chapter  66
Pick’s disease: Its relationship to progressive aphasia, semantic dementia and frontotemporal dementia
ByJohn Hodges
Pages 12

Considerable advances continue to be made in our understanding of the group of neurodegenerative diseases that present itself with focal cognitive decits arising from circumscribed pathology of the frontal and/or temporal lobes, most commonly referred to collectively as Pick’s disease (PiD) or frontotemporal dementia (FTD). However, the literature on these conditions is lled with a confusing plethora of terms, which can make these developments dicult to follow for the non-expert. Central to this problem is a lack of clarity as to the intended level of description (clinical syndrome versus clinicopathological entity versus specic histological diagnosis) and a lack of concordance between these levels. For example, while some labels denote a clinical syndrome without specic histological implications (e.g. progressive aphasia, semantic dementia or dementia of frontal type), others denote specic neuropathological entities (e.g. PiD or familial tauopathy), hybrid clinicopathological entities (e.g. FTD) or even specic genetic disorders (e.g. FTD with parkinsonism linked to chromosome 17). Recent dierences in opinion over terminology are well illustrated by the titles of the following books, all published in the last decade: Pick’s Disease and Pick Complex (Kertesz and Munoz, 1998), Frontotemporal Dementia (Pasquier et al., 1996), Fronto-Temporal Lobar Degeneration: Fronto-Temporal Dementia, Progressive Aphasia, Semantic Dementia (Snowden et al., 1996) Frontotemporal Dementia Syndromes (Hodges, 2007). is lack of clarity is acknowledged and eorts to rationalize terminology and achieve clinicopathological and nosological consensus have been

made (Brun et al., 1994; Neary et al., 1998; McKhann et al., 2001; Kertesz et al., 2003b).