Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
1.
J Neural Transm (Vienna) ; 122(11): 1581-92, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26253899

RESUMO

Variations of the cholesteryl ester transfer protein polymorphism (CETP I405V/rs5882) have been associated with an increased risk for neurodegeneration, particularly when examined in conjunction with the epsilon 4 isoform of apolipoprotein E (ApoE4). Despite these identified relationships, the impact of I405V on gray matter microstructure remains unknown. The present study examined the impact of the CETP I405V polymorphism on gray matter integrity among 52 healthy adults between ages 51 and 85. Gray matter was measured bilaterally using diffusion tensor imaging (DTI) metrics of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Participants were grouped according to a dominant statistical model (II genotype vs. IV/VV genotypes) and secondary analyses were completed to examine the interactive effects of CETP and ApoE4 on DTI metrics. Compared to individuals with the IV/VV genotypes, II homozygotes demonstrated significantly higher MD in bilateral temporal, parietal, and occipital gray matter. Secondary analyses revealed higher FA and AD in the left temporal lobe of IV/VV genotypes with an ApoE4 allele. Our results provide preliminary evidence that CETP II homozygosity is a predisposing risk factor for gray matter abnormalities in posterior brain regions in healthy older adults, independent of an ApoE4 allele.


Assuntos
Transporte Biológico/genética , Encéfalo/metabolismo , Proteínas de Transferência de Ésteres de Colesterol/genética , Colesterol/metabolismo , Substância Cinzenta/metabolismo , Polimorfismo Genético , Idoso , Idoso de 80 Anos ou mais , Anisotropia , Apolipoproteínas E/genética , Encéfalo/patologia , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Feminino , Genótipo , Técnicas de Genotipagem , Substância Cinzenta/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Genéticos , Modelos Estatísticos
2.
Brain Imaging Behav ; 10(1): 203-11, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25864197

RESUMO

Aging is associated with microstructural changes in brain tissue that can be visualized using diffusion tensor imaging (DTI). While previous studies have established age-related changes in white matter (WM) diffusion using DTI, the impact of age on gray matter (GM) diffusion remains unclear. The present study utilized DTI metrics of mean diffusivity (MD) to identify age differences in GM/WM microstructure in a sample of healthy older adults (N = 60). A secondary aim was to determine the functional significance of whole-brain GM/WM MD on global cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Participants were divided into three age brackets (ages 50-59, 60-69, and 70+) to examine differences in MD and cognition by decade. MD was examined bilaterally in the frontal, temporal, parietal, and occipital lobes for the primary analyses and an aggregate measure of whole-brain MD was used to test relationships with cognition. Significantly higher MD was observed in bilateral GM of the temporal and parietal lobes, and in right hemisphere WM of the frontal and temporal lobes of older individuals. The most robust differences in MD were between the 50-59 and 70+ age groups. Higher whole-brain GM MD was associated with poorer RBANS performance in the 60-69 age group. Results suggest that aging has a significant and differential impact on GM/WM diffusion in healthy older adults, which may explain a modest degree of cognitive variability at specific time points during older adulthood.


Assuntos
Envelhecimento/patologia , Encéfalo/diagnóstico por imagem , Substância Cinzenta/diagnóstico por imagem , Idoso , Envelhecimento/psicologia , Encéfalo/patologia , Cognição , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Feminino , Substância Cinzenta/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Testes Psicológicos
3.
Clin Neuropsychol ; 29(6): 824-35, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26373627

RESUMO

OBJECTIVE: The Montreal Cognitive Assessment (MoCA) is a brief screening measure commonly used to determine cognitive status among older adults. Despite the popularity of the MoCA, there has been little research into how performance on the MoCA changes over time in healthy older adults. METHODS: The present study examined a sample of older adults (n = 53) recruited for a longitudinal study of healthy aging. Change in total MoCA score at three time points (baseline, 12 months, and 48 months) and scores from the Repeatable Battery for the Assessment of Neuropsychological Status at five time points (RBANS; baseline 12 months, 24 months, 36 months, and 48 months) were assessed using repeated measures analyses. RESULTS: Total MoCA score significantly increased across time, particularly between the first and second administrations. Scores did not significantly differ between the second (12 month) and third (48 month) administrations. When grouped by baseline performance, individuals who scored low at baseline significantly improved performance at 12-month testing, but had little change between 12- and 48-month testing. Conversely, individuals who scored high at baseline did not significantly change between baseline and 12-month testing, but improved between 12- and 48-month testing. RBANS scores did not significantly change over time. CONCLUSIONS: These results suggest that the MoCA may be susceptible to practice effects, particularly between the first and second administrations. These practice effects should be taken into consideration when repeatedly employing the MoCA to screen for cognitive status in healthy older adults.


Assuntos
Cognição/fisiologia , Testes Neuropsicológicos/normas , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos de Pesquisa
4.
J Clin Exp Neuropsychol ; 37(1): 61-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25523313

RESUMO

OBJECTIVE: Much of the mild cognitive impairment (MCI) neuroimaging literature has exclusively focused on regions associated with Alzheimer's disease. Little research has examined white matter abnormalities of other brain regions, including those associated with visual processing, despite evidence that other brain abnormalities appear in these regions in early disease stages. METHOD: Diffusion tensor imaging (DTI) was utilized to examine participants (n = 44) that completed baseline imaging as part of a longitudinal healthy aging study. Participants were divided into two groups based on scores from the Montreal Cognitive Assessment (MoCA), a brief screening tool for MCI. Participants who scored <26 were defined as "probable MCI" while those who scored ≥26 were labeled cognitively healthy. Two DTI indices were analyzed including fractional anisotropy (FA) and mean diffusivity (MD). DTI values for white matter in the lingual gyrus, cuneus, pericalcarine, fusiform gyrus, and all four lobes were compared using multivariate analysis of variance (MANOVA). Regression analyses examined the relationship between DTI indices and total MoCA score. RESULTS: RESULTS revealed significantly lower FA in the probable MCI group in the cuneus, fusiform, pericalcarine, and occipital lobe, and significantly higher MD in the temporal lobe. Fusiform FA and temporal lobe MD were significantly related to total MoCA score after accounting for age and education. CONCLUSIONS: RESULTS indicate that there are posterior white matter microstructural changes in individuals with probable MCI. These differences demonstrate that white matter abnormalities are evident among individuals with probable MCI in regions beyond those commonly associated with Alzheimer's disease and anterior brain aging patterns.


Assuntos
Encéfalo/patologia , Disfunção Cognitiva/patologia , Substância Branca/patologia , Idoso , Anisotropia , Imagem de Tensor de Difusão , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Testes Neuropsicológicos , Análise de Regressão
5.
Behav Brain Res ; 278: 342-7, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25448431

RESUMO

Obesity, commonly measured with body mass index (BMI), is associated with numerous deleterious health conditions including alterations in brain integrity related to advanced age. Prior research has suggested that white matter integrity observed using diffusion tensor imaging (DTI) is altered in relation to high BMI, but the integrity of specific white matter tracts remains poorly understood. Additionally, no studies have examined white matter tract integrity in conjunction with neuropsychological evaluation associated with BMI among older adults. The present study examined white matter tract integrity using DTI and cognitive performance associated with BMI in 62 healthy older adults (20 males, 42 females) aged 51-81. Results revealed that elevated BMI was associated with lower fractional anisotropy (FA) in the uncinate fasciculus, though there was no evidence of an age by BMI interaction relating to FA in this tract. No relationships were observed between BMI and other white matter tracts or cognition after controlling for demographic variables. Findings suggest that elevated BMI is associated with lower structural integrity in a brain region connecting frontal and temporal lobes and this alteration precedes cognitive dysfunction. Future studies should examine biological mechanisms that mediate the relationships between BMI and white matter tract integrity, as well as the evolution of these abnormalities utilizing longitudinal designs.


Assuntos
Índice de Massa Corporal , Encéfalo/anatomia & histologia , Cognição/fisiologia , Idoso , Idoso de 80 Anos ou mais , Imagem de Tensor de Difusão , Função Executiva/fisiologia , Feminino , Humanos , Masculino , Memória/fisiologia , Entrevista Psiquiátrica Padronizada , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estatística como Assunto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA