Remote memory in Parkinson's disease and senile dementia.

Remote memory for public events was investigated in 14 demented patients with Parkinson's disease (PD), 14 non-demented PD patients, and 14 controls. These groups were compared with 16 demented patients with dementia that was due to Alzheimer or was of vascular origin (SDAVT), and with a group of elderly controls. The two demented groups were of a different age but displayed a comparable degree of dementia. Remote memory was assessed using a 'famous events' questionnaire with items both of comparable salience and difficulty. Results showed severely impaired retrograde memory functions in the two demented groups for both recall and recognition with non-demented PD patients performing similar to the controls. Remote memory impairments extended 30-40 years without any temporal graded memory losses. Non-demented PD patients and controls showed an inferior free recall performance, especially for the remote past. The two PD groups benefited from recognition to the same extent as the controls, whereas the improvement for SDAVT patients was inferior when compared to their elderly controls. In contrast to SDAVT patients, anterograde memory was associated with remote memory for specific decades in demented PD patients. The results are interpreted with respect to an underlying retrieval deficit with a superimposed anterograde impairment common to both types of dementia and an additional loss of storage sites in SDAVT patients.