Cognitive and motor function in patients with Parkinson's disease with and without depression

The objective of this study was to define risk factors for depression in patients with idiopathic Parkinson's disease (PD) and to evaluate the correlation of depression with cognitive function and the primary domains of parkinsonian motor dysfunction tremor, bradykinesia, rigidity, gait and balance impairment. The risk factors for depression in patients with PD remain controversial. Several investigators have demonstrated a significant association between cognitive dysfunction and depression, but motoric and disease variables can confound this evaluation and have shown an inconsistent relation to depression. A consecutive series of 88 patients with PD were examined using the motor subscale of the Unified Parkinson's Disease Rating Scale (UPDRSm), Hoehn-Yahr stage (HY), and Hamilton Rating Scale for Depression (HRSD). Major depression was diagnosed according to the criteria in the Diagnostic and Statistic Manual of Mental Disorders, 4th edition. Gender, age, handedness, PD duration, side of PD onset, motor fluctuations, UPDRSm total score, daily Levodopa dose, and Mini-Mental State Examination score (MMSE) were analyzed using multivariate and univariate logistic regression, Fisher's Exact test, and Pearson correlations. Major depression was diagnosed in 12 patients (7.3%). Low MMSE score, axial bradykinesia, gait and balance impairment were strongly significant predictors of depression. In conclusion, depression and physical function are important factors impairing the quality of life for patients with PD, and regular depression screening and treatment should focus on patients with PD who have cognitive impairment, high axial bradykinesia, gait and balance impairment.