Stanley J Winser, Mohammad Jobair Khan, Abu Jor, Priya Kannan
To evaluate the (1) effectiveness of dual-task (DT) exercise in improving dynamic balance, motor function, functional mobility, dual-tasking, and falls, and (2) influence of DT intervention parameters on treatment effects in individuals with Parkinson's disease (PD). A comprehensive literature search was conducted across 12 electronic databases to identify relevant published articles from inception to September 2025. Risk of bias, methodological rigour, and evidence quality were evaluated using the RoB-2, PEDro, and GRADE tools, respectively. Dynamic balance, motor function, functional mobility, dual-tasking, and falls were assessed. Meta-analysis was performed to estimate intervention effects, and meta-regression evaluated how parameters of DT intervention affected treatment effects. The meta-analysis included 25 studies involving 1,162 individuals with PD. The mean PEDro score was 6.5, RoB-2 indicated a low risk of bias in 11 studies (45%), and GRADE indicated low to high evidence quality. Meta-analysis revealed significant improvements in dynamic balance (mean difference [MD]=4.45, 95% confidence interval [CI]=2.06 to 6.84; p<0.001), motor function (MD=-2.00, 95% CI=-3.32 to -0.67; p<0.001), functional mobility (MD=-1.64, 95% CI=-2.01 to -1.26; p<0.001), and dual-tasking (MD=-3.39, 95% CI=-4.67 to -2.11; p<0.001). Meta-regression revealed that dynamic balance improved with moderately challenging and moderate-intensity DT exercises, practised for 2 hours weekly with ≥90% session adherence. Subgroup meta-analyses revealed that practising for more than 4 weeks significantly improved dynamic balance and functional mobility. Compared with traditional single-task exercises, motor-cognitive DT exercises improved dynamic balance, functional mobility, motor function, and dual-tasking. Further studies examining the effects of DT exercises on falls among individuals with PD are warranted.