Impact of dual-tasking and balance confidence on turns and transitions: a cross-sectional study in Parkinson’s disease

BACKGROUND: Mobility, cognitive processing, and balance confidence impairments can negatively affect functional mobility in people with Parkinson's disease (PD). This study aimed to examine the effects of a cognitive dual-task on functional mobility during Timed Up and Go (TUG) sub-phases involving transitions and turns. A secondary aim was to explore whether balance confidence was associated with dual-task interference (DTI) on TUG total duration and sub-phases. METHODS: A cross-sectional design was employed. Participants completed TUG and TUG-COG (serial three subtractions) and inertial sensors recorded spatiotemporal data on transitions and turns. Paired samples t-tests and corresponding effect sizes (Cohen's d) were used to compare TUG conditions. Multivariate linear regression assessed the association between balance confidence and DTI on total duration and sub-phases, controlling for gait speed and executive function. RESULTS: People with mild-to-moderate PD (N = 94, mean age: 68.7 years) completed TUG-COG 2.7 s slower than TUG (p < 0.001, d = 0.5, DTI = 22.9%). The cognitive task led to reduced performance across TUG sub-phases, with generally stronger effects observed in turning outcomes (d = 0.25-0.45) and comparatively smaller effects observed in postural transitions (d = 0.02-0.38). Balance confidence explained variance in DTI for sit-to-stand duration (B = --3.560, 95% CI [-5.499, -1.622], p < 0.001), whereas no effect was observed for other sub-phases. CONCLUSION: Dual-tasking impaired nearly all components of the TUG, prolonging total duration and altering spatiotemporal characteristics of transitions and turns. Turning was more strongly impacted by dual-tasking than postural transitions, which has relevance for fall-prevention strategies. Together, the results of this study indicate that clinicians should prioritize turning during dual-task gait training and incorporate assessment of balance confidence to better capture functional capacity in transitional movements such as sit-to-stand.