[Cortico-basal degeneration]

Corticobasal degeneration (CBD) is not rare disease, because in our clinic 13 patients were observed for the past 8 years, with ratio to those with Parkinson's disease being 1:18. Our clinical criteria of this disease consist of the combination of 1) limb-kinetic apraxia as cortical sign, 2) akinetic-rigid sign as extrapyramidal sign, 3) their marked asymmetry, and as additional findings, 4) the presence of grasp reflex, alien hand sign, reflex myoclonus, limb dystonia, and others, and 5) neuroimagings (MRI, SPECT) suggestive of asymmetric cortical lesions. There are reports indicating that clinical CBD was diagnosed as Pick's disease, progressive supranuclear palsy and Alzheimer's disease, pathologically. Therefore, more basic investigations, especially from molecular biology are necessary to discriminate these corticobasal complex disorders.