| 81. |
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| 82. |
- Persson, J, et al.
(författare)
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Altered brain white-matter integrity in non-demented carriers of the APOE ε4 allele: A risk for Alzheimer’s disease.
- 2006
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 66:7, s. 1029-1033
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Tidskriftsartikel (refereegranskat)abstract
- Previous research has shown that polymorphisms of the apolipoprotein E (APOE) represent genetic risk factors for dementia and for cognitive impairment in the elderly. The neural mechanisms by which these genetic variations influence behavioral performance or clinical severity are not well understood. We used diffusion tensor imaging to investigate ultrastructural properties in brain white-matter to detect pathological processes that modify tissue integrity. Sixty participants were included in the study of which 30 were homozygous for the APOE ε3 allele, 10 were homozygous for the APOE ε4 allele, and 20 had the APOE ε34 allele combination. All individuals were non-demented, and the groups were matched on demographic variables and cognitive performance. The results showed a decline in fractional anisotropy, a marker for white-matter integrity, in the posterior corpus callosum of ε4 carriers compared to non-carriers. Additional sites of altered white-matter integrity included the medial temporal lobe. Conclusions: Although the mechanism underlying vulnerability of white matter tracts in APOE ε4 carriers is still unknown, our findings suggest that increased genetic risk for developing AD is associated with changes in microscopic white-matter integrity well before the onset of dementia.
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| 83. |
- Persson, Jonas, et al.
(författare)
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Altered deactivation in individuals with genetic risk for Alzheimer's disease
- 2008
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Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 46:6, s. 1679-1687
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Tidskriftsartikel (refereegranskat)abstract
- Regions that show task-induced deactivations may be part of a default-mode network related to processes that are more engaged during passive than active task conditions. Alteration of task-induced deactivations with age and dementia is indicated by atypical engagement of default-mode network regions. Genetic studies show a relation between the apolipoprotein E4 (APOE4) allele and the common form of Alzheimer’s disease (AD), and altered functional brain activation has been observed in non-demented APOE4 carriers compared to non-carriers. Here we investigate the hypothesis of altered default-mode network brain responses in individuals with genetic risk for AD. Functional MRI was used to assess task-induced deactivation in 60 subjects of which 30 carried at least one copy of the APOE4 allele, and 30 non-carriers. Subjects were scanned while performing a semantic categorization task shown to promote episodic memory encoding. The results show patterns of deactivation consistent with the default-mode network. We also found reduced deactivation in non-demented APOE4 carriers compared to non-carriers, suggesting alterations in the default-mode network in the absence of dementia. These results implicate possibilities for investigatin altered properties of task-induced deactivations in individuals with genetic risk for AD, and may prove useful for pre-clinical identification of individuals susceptible to memory problems and AD.
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| 84. |
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| 85. |
- Sundström, Anna, 1969-, et al.
(författare)
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APOE influences on neurosychological function after mild head injury : within-person comparisons
- 2004
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Ingår i: Neurology. - Minneapolis, Minn : Lancet Publications Inc.. - 0028-3878 .- 1526-632X. ; 62:11, s. 1963-1966
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the relationship between neuropsychological outcome following mild head injury (MHI) and APOE genotype. Methods: Data from a population-based longitudinal study (n = 3,500) were used to identify 34 adults who experienced MHI during the course of the study. Their pre- and postinjury performances on a battery of nine neuropsychological tests were compared within person, and the postinjury performance was compared with that of age- and gender-matched control subjects. Results: The within-person comparisons showed that participants with at least oneAPOE ε4 allele (n = 11) had a significantly decreased postinjury performance on three of the tests, whereas the postinjury performance for APOE ε4-negative participants (n = 23) was unchanged. There was no significant difference in postinjury performance between participants with/without the ε4 allele, and neither group was impaired relative to controls. Conclusions: APOE genotype may influence the outcome following an MHI. Pre/postinjury within-person comparisons seem more sensitive than control group comparisons for detecting injury-related effects.
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| 86. |
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| 87. |
- Sundström, Anna, 1969-, et al.
(författare)
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Increased risk of dementia following mild head injury for carriers but not for non-carriers of the APOE ε4 allele
- 2007
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Ingår i: International psychogeriatrics. - New York : Springer. - 1041-6102 .- 1741-203X. ; 19:1, s. 159-165
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Tidskriftsartikel (refereegranskat)abstract
- Background: The ε4 allele of apolipoprotein E (APOE) and head injury are risk factors for dementia diseases, and may act synergistically to further increase the risk. The aim of this study was to examine the association between mild head injury, APOE and dementia.Methods: Data were obtained from the Betula prospective population-based study of aging, memory, and health. The study included 543 participants in the age range 40–85 years, free of dementia at baseline, who were followed up within a 5-year interval. Dementia was classified using DSM-IV criteria. Information on previous head injury was obtained through screening of the participants' answers to health questionnaires at baseline and at follow-up.Results: Subjects with head injury but without APOE ε4 had no increased risk of dementia. Subjects with APOE ε4 had an increased risk and those with both APOE ε4 and head injury had the highest risk of dementia (odds ratio = 5.2).Conclusions: APOE ε4 constitutes a risk factor for dementia, mild injury in isolation does not increase the risk, but head injury in combination with the APOE ε4 leads to increased risk of dementia.
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