P2‐199: Neuropsychological Tests and Mild Cognitive Impairment Subtypes Associated with Development of Dementia in Non‐Demented Patients with Parkinson's Disease

Dementia is a key symptom of Parkinson's disease (PD), and influences the patient's quality of life and the caregiver's burden. This study aimed to identify neuropsychological tests and mild cognitive impairment (MCI) subtypes that show strong association with conversion from non-demented PD and PD-MCI to dementia with Parkinson's disease (PDD). Non-demented PD patients who had undergone comprehensive neuropsychological tests at baseline were included in this study. We compared the data between individuals who converted to PDD from the whole cohort, as well as from those with PD-MCI, with that of non-converters, and analyzed risk factors for PDD. In total, 390 patients with PD were included, and 47 patients had converted to PDD over a mean follow-up period of 6.4 years. Old age and the presence of MCI were the most significant clinical risk factors for conversion to PDD. In neuropsychological tests, converters showed more deficits in baseline language, visuospatial, and memory measures than non-converters. At baseline, 161 patients had been diagnosed with PD-MCI; they were older, had an older age at onset, higher Hoehn and Yahr stage, and lower Mini-Mental State Examination score and education level than cognitively healthy patients with PD. Among the PD-MCI patients, 30 had converted to PDD and converters showed more deficits than non-converters only in visuospatial function. Patients with multi-domain MCI converted to PDD more often than patients with single-domain MCI. Dysfunctions in the language, visuospatial, and memory domains were associated with conversion from non-demented PD to PDD in the total cohort of patients. In PD-MCI patients, only visuospatial dysfunction was related to conversion to PDD. Therefore, tests based on posterior cortical function may be more relevant to conversion to dementia in PD patients.