Clinical correlates of repetitive speech disorders in Parkinson's disease

Objectives: This study aimed to explore clinical correlates of repetitive speech disorders in patients with Parkinson's disease (PD). Methods: This study investigated speech function (Assessment of Motor Speech for Dysarthria and Stuttering Severity Instrument-3), motor function (Unified Parkinson's Disease Rating Scale III [UPDRS-III] and UPDRS-IV), cognitive function (Mini-Mental State Examination [MMSE], Montreal Cognitive Assessment [MoCA], Stroop color-word test, verbal fluency, digit span tests, and line orientation), and activities of daily living of 113 PD patients. Comparison between groups (independent t-tests, Mann Whitney U tests, or chi(2) test) and linear regression analyses were performed to determine clinical correlates of repetitive speech disorders. Results: Totally, 65 patients (57.5%) had repetitive speech disorders. Patients with repetitive speech disorders had significantly worse UPDRS-III (P = .049), MoCA (P = .030), and speech function and higher levodopa equivalent daily dose (LEDD; P = .031) than those without repetitive speech disorders. Males were significantly predominant in patients with repetitive speech disorders (64.6%) compared to those without repetitive speech disorders (18.7%; P < .001). The univariate and subsequent multiple linear regression analyses revealed that the severity of repetitive speech disorders significantly correlated with gender (P < .001), MoCA (P = .006), and speech variables (abnormal rate, P = .007; imprecise consonants, P = .043), independent from disease duration, UPDRS III, and LEDD. Conclusions: PD patients with repetitive speech disorders had worse motor, cognitive, and speech functions than those without repetitive speech disorders. The most influential factor for repetitive speech disorders might be male gender.