Efficacy of repeated external cueing training on freezing of gait and gait performance in Parkinson's disease: a systematic review and meta-analysis.

Background: Freezing of gait (FOG) is a disabling gait disturbance in Parkinson's disease (PD) that responds poorly to pharmacological treatment. External cueing has been proposed as a non-pharmacological strategy to improve gait and mobility; however, the effectiveness of repeated external cueing training on FOG-related outcomes remains uncertain, particularly across different cueing modalities. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), with a specific focus on repeated external cueing interventions (≥2 weeks). PubMed, Web of Science, Embase, the Cochrane Library, CNKI, Wanfang, and VIP databases were searched from inception to November 10, 2025. RCTs evaluating external cueing interventions in individuals with PD were included. Primary outcomes were FOG severity assessed by the Freezing of Gait Questionnaire (FOGQ) or New FOGQ (NFOGQ). Secondary outcomes included Timed Up and Go (TUG), MDS-UPDRS part III, and Berg Balance Scale (BBS). Risk of bias was assessed using ROB 2.0, and evidence certainty using GRADE. Results: Nine RCTs involving patients with PD were included. Pooled analysis showed no statistically significant reduction in FOG severity following external cueing interventions compared with control conditions (SMD = -0.30, 95% CI: -0.68 to 0.09), with substantial heterogeneity. In contrast, external cueing significantly improved functional mobility as measured by the TUG test (SMD = -0.65, 95% CI: -1.15 to -0.15), although heterogeneity remained high. No consistent benefits were observed for overall motor symptoms or balance outcomes. Exploratory analysis incorporating short-term follow-up data suggested a modest improvement in FOG severity; however, these findings should be interpreted with caution due to persistent heterogeneity. The certainty of evidence for all outcomes was rated as low according to the GRADE framework. The observed heterogeneity was likely attributable to variations in intervention protocols, cueing modalities, and outcome assessment methods. Conclusion: External cueing interventions may improve functional mobility in individuals with PD, particularly for tasks involving gait initiation and turning. However, current evidence does not support consistent benefits for FOG severity, overall motor symptoms, or balance. Given the low certainty of evidence, further high-quality, multicenter RCTs with standardized outcome measures and longer follow-up are needed to clarify the clinical role of cueing-based interventions in FOG. These findings highlight important limitations in the current evidence base and provide directions for future research. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261280910, identifier CRD420261280910.