PSP-FTD Complex: A Possible Variant of PSP.

This study tried to find out type of lobar features found in patients with progressive supranuclear palsy (PSP) and whether they differ from those of frontotemporal dementia (FTD) as both of these are tauopathies. We studied lobar functions of 45 patients with PSP. Five (11.1%) patients had no lobar feature; 11 (24.4%) had PSP-like features like apathy, frontal release signs, impaired motor Luria written sequences, and fist-edge-palm test; and 29 (64.4%) patients had FTD-like lobar features like disinhibition, poor naming, and word finding difficulty. Among features resembling FTD, behavioural variant type occurred in 31.1%, primary progressive aphasia type occurred in 58.6%, 3.4% patients had semantic dementia type features, and 6.9% were unclassified. Hence, patients with PSP with lobar features may fall in the middle of PSP-FTD spectrum with frontal lobe features typical of PSP (PSP-frontal like) and those with frontal lobe features resembling FTD (PSP-FTD complex) in between.