Effects of Smile Training on Gait Disturbance in Parkinson’s Disease Patient with Neuropsychiatric Symptoms: A Single Case Design

Objective: To verify the efficacy of smile training in improving gait disturbances in patients with Parkinson’s disease (PD) exhibiting neuropsychiatric symptoms. Methods: A single-case BAB design with three intervention periods (B1, A1, and B2) was used. During periods B1 and B2, 10 min of smile training (facial muscles training and positive thinking training) was performed before the usual exercise therapy. During the A1 period, the participant received only the usual exercise therapy. During the intervention period, the Timed Up and Go test (TUG) was performed daily in both directions. Tau-U was calculated to determine the effect size of the TUG test time and the number of steps taken during each period. Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part III, Hospital Anxiety and Depression Scale (HADS), 10-meter walk at maximum speed, Berg Balance Scale, and Characterizing Freezing of Gait Questionnaire (C-FOGQ) were administered on the day before the start of the intervention and the last day of each period. Results: Comparisons of A1 to B2, TUG time, and the number of steps taken on both turns revealed large reductions (Tau-U ≥0.74, p