Cognitive Function and Quality of Life in Parkinson's Disease: A Cross-Sectional Study.

BACKGROUND Parkinson's disease with mild cognitive impairment (PD-MCI) or dementia (PDD) has been shown to be correlated with poor quality of life (QoL). The association between specific cognitive domains and QoL is less clear. OBJECTIVE To determine how the cognitive domains affect QoL in different cognitive states in PD. METHODS We recruited 600 PD patients, including 185 PD patients with normal cognition (PD-NC), 336 PD-MCI patients, and 79 PDD patients. All patients underwent a scale-based assessment (PDQ-39) for QoL, as well as clinical evaluations and neuropsychological tests. RESULTS Compared to PD-NC group, QoL became more impaired in the PD-MCI and PDD groups. Generalized linear model revealed that no neuropsychological test was significantly associated with QoL in PD-NC group; neuropsychological tests in attention and language domains were significantly associated with QoL in PD-MCI patients; neuropsychological tests in memory and language domains were significantly associated with QoL in PDD patients. CONCLUSIONS Cognitive domains contribute differently to QoL in PD. These findings may prompt clinicians to target specific cognitive domains for improving QoL in the PD patients.