Clinical comparison of dementia in Parkinson's and Alzheimer's disease.

Neuropsychological, neuropathological and neurochemical findings show different types of dementias. Few of them have been able to confirm a division into "subcortical" and "cortical" dementia, so this concept has to be questioned. The present clinical study compared type and severity of dementia in 12 Parkinson-patients (PD) and 12 Alzheimer-patients (AD). The age-adjusted normal value differed a significantly from both patient groups. No significant difference in pattern of neuropsychological deficits between PD- and AD-patients was apparent. However, after similar duration of illness, dementia was more severe in AD- than in PD-patients.