n = 92) and 22% men (n = 14) reported FOF. During the follow-up 21% women (n = 35) and 30% men (n = 19) experienced recurrent falls. There was an association between gender and FOF (p = 0.001), but not between FOF and recurrent falls (p = 0.79), or between gender and recurrent falls (p = 0.32). FOF was related to Personal factors and Activity and Participation. The relationship between FOF and Personal factors was in opposite directions for women and men. Conclusions: Results did not support the prevailing paradigm that FOF increases rate of recurrent falls in community-dwelling people, and indicated that the answer to "Are you afraid of falling?" might be highly influenced by gendered patterns.

    Implications for Rehabilitation

    The question "Are you afraid of falling?" has no predictive value when screening for the risk of falling in independent community-dwelling women or men over 75 years of age.

    Gendered patterns might influence the answer to the question "Are you afraid of falling?" Healthcare personnel are recommended to be aware of this when asking older women and men about fear of falling.

  • 20.
    Pohl, Petra
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Nordin, Ellinor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Lundin-Olsson, Lillemor
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Community-dwelling older people with an injurious fall are likely to sustain new injurious falls within 5 years: a prospective long-term follow-up study2014In: BMC Geriatrics, ISSN 1471-2318, E-ISSN 1471-2318, Vol. 14, no 1, p. 120-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Fall-related injuries in older people are a leading cause of morbidity and mortality. Self-reported fall events in the last year is often used to estimate fall risk in older people. However, it remains to be investigated if the fall frequency and the consequences of the falls have an impact on the risk for subsequent injurious falls in the long term. The objective of this study was to investigate if a history of one single non-injurious fall, at least two non-injurious falls, or at least one injurious fall within 12 months increases the risk of sustaining future injurious falls.

    METHODS: Community-dwelling individuals 75-93 years of age (n = 230) were initially followed prospectively with monthly calendars reporting falls over a period of 12 months. The participants were classified into four groups based on the number and type of falls (0, 1, ≥2 non-injurious falls, and ≥1 injurious fall severe enough to cause a visit to a hospital emergency department). The participants were then followed for several years (mean time 5.0 years ±1.1) regarding injurious falls requiring a visit to the emergency department. The Andersen-Gill method of Cox regression for multiple events was used to estimate the risk of injurious falls.

    RESULTS: During the long-term follow-up period, thirty per cent of the participants suffered from at least one injurious fall. Those with a self-reported history of at least one injurious fall during the initial 12 months follow-up period showed a significantly higher risk for sustaining subsequent injurious falls in the long term (hazard ratio 2.78; 95% CI, 1.40-5.50) compared to those with no falls. No other group showed an increased risk.

    CONCLUSIONS: In community-dwelling people over 75 years of age, a history of at least one self-reported injurious fall severe enough to cause a visit to the emergency department within a period of 12 months implies an increased risk of sustaining future injurious falls. Our results support the recommendations to offer a multifactorial fall-risk assessment coupled with adequate interventions to community-dwelling people over 75 years who present to the ED due to an injurious fall.

  • 21.
    Salami, Alireza
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Kaboodvand, Neda
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center, Karolinska Institutet and Stockholm University, SE-113 30, Stockholm, Sweden.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Longitudinal Evidence for Dissociation of Anterior and Posterior MTL Resting-State Connectivity in Aging: Links to Perfusion and Memory2016In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 26, no 10, p. 3953-3963Article in journal (Refereed)
    Abstract [en]

    Neuroimaging studies of spontaneous signal fluctuations as measured by resting-state functional magnetic resonance imaging have revealed age-related alterations in the functional architecture of brain networks. One such network is located in the medial temporal lobe (MTL), showing structural and functional variations along the anterior-posterior axis. Past cross-sectional studies of MTL functional connectivity (FC) have yielded discrepant findings, likely reflecting the fact that specific MTL subregions are differentially affected in aging. Here, using longitudinal resting-state data from 198 participants, we investigated 5-year changes in FC of the anterior and posterior MTL. We found an opposite pattern, such that the degree of FC within the anterior MTL declined after age 60, whereas elevated FC within the posterior MTL was observed along with attenuated posterior MTL-cortical connectivity. A significant negative change-change relation was observed between episodic-memory decline and elevated FC in the posterior MTL. Additional analyses revealed age-related cerebral blood flow (CBF) increases in posterior MTL at the follow-up session, along with a positive relation of elevated FC and CBF, suggesting that elevated FC is a metabolically demanding alteration. Collectively, our findings indicate that elevated FC in posterior MTL along with increased local perfusion is a sign of brain aging that underlie episodic-memory decline.

  • 22.
    Sandvik, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Koskinen, Lars-Owe
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Thalamic and subthalamic DBS for essential tremor: where is the optimal target?2012In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 70, no 4, p. 840-846Article in journal (Refereed)
    Abstract [en]

    Background: The ventrolateral thalamus (Vim, ventral intermediate nucleus) is the traditional target for neurosurgical treatment of essential tremor (ET). The target has, however, varied substantially among different neurosurgeons.

    Objective: To evaluate the effect of deep brain stimulation (DBS) in the thalamus and posterior subthalamic area (PSA) in relation to electrode location.

    Methods: 36 (17Vim / 19 PSA) patients, with 44 DBS electrodes, were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the essential tremor rating scale (ETRS).

    Results: When each contact was evaluated regarding the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was in 54% located in the zona incerta (Zi) or radiation prelemniscalis (raprl) and in 12 % the Vim. 40 contacts provided a tremor reduction of >90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrandt atlas. 37 of these 40 contacts were found in the PSA group.

    Conclusion: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated upon in the Vim got the best effect in a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

  • 23.
    Sandvik, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Koskinen, Lars-Owe
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Thalamic and subthalamic deep brain stimulation for essential tremor: where is the optimal target?2012In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 70, no 4, p. 840-845Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The ventrolateral thalamus (ventral intermediate nucleus [ Vim]) is the traditional target for neurosurgical treatment of essential tremor. The target, however, has varied substantially among different neurosurgeons.

    OBJECTIVE: To evaluate the effect of deep brain stimulation in the thalamus and posterior subthalamic area (PSA) in relation to electrode location.

    METHODS: Thirty-six (17 Vim/19 PSA) patients with 44 deep brain stimulation electrodes were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the Essential Tremor Rating Scale.

    RESULTS: When each contact was evaluated in terms of the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was located in the zona incerta or radiation prelemniscalis in 54% and the Vim in 12%. Forty contacts provided a tremor reduction of > 90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrand atlas. Of these 40 contacts, 37 were found in the PSA group.

    CONCLUSION: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated on in the Vim got the best effect from a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

  • 24.
    Stenberg, Gunilla
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Fjellman-Wiklund, Anncristine
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Ahlgren, Christina
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Patterns of reported problems in women and men with back and neck pain: similarities and differences2014In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 46, no 7, p. 668-675Article in journal (Refereed)
    Abstract [en]

    Objective: To examine similarities and differences in problem areas reported by women and men who seek physiotherapy for back or neck pain. Methods: Principal component analysis (PCA) was used to analyse questionnaire data including demographics, pain, domestic work, stress, health status, physical disability, psychosocial and physical workload, kinesiophobia and self-efficacy. Most of the questions were recruited from a number of scales, e.g. EuroQol (EQ-5D), Neck Disability Index (NDI), Oswestry Disability Questionnaire (ODQ), Tampa Scale for Kinesiophobia, and Functional-Efficacy-Scale. Results: A total of 118 patients (84 women, 34 men) completed the questionnaire. Men and women scored similarly on physical disability, functional self-efficacy and kinesiophobia, but women scored higher on stress reactions and pain intensity. PCA showed that questions about physical disability and functional self-efficacy comprised the first component and explained most of the variance in this patient group. Questions about stress and social support at work constituted the second component. Questions about domestic workload and pain comprised the third component. Gender differences were found in the second and third components. Conclusion: In general, women and men answered questions similarly, but there were differences: more women reported stress, pain and low support at work and more men reported a lower domestic workload.

  • 25.
    Stenberg, Gunilla
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Fjellman-Wiklund, Anncristine
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Ahlgren, Christina
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Similarities and differences: patterns of reported problems and ICF classification in women and men with back or neck pain seeking physiotherapy treatmentManuscript (preprint) (Other academic)
    Abstract [en]

    Objective: The primary aim of this study was to examine similarities and differences in problem areas reported by women and men who seek physiotherapy treatment for back or neck pain. A second aim was to evaluate the appropriateness of ICF classification in relation to gender.

    Methods: Principal component analysis (PCA) and partial least squares of latent structures (PLS) were used to analyse questionnaire data including background data, questions about pain, domestic work, stress, EQ-5D, Neck Disability Index (NDI), Oswestry Disability Questionnaire (ODQ), psychosocial and physical workload, Tampa Scale and Functional Self-Efficacy Scale.

    Results: One hundred and eighteen patients (84 women and 34 men) completed the questionnaire. Men and women scored similarly on the NDI, ODQ, Functional Self Efficacy, and Tampa Scale, but women rated higher on stress reactions. PCA showed that questions from the NDI, ODQ and Functional Self-Efficacy Scale explained most of the variance in this patient group. Questions about stress and social support at work constituted the second component. Questions about domestic workload and pain comprised the third component. Gender differences were found in the two last components.

    Conclusion: Further investigation of the impact of gender on neck and back pain in different cultures is important.

  • 26.
    Stomby, Andreas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Region Jönköping County, Jönköping, Sweden.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Department of Psychology, Stockholm University, Stockholm, Sweden.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Higher diurnal salivary cortisol levels are related to smaller prefrontal cortex surface area in elderly men and women2016In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 175, no 2, p. 117-126Article in journal (Refereed)
    Abstract [en]

    Objective: Elevated cortisol levels with aging have been associated with atrophy of the hippocampus and prefrontal cortex (PFC), as well as with impaired cognitive functions in men. However, coexisting diseases have confounded many studies examining these relationships. Studies in women are lacking. Our objective was to test whether salivary cortisol levels were related to morphology of the hippocampus and the PFC, and to cognitive performance. Design: A cross-sectional study including 200 elderly (55-80 years old) men and women. Method: We used magnetic resonance imaging, tests of episodic-, semantic-, and working memory, visuospatial ability, and cortisol levels in four saliva samples collected during 1 day. Results: Area under the curve (AUC) for cortisol levels was negatively related to cortical surface area of the left anterior cingulate gyrus (caudal P < 0.001; rostral P = 0.006), right lateral orbitofrontal cortex (P = 0.004), and right rostral middle frontal gyrus (P = 0.003). In women, there was also a negative relationship with cortical surface area in the left rostral middle frontal gyrus (P = 0.006). No relationship was found between cortisol levels and hippocampal volume. Conclusion: This study suggests that the structure of the medial PFC is related to cortisol levels in both elderly women and men.

1 - 26 of 26
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