Cognitive impairment in Parkinson's disease without dementia.

Some degree of cognitive impairment appears frequently in Parkinson's disease (PD) patients, even at the onset of the disease. However, due to the heterogeneity of the patients and the lack of standardized assessment batteries, it remains unclear which capacities are primarily affected by this disease. Fifty PD patients were assessed with 15 tests including executive functions, attention, temporal and spatial orientation, memory, and language tasks. Their results were compared with those of 42 age- and education-matched healthy seniors. Semantic fluency, along with visual search appeared to be the most discriminant tasks, followed by temporal orientation and face naming, as well as action naming and immediate recall. PD patients studied showed an impairment of frontal- to posterior-dependent capacities. Executive functions, attention, and recall tasks appeared to be significantly impaired in the patients. Nevertheless, significantly poor scores in tasks like action and face naming, as well as semantic fluency, also reveal a mainly semantic deficit.