| 1. |
- Wang, Rui, et al.
(författare)
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MRI load of cerebral microvascular lesions and neurodegeneration, cognitive decline, and dementia
- 2018
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Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 91:16, s. 1487-1497
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Tidskriftsartikel (refereegranskat)abstract
- Objective To explore the differential associations of neurodegeneration and microvascular lesion load with cognitive decline and dementia in older people and the modifying effect of the APOE genotype on these associations. Methods A sample of 436 participants (age >= 60 years) was derived from the population-based Swedish National study on Aging and Care in Kungsholmen, Stockholm, and clinically examined at baseline (2001-2003) and 3 occasions during the 9-year follow-up. At baseline, we assessed microvascular lesion load using a summary score for MRI markers of lacunes, white matter hyperintensities (WMHs), and perivascular spaces and neurodegeneration load for markers of enlarged ventricles, smaller hippocampus, and smaller gray matter. We assessed cognitive function using the Mini-Mental State Examination (MMSE) test and diagnosed dementia following the Diagnostic and Statistical Manual of Mental Disorders, 4th edition criteria. We analyzed data using linear mixed-effects, mediation, and random-effects Cox models. Results During the follow-up, 46 participants were diagnosed with dementia. Per 1-point increase in microvascular lesion and neurodegeneration score (range 0-3) was associated with multiple adjusted beta-coefficients of -0.35 (95% confidence interval, -0.51 to -0.20) and -0.44 (-0.56 to -0.32), respectively, for the MMSE score and multiple adjusted hazard ratios of 1.68 (1.12-2.51) and 2.35 (1.58-3.52), respectively, for dementia; carrying APOE epsilon 4 reinforced the associations with MMSE decline. WMH volume changes during the follow-up mediated 66.9% and 12.7% of the total association of MMSE decline with the baseline microvascular score and neurodegeneration score, respectively. Conclusions Both cerebral microvascular lesion and neurodegeneration loads are strongly associated with cognitive decline and dementia. The cognitive decline due to microvascular lesions is exacerbated by APOE epsilon 4 and is largely attributed to progression and development of microvascular lesions.
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| 2. |
- Kivipelto, Miia, et al.
(författare)
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The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) : Study design and progress
- 2013
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 9:6, s. 657-665
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Tidskriftsartikel (refereegranskat)abstract
- Background: Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) is a multi-center, randomized, controlled trial ongoing in Finland. Materials: Participants (1200 individuals at risk of cognitive decline) are recruited from previous population-based non-intervention studies. Inclusion criteria are CAIDE Dementia Risk Score >= 6 and cognitive performance at the mean level or slightly lower than expected for age (but not substantial impairment) assessed with the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery. The 2-year multidomain intervention consists of: nutritional guidance; exercise; cognitive training and social activity; and management of metabolic and vascular risk factors. Persons in the control group receive regular health advice. The primary outcome is cognitive performance as measured by the modified Neuropsychological Test Battery, Stroop test, and Trail Making Test. Main secondary outcomes are: dementia (after extended follow-up); disability; depressive symptoms; vascular risk factors and outcomes; quality of life; utilization of health resources; and neuroimaging measures. Results: Screening began in September 2009 and was completed in December 2011. All 1200 persons are enrolled and the intervention is ongoing as planned. Baseline clinical characteristics indicate that several vascular risk factors and unhealthy lifestyle related factors are present, creating a window of opportunity for prevention. The intervention will be completed during 2014. Conclusions: The FINGER is at the forefront of international collaborative efforts to solve the clinical and public health problems of early identification of individuals at increased risk of late-life cognitive impairment, and of developing intervention strategies to prevent or delay the onset of cognitive impairment and dementia.
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| 3. |
- Gallo, Federico, et al.
(författare)
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Cognitive Trajectories and Dementia Risk : A Comparison of Two Cognitive Reserve Measures.
- 2021
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media S.A.. - 1663-4365. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objectives: Cognitive reserve (CR) is meant to account for the mismatch between brain damage and cognitive decline or dementia. Generally, CR has been operationalized using proxy variables indicating exposure to enriching activities (activity-based CR). An alternative approach defines CR as residual variance in cognition, not explained by the brain status (residual-based CR). The aim of this study is to compare activity-based and residual-based CR measures in their association with cognitive trajectories and dementia. Furthermore, we seek to examine if the two measures modify the impact of brain integrity on cognitive trajectories and if they predict dementia incidence independent of brain status.Methods: We used data on 430 older adults aged 60+ from the Swedish National Study on Aging and Care in Kungsholmen, followed for 12 years. Residual-based reserve was computed from a regression predicting episodic memory with a brain-integrity index incorporating six structural neuroimaging markers (white-matter hyperintensities volume, whole-brain gray matter volume, hippocampal volume, lateral ventricular volume, lacunes, and perivascular spaces), age, and sex. Activity-based reserve incorporated education, work complexity, social network, and leisure activities. Cognition was assessed with a composite of perceptual speed, semantic memory, letter-, and category fluency. Dementia was clinically diagnosed in accordance with DSM-IV criteria. Linear mixed models were used for cognitive change analyses. Interactions tested if reserve measures modified the association between brain-integrity and cognitive change. Cox proportional hazard models, adjusted for brain-integrity index, assessed dementia risk.Results: Both reserve measures were associated with cognitive trajectories [β × time (top tertile, ref.: bottom tertile) = 0.013; 95% CI: -0.126, -0.004 (residual-based) and 0.011; 95% CI: -0.001, 0.024, (activity-based)]. Residual-based, but not activity-based reserve mitigated the impact of brain integrity on cognitive decline [β (top tertile × time × brain integrity) = -0.021; 95% CI: -0.043, 0.001] and predicted 12-year dementia incidence, after accounting for the brain-integrity status [HR (top tertile) = 0.23; 95% CI: 0.09, 0.58].Interpretation: The operationalization of reserve based on residual cognitive performance may represent a more direct measure of CR than an activity-based approach. Ultimately, the two models of CR serve largely different aims. Accounting for brain integrity is essential in any model of reserve.
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| 4. |
- Lövdén, Martin, et al.
(författare)
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The dimensionality of between-person differences in white matter microstructure in old age
- 2013
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Ingår i: Human Brain Mapping. - : Wiley. - 1065-9471 .- 1097-0193. ; 34:6, s. 1386-1398
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Tidskriftsartikel (refereegranskat)abstract
- Between-person differences in white matter microstructure may partly generalize across the brain and partly play out differently for distinct tracts. We used diffusion-tensor imaging and structural equation modeling to investigate this issue in a sample of 260 adults aged 60–87 years. Mean fractional anisotropy and mean diffusivity of seven white matter tracts in each hemisphere were quantified. Results showed good fit of a model positing that individual differences in white matter microstructure are structured according to tracts. A general factor, although accounting for variance in the measures, did not adequately represent the individual differences. This indicates the presence of a substantial amount of tract-specific individual differences in white matter microstructure. In addition, individual differences are to a varying degree shared between tracts, indicating that general factors also affect white matter microstructure. Age-related differences in white matter microstructure were present for all tracts. Correlations among tract factors did not generally increase as a function of age, suggesting that aging is not a process with homogenous effects on white matter microstructure across the brain. These findings highlight the need for future research to examine whether relations between white matter microstructure and diverse outcomes are specific or general. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.
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| 5. |
- Li, Xin, et al.
(författare)
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The relationship of age and DRD2 polymorphisms to frontostriatal brain activity and working memory performance
- 2019
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 84, s. 189-199
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Tidskriftsartikel (refereegranskat)abstract
- Dopamine (DA) in both prefrontal cortex (PFC) and caudate nucleus is critical for working memory (WM) function. The C957T and Taq1A polymorphisms of the DRD2 gene are related to DA D2 receptor densities in PFC and striatum. Using functional MRI, we investigated the relationship of age and these 2 DRD2 gene polymorphisms to WM function and examined possible age by gene interactions. Results demonstrated less caudate activity for older adults (70-80 years; n = 112) compared with the younger age group (25-65 years; n = 191), suggesting age-related functional differences in this region. Importantly, there was a gene-related difference regarding WM performance and frontostriatal brain activity. Specifically, better WM performance and greater activity in PFC were found among C957T C allele carriers. Combined genetic markers for increased DA D2 receptor density were associated with greater caudate activity and higher WM updating performance. The genetic effects on blood oxygen level-dependent activity were only observed in older participants, suggesting magnified genetic effects in aging. Our findings emphasize the importance of DA-related genes in regulating WM functioning in aging and demonstrate a positive link between DA and brain activation in the frontostriatal circuitry.
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| 6. |
- Li, Xin, et al.
(författare)
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White-matter integrity and working memory : Links to aging and dopamine-related genes
- 2022
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Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Working memory, a core function underlying many higher-level cognitive processes, requires cooperation of multiple brain regions. White matter refers to myelinated axons, which are critical to inter-regional brain communication. Past studies on the association between white-matter integrity and working memory have yielded mixed findings. Using voxel-wise tract-based spatial statistics analysis, we investigated this relationship in a sample of 328 healthy adults from 25 to 80 years of age. Given the important role of dopamine (DA) in working-memory functioning and white matter, we also analyzed the effects of dopamine-related genes on them. There were associations between white-matter integrity and working memory in multiple tracts, indicating that working-memory functioning relies on global connections between different brain areas across the adult lifespan. Moreover, a mediation analysis suggested that white-matter integrity contributes to age-related differences in working memory. Finally, there was an effect of the COMT Val158Met polymorphism on white-matter integrity, such that Val/Val carriers had lower fractional anisotropy (FA) values than any Met carriers in the internal capsule, corona radiata, and posterior thalamic radiation. As this polymorphism has been associated with dopaminergic tone in the prefrontal cortex (PFC), this result provides evidence for a link between DA neurotransmission and white matter. Taken together, the results support a link between white-matter integrity and working memory and provide evidence for its interplay with age and DA-related genes.
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| 7. |
- Salami, Alireza, et al.
(författare)
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Dopamine D-2/3 Binding Potential Modulates Neural Signatures of Working Memory in a Load-Dependent Fashion
- 2019
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 39:3, s. 537-547
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Tidskriftsartikel (refereegranskat)abstract
- Dopamine (DA) modulates corticostriatal connections. Studies in which imaging of the DA system is integrated with functional imaging during cognitive performance have yielded mixed findings. Some work has shown a link between striatal DA(measured by PET) and fMRI activations, whereas others have failed to observe such a relationship. One possible reason for these discrepant findings is differences in task demands, such that a more demanding task with greater prefrontal activations may yield a stronger association with DA. Moreover, a potential DA-BOLD association may be modulated by task performance. We studied 155 (104 normal-performing and 51 low-performing) healthy older adults (43% females) who underwent fMRI scanning while performing a working memory (WM) n-back task along with DA D-2/3 PET assessment using [C-11] raclopride. Using multivariate partial-least-squares analysis, we observed a significant pattern revealing positive associations of striatal as well as extrastriatal DA D-2/3 receptors to BOLD response in the thalamo-striatalcortical circuit, which supports WM functioning. Critically, the DA-BOLD association in normal-performing, but not low-performing, individuals was expressed in a load-dependent fashion, with stronger associations during 3-back than 1-/2-back conditions. Moreover, normal-performing adults expressing upregulated BOLD in response to increasing task demands showed a stronger DA-BOLD association during 3-back, whereas low-performing individuals expressed a stronger association during 2-back conditions. This pattern suggests a nonlinear DA-BOLD performance association, with the strongest link at the maximum capacity level. Together, our results suggest that DA may have a stronger impact on functional brain responses during more demanding cognitive tasks.
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| 8. |
- Ekström, Ingrid, et al.
(författare)
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Predictors of cognitive aging profiles over 15 years : a longitudinal population-based study
- 2024
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 39:5, s. 467-483
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Tidskriftsartikel (refereegranskat)abstract
- The present study aimed to characterize profiles of cognitive aging and how these can be predicted frominterindividual differences in demographic, lifestyle, health, and genetic factors. The participants were1,966 older adults (mean baseline age= 71.6 years; 62.9% female), free from dementia at baseline and with atleast two cognitive assessments over the 15-year follow-up, from the population-based Swedish NationalStudy on Aging and Care in Kungsholmen. The cognitive assessment comprised tests of semantic andepisodic memory, letter and category fluency, perceptual speed, and executive function. First, we estimatedthe level and change within each of the cognitive domains with linear mixed effect models, based on whichwe grouped our sample into participants with “maintained high cognition,” “moderate cognitive decline,” or“accelerated cognitive decline.” Second, we analyzed determinants of group membership within eachcognitive domain with multinomial logistic regression. Third, group memberships within each cognitivedomain were used to derive general cognitive aging profiles with latent class analysis. Fourth, thedeterminants of these profile memberships were analyzed with multinomial logistic regression. Follow-upanalyses targeted profiles and predictors specifically related to the rate of cognitive change. We identifiedthree latent profiles of overall cognitive performance during the follow-up period with 31.6% of the samplehaving maintained high cognition, 50.6% having moderate cognitive decline, and 17.8% having acceleratedcognitive decline. In multiadjusted analyses, maintained high cognition was predicted by female sex, highereducation, and faster walking speed. Smoking, loneliness, and being an ε4 carrier were associated with alower likelihood of maintained high cognition. Higher age, diagnosis of diabetes, depression, and carryingthe apolipoprotein E ε4 allele increased the likelihood of accelerated cognitive decline. Factors at baselinethat could significantly predict profile membership within the specific cognitive domains included age, sex,years of education, walking speed, diabetes, and the ε4 allele. Of note, these factors differed across cognitivedomains. In sum, we identified demographic, lifestyle, health, and genetic factors of interindividualdifferences in domain-specific and general cognitive aging profiles, some of which are modifiable.
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| 9. |
- Köhncke, Ylva, et al.
(författare)
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Self-rated intensity of habitual physical activities is positively associated with dopamine D-2/3 receptor availability and cognition
- 2018
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 181, s. 605-616
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Tidskriftsartikel (refereegranskat)abstract
- Between-person differences in cognitive performance in older age are associated with variations in physical activity. The neurotransmitter dopamine (DA) contributes to cognitive performance, and the DA system deteriorates with advancing age. Animal data and a patient study suggest that physical activity modulates DA receptor availability, but data from healthy humans are lacking. In a cross-sectional study with 178 adults aged 64-68 years, we investigated links among self-reported physical activity, D(2/3)DA receptor (D2/3DR) availability, and cognitive performance. D2/3DR availability was measured with [C-11]raclopride positron emission tomography at rest. We used structural equation modeling to obtain latent factors for processing speed, episodic memory, working memory, physical activity, and D2/3DR availability in caudate, putamen, and hippocampus. Physical activity intensity was positively associated with D2/3DR availability in caudate, but not putamen and hippocampus. Frequency of physical activity was not related to D2/3DR availability. Physical activity intensity was positively related to episodic memory and working memory. D2/3DR availability in caudate and hippocampus was positively related to episodic memory. Taken together, our results suggest that striatal DA availability might be a neurochemical correlate of episodic memory that is also associated with physical activity.
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| 10. |
- Larsson, Maria, et al.
(författare)
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Olfactory memory in the old and very old : relations to episodic and semantic memory and APOE genotype
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 38, s. 118-126
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Tidskriftsartikel (refereegranskat)abstract
- The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE epsilon 4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups.
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