[P1–418]: DISTINCTIVE PATTERN OF CORTICAL THICKNESS AND WHITE MATTER INTEGRITY BETWEEN SPORADIC SVCI WITH AND WITHOUT NOTCH3 VARIANTS AND TYPICAL CADASIL

Background:Posterior cortical atrophy (PCA) is a rare progressive dementia syndrome characterized by prominent impairment of visuospatial and high visual cortical sense. The main pathology findings of PCA are beta-amyloid plaques and neurofibrillary tangles, which are the same with the Alzheimer’s disease. The aim of this study is to investigate clinical and neuroimaging characteristics of PCA compared to early-onset Alzheimer’s dementia (EOAD) via multidisciplinary approaches. Methods:We retrospectively recruited patients diagnosed as PCA and early-onset Alzheimer’s disease (EOAD) matching age and sex from 2011 to 2016. The clinical symptoms and signs associated with parieto-occipital lobar function such as elements of Balint syndrome, Gerstmann syndrome, alexia, apraxia, and visuospatial dysfunction were evaluated. The cognitive functions were evaluated with comprehensive neuropsychological tests. Neuroimaging including MRI, SPECTor FDG-PET, and amyloid PETwere performed to compare structural, functional and molecular neuroimaging findings including cortical atrophy, hypofunctional regions, and amyloid pathology on brain. We used Chi-square and Kruskal Wallis test for analysis, Mann-whitney U test for post hoc analysis using SPSS version 23. Results: Nine PCA cases and 11 EOAD cases were included. Clinically, the elements of Balint syndrome such as simultanagnosia, optic ataxia, oculomotor apraxia and the elements of Gerstmann syndrome such as left/right disorientation, dysgraphia and dyscalculia, as well as dressing apraxia, ideomotor apraxia, visual agnosia, spatial disorientation, and alexia were dominant in PCA group, satisfying clinical diagnostic criteria. On neuropsychological tests, digit span forward (p1⁄40.006) and Rey Figure copy test (p1⁄40.020)weremore impaired in PCA thanEOAD (p1⁄40.006). Verbal delayed recall was more impaired in EOAD compared with that in PCA (p1⁄40.031). Brain MRI showed higher of medial temporal lobe atrophy scores in EOAD (p1⁄40.014) although there was no difference on Generalized atrophy score (P1⁄40.540, p1⁄40.577) or Parietal atrophy score (p1⁄40.227). Functional imaging showed more parietooccipital hypofunction indicated in PCA (p1⁄40.008). However, amyloid PET showed equally positive in both groups. Conclusions: These findings suggest that the clinical features of PCA arewell correlated with the prominent parieto-occipital hypoperfusions and relatively spared medial temporal lobe, while amyloid burden and deposition patterns did not show significant difference between PCA and EOAD.