A - 59 Regional Cerebral Metabolism Is Associated with Performance on the Visual Object and Space Perception Battery in those with Posterior Cortical Atrophy.

Abstract

Posterior cortical atrophy (PCA) is a relatively rare clinical syndrome characterized by visuoperceptual/spatial dysfunction with relatively preserved memory, language, and insight in the early stages. Thus, PCA provides a unique population through which to evaluate structure-function relationships for commonly used neuropsychological tests. Here, we evaluated relationships between fluorodeoxyglucose (FDG) positron emission tomography (PET) and performance on the Visual Object and Space Perception (VOSP) Battery. Ten participants with an established diagnosis of PCA underwent baseline neuropsychological testing that included the VOSP, FDG-PET, and structural MRI. We used FreeSurfer to identify anatomical structures in the structural MRI scans, aligned the MRI and PET scans, and then extracted FDG signal from these same regions. Several brain regions relevant for PCA were a priori targeted. We evaluated relationships between the regional FDG values and VOSP performances using Spearman's rank correlation. Silhouettes, Dot Counting, and Number Location showed strong relationships with the superior parietal lobule bilaterally. The right superior parietal lobule showed moderate to strong relationships with Incomplete Letters and Progressive Silhouettes, whereas the left superior parietal lobule showed a strong relationship with Object Decision. Incomplete letters showed a strong relationship with the right supramarginal gyrus. Silhouettes showed a strong relationship with the left fusiform gyrus. These findings from a relatively rare and heterogeneous syndrome provide insight into the regional contributions to visuospatial functioning. Future work will evaluate network-level integrity with these tasks in order to further clarify structure-function relationships.