CORRELATIONS BETWEEN VARIOUS MOCA COGNITIVE DOMAIN ASSESSMENTS AND REGIONAL BRAIN FDG-PET HYPOMETABOLISM

Abstract

Cognitive deficiencies correlate with regional brain hypometabolism. The Montreal Cognitive Assessment (MoCA) is widely utilized for MCI. Subscores of the MoCA were found to be strong predictors of conversion from MCI to AD over 18 months. We examined correlations between total MoCA, its subtest scores and [18F]FDG-PET, and the predictive value of MoCA subtest scores for global hypometabolism two years later. A total of 160 subjects (CN 54, MCI 128, AD 31) were included from the ADNI dataset. MoCA and FDG-PET scan were obtained in the same individuals not more than 6 months apart at the baseline and two-year follow-up visits. MoCA assessment was classified into 6 subtests, language index score (LIS), memory index score (MIS), attention index score (AIS), visuospatial index score (VIS), executive index score (EIS) and orientation index score (OIS). Voxel-based SUVR maps for [18F]FDG were calculated using pons as reference region. Global SUV was estimated as the median SUVR value obtained using masks encompassing fronto-temporo-parietal regions. Voxel-based and regression analysis were conducted between total MoCA, subtest scores and [18F]FDG. Each correlation was corrected for age, gender and education. Demographics in Table 1. The associations between total MoCA score and [18F]FDG showed scattered correlations on temporal, frontal and parietal cortices (Figure 1). LIS was associated with [18F]FDG on Broca's area, premotor cortex and inferior frontal gyrus; MIS, with hippocampus and posterior cingulate cortex (PCC); EIS, with hippocampus and medial temporal gyrus; OIS and AIS, with all cortical area, except occipital cortex, brain stem and cerebellum; VIS, with a small area on inferior parietal and inferior temporal cortex. Comparing between groups, CN and AD groups showed correlation between total MoCA scores and [18F]FDG in the frontal area, with the AD group showing a higher correlation. In contrast, MCI group showed scattered correlation in frontal, temporal, precuneus and PCC. Total MoCA scores or subtest scores at baseline did not predict global hypometabolism two years later in that dataset.