PATTERNS OF HIPPOCAMPAL SHAPE CHANGES IN PATIENTS WITH FRONTOTEMPORAL DEMENTIA

Abstract

one and two-year hippocampal atrophy and cortical atrophy in CN and MCI subjects in the Alzheimer ’s disease Neuroimaging Initiative (ADNI) using a registration-based cube propagation method. Among 504 subjects with 234 MCI, and 169 CN, we defined apriori a group with predominant hippocampal atrophy at year one (>1 standard deviation of the hippocampal atrophy of the population and<1 standard deviation of the cortical atrophy). We tested two hypotheses 1) Subjects meeting criteria at year one are consistent in their atrophy pattern at year two. 2) Subjects with stable hippocampal predominant atrophy have slower functional decline on (Clinical Dementia Rating Scale: Sum of Boxes (CDR-SB). Results: 110 subjects met criteria for hippocampal predominant atrophy. Among these 52% (57 subjects) meeting criteria at year one remain in the same group at year two i.e., with persistent hippocampal predominant atrophy. At baseline, persistent hippocampal atrophy group had a lower CDR SB mean than the non-persistent hippocampal atrophy group (1.1 vs. 1.9, p<0.001). In a linear regression with CDR-SB scores as outcome and controlling for age, sex, education and APOE, persistent hippocampal atrophy group had a slower decline in the CDR SB scores over a year than the non-persistent group (F (1,80) 1⁄4 28.6, p < .0001). Among the unstable ones (in hippocampal predominant atrophy group at year one and not in the same group at year two), 32% go on to develop both hippocampal and cortical atrophy. Conclusions: Identifying the groups with persisting hippocampal predominant atrophy patterns in the predementia stages could help delineate the future clinical trajectories of clinical phenotypes very early in the disease course. This could have direct implications for diagnosis, patient counseling, management and design of clinical trials in AD.