Abstract

In order to compare the progression of memory impairments in Parkinson's disease (PD) and Alzheimer's disease (AD), we administered the Memory and Information section of the Blessed Dementia Scale (BDS) at least twice to 33 patients with PD and 70 with AD. The BDS scores of AD patients deteriorated over time. In contrast, the scores of PD patients were essentially stationary. A substantial difference in rate of cognitive decline persisted upon comparing only those PD and AD patients who showed memory deficits of the same magnitude. The uniform failure to observe cognitive deterioration among PD patients suggests that any PD patients who deteriorate at a rate typical of AD may indeed have AD or a related dementing disorder in addition to the characteristic nigral-striatal degeneration of PD.