Early neuropsychological detection and the characteristics of Parkinson's disease associated with mild dementia.

Parkinson's disease (PD) may exhibit patterns of cognitive deficits, yet physicians are currently lacking operational criteria to define the clinical boundaries between PD and PD dementia (PDD). Therefore, we investigated the characteristics of the cognitive impairments in mild PDD. We recruited 30 PDD, 20 PD-MCI (PD with mild cognitive impairment without dementia) and 33 controls. All subjects were evaluated with detailed neuropsychological tests. Our results showed that visual memory, visuospatial functions, naming and calculation displayed more marked impairment than that of the other domains. Thus we suggest that adding cognitive dysfunctions of cortical type to the early cognitive deficits of PD-MCI can help predict the development of dementia.