Gait asymmetry in Parkinson's disease - a systematic review and meta-analysis (AsymmGait-Parkinson study)

Gait asymmetry (GA) in people with Parkinson’s disease (pwPD) has been inconsistently reported, leading to uncertainty about its prevalence and clinical significance. GA may relate to motor symptoms’ lateralization and the effects of dopaminergic medication. The aim of this study was to systematically summarize the current literature and perform a meta-analysis to investigate the differences between GA in pwPD compared to healthy individuals and to evaluate the effect of dopaminergic medication on GA. The review was registered in PROSPERO database (ID: CRD42021285067). The searching was conducted in the PubMed, Cochrane Library, Lilacs, PEDro and Scopus databases. The primary search resulted in 551 studies. After removing the duplicates, 451 studies remained for the analysis. After checking the full text, 42 studies with 2111 pwPD were included in this review. The meta-analysis showed that pwPD exhibited greater asymmetry in step length, step time, and swing time, particularly in the OFF state, with moderate effect sizes. Dopaminergic medication was associated with reduced swing time asymmetry. Temporal aspects of GA, particularly swing time asymmetry, was most sensitive to detect differences in GA between pwPD and healthy controls and to indicate an effect of dopaminergic medication. The inconsistent findings across studies highlight the need for standardization in GA measurement. Understanding the neural mechanisms underlying GA may improve targeted therapies. Further research should explore GA in more challenging walking conditions and in free-living environments to enhance the clinical understanding of gait disturbances in PD.