Staging disease severity in movement disorder tauopathies: brain atrophy separates progressive supranuclear palsy from corticobasal degeneration.

The movement disorders progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) both deposit tau in degenerating neurons and are considered to be tauopathies. The recently developed scheme for staging tissue degeneration in another tauopathy, frontotemporal dementia [Broe et al., Neurology 2003;60:1005-1011] was applied to pathologically confirmed PSP (n = 24) and CBD (n = 9) cases and correlated with clinical indices. In contrast to frontotemporal dementia, the majority of PSP cases had limited or no visible atrophy, while the pattern of atrophy in CBD cases conformed to the existing staging scheme (all but one case exhibiting substantial visible tissue atrophy). Despite similar clinical severity and disease duration between groups, there was a marked difference between the PSP and CBD cases in pathological disease stage (chi(2) = 8.86; P = 0.03). The degree of global atrophy in PSP appears to be distinct from other tauopathies, while CBD fits the same pattern as other pathological forms of frontotemporal dementia.