Mild cognitive impairment in Parkinson's disease: Characterization and impact on quality of life according to subtype.

Aim Mild cognitive impairment (MCI) was initially described as a risk factor for Alzheimer's disease. Because of differences in baseline cognitive abilities, MCI in Parkinson's disease (PD; PD-MCI) requires distinct neuropsychological criteria for diagnosis and follow up. In addition to representing a risk factor for PD-related dementia, PD-MCI results in higher morbidity, which can be reduced through early detection. The aim of the present study was to gather data regarding MCI subtypes from neuropsychological profiles and clinical features in PD patients, to evaluate its impact on patients' quality of life according to subtype, and to compare the data with a control (Co) group. Method A total of 149 individuals were selected: 81 controls and 60 patients diagnosed with PD according to the United Kingdom Parkinson's Disease Society Brain Bank criteria. All individuals were submitted to neurological and neuropsychological assessments. Results The amnestic subtype of MCI was the most common in both the PD and Co groups. PD patients showed greater impairment in MCI than the Co group. The amnestic subtype of PD-MCI was associated with a lower quality of life compared with the non-amnestic group. Conclusions The PD group showed worse cognitive performance than the Co group. The amnestic subtype of PD-MCI was associated with the greatest impairment of quality of life. Geriatr Gerontol Int 2019; 19: 497-502.