Clinical and pathological overlap between frontotemporal dementia, primary progressive aphasia and corticobasal degeneration: the Pick complex.

A substantive overlap between the clinical syndromes of frontal lobe dementia (FLD), frontotemporal dementia (FTD), or primary progressive aphasia (PPA), and corticobasal degeneration syndrome (CBDS) has been demonstrated in a population of 55 patients followed for more than 3 years in a cognitive neurology clinic. Patients presenting with the personality behavior disorder (FLD) often develop progressive aphasia (PA) and vice versa. CBDS is often associated with FLD and PA, and the extrapyramidal-apractic syndrome of CBDS often appears in FLD and PPA. The histopathological variations do not predict the clinical phenotype. The term Pick complex is suggested to indicate that these clinical and pathological variations are related and they were first described by Pick as clinical manifestations of fronotemporal atrophy. This term will avoid the confusion of using FLD or FTD or for the whole complex and also for the personality behavioral presentation. The relationship of the various clinical presentations has been strengthened by the discovery of chromosome 17 linkage in families manifesting them.