Subcortical and deep cortical atrophy in frontotemporal lobar degeneration

Though neuroimaging, pathology and pathophysiology suggest a subcortical and deep cortical involvement in Frontotemporal Lobar Degeneration (FTLD), no studies have comprehensively assessed the associated gray matter (GM) volume changes. We measured caudate, putamen, thalamus, and amygdala GM volume using probabilistic a-priori regions of interest (ROIs) in 53 early FTLD patients (38 behavioral variant FTD [bvFTD], 9 Semantic Dementia [SD], 6 Progressive Non-Fluent Aphasia [PNFA]), and 25 age-matched healthy controls (HC). ANOVA showed significant (P<0.001) main effect of diagnosis, and significant interactions for diagnosis and region, and diagnosis and hemisphere. Post-hoc comparisons with HC showed bilateral GM atrophy in the caudate, putamen and thalamus, in bvFTD; a left-confined GM reduction in the amygdala in SD; and bilateral GM atrophy in the caudate and thalamus, and left-sided GM reduction in the putamen and amygdala in PNFA. Correlation analyses suggested an association between GM volumes and language, psychomotor speed and behavioral disturbances. This study showed a widespread involvement of subcortical and deep cortical GM in early FTLD with patterns specific for clinical entity.