Neurocognitive and atrophic patterns in Parkinson’s disease based on subjective memory complaints

Ample evidence has suggested that individuals with subjective memory complaints are at a higher risk for cognitive decline. Nevertheless, the significance of subjective memory complaints in Parkinson’s disease has not been studied until now. We investigated whether the patterns of cognitive profiles and gray matter density differed in cognitively normal patients with Parkinson’s disease based on the presence of subjective memory complaints. Using a single question with a yes or no answer, cognitively normal patients with Parkinson’s disease were classified as with (n = 20) or without subjective memory complaints (n = 15). Cognitive profiles and gray matter density were examined using standardized neuropsychological tests and voxel-based morphometry. No significant differences in demographic characteristics were observed between groups. The detailed neuropsychological tests demonstrated that Parkinson’s disease patients with subjective memory complaints had significantly decreased verbal fluency and slightly lower scores on the backward digit-span test compared with those without subjective memory complaints. A voxel-based morphometry analysis revealed that Parkinson’s disease patients with subjective memory complaints had significantly decreased gray matter density in the anterior cingulate gyrus and right inferior parietal lobule compared with those without subjective memory complaints. Our data demonstrated that Parkinson’s disease patients with subjective memory complaints showed a poorer performance on tasks related to verbal fluency and attention with more severe cortical atrophy compared to those without subjective memory complaints, suggesting that subjective memory complaints in patients with Parkinson’s disease may represent an early manifestation of underlying Parkinson’s disease-related pathological changes.