Abstract

Corticobasal degeneration (CBD), Pick's disease (PiD) and progressive supranuclear palsy (PSP) are the most common tauopathies after Alzheimer's disease. The traditional view of CBD and PSP as movement disorders and PiD as a dementia is changing, but the balance of cognitive and motor features in these conditions remains controversial. We therefore conducted a systematic review of the literature, searching PubMed and EMBASE for all English-language reports of clinical data in autopsy-confirmed cases. A weighted average frequency across studies was calculated for each feature. As expected, parkinsonism, postural instability and gait disturbance were seen in a majority of cases of both CBD and PSP, but this was also true of motor speech disorder, supranuclear gaze palsy and depression. Many features were seen in both but more commonly in CBD, including apraxia, aphasia and behavioural disturbance as well as dystonia, tremor, myoclonus and pyramidal signs. PiD was usually—though not universally—associated with behavioural and executive impairments, and sometimes with aphasia and motor speech disorder, but parkinsonism, postural instability and pyramidal signs were each observed in a significant proportion of cases. Very few features were unique to any one of the three conditions. Quantitation of the frequency of clinical features in degenerative diseases is problematic and new approaches are needed.