Conectividade estrutural cerebral, alfabetização e desempenho cognitivo em uma amostra de idosos da comunidade: estudo por análise de ressonância magnética utilizando imagens por tensor de difusão

Abstract

The association between white matter (WM) integrity, cognitive perfomance and cognitive reserve in elderly subjects is a challenging field of research. We applied magnetic resonance (MR) difusion tensor imaging (DTI) to investigate whether regional changes in WM integrity would impact on episodic memory perfomance and to evaluate the influence of education in WM microstructure in oldest-old individuals with low education living in community. Subjects were selected from the Pietá cohort, a community-based study on brain aging. Overall, 31 subjects(23 cognitively healthy and eight patients with cognitive impaiemnte-no dementia), being 22 women, aged 80.4 + ou .- 3.8 yearsm with 2. 2 + ou - 1.9 years of education, underwent a 3 tesla MR scanner with DTI acquisition. Diffusion sensitization gradients were applied to 32 non-collinear directions with b factor of 1000s/mm2. We cotrated literate (n=21) with iliterate subjects (n=10) and correlated the perfomance on the memory test from the Brief Cognitive Battery (BCB) and on the Rey Auditory Verbal learning Test (RAVLT) with fractional ansiotropy (FA) and mean diffusivity using both whole brain tract-based spatial statistics and regions of interest (ROI) approaches. Literate subjects had significantly higher FA. values in right superior longitudinal fasciculus in ROI analysis. BCB delayed recall task correlated positively with FA values in frontal temporal pariental connection bundles in whole brain and with cingulum-hippocampal part(CHC) bilaterally and right superior longitudinal fasciculus in ROI analysis. RAVLT A1-A5 sum of scores and RAVLT A7 score also correlated with CHC bilaterally, but only in ROI analysis. In conclusion, WM integrity correlated with episodic memory perfomance and was associated with literacy in the elderly living in community.