Frequency of cognitive impairment and depression in Parkinson's disease: A preliminary case-control study

BACKGROUND: This study aimed to determine the frequency of cognitive impairment and depression in our Parkinson's Disease (PD) and their relationship with disease severity and disability. PATIENTS AND METHODS: A total of 40 PD patients and 40 age-, sex-, and educationally matched controls were studied. The Unified Parkinson Disease Rating Scale (UPDRS) Motor and Activities of Daily Living (ADL) scores and the Hoehn and Yahr (HY) stage were documented. Depression was assessed using the Zung Self-Rating Depression Scale (ZSDS), while cognition was evaluated using a composite score of the mini-mental state examination (MMSE) score and category fluency score. RESULTS: A total of 55% (22/40) of PD and 10% (4 of 40) of controls had depression (P<0.001). A total of 60% of PD (24/40) and 5% of controls (2/40) had cognitive impairment (P<0.001). Both NMS coexisted in 16 of 40 PD (40%) compared with none of the controls (P<0.001). UPDRS (motor and ADL) scores and HY stage were significantly worse with impaired ZSDS scores - P 0.001. UPDRS ADL was significantly impaired by the presence of cognitive impairment. Coexisting depression and cognitive impairment were associated with significant worsening of all scores of severity and disability. CONCLUSION: Cognitive impairment and depression accompany our PD and are related to disability and worsening disease severity.