A systematic review and meta-analysis on the effect of virtual reality-based rehabilitation for people with Parkinson's disease.

Three of the 14 included studies were rated high risk of bias and eight raised some concerns, so the pooled estimates may be inflated. Several outcomes were based on very few studies: the 6-minute walk test on 3, the dynamic gait index on 5, and the freezing of gait questionnaire on 1, making those estimates unstable. Heterogeneity was substantial for the time up and go test (I-squared 75%), UPDRS II (I-squared 90%), and UPDRS III (I-squared 73%), meaning the studies disagreed about the size and direction of the effect. Blinding participants and therapists to the type of therapy is difficult in VR studies, which can inflate the apparent benefit. Most studies measured outcomes immediately after the intervention; long-term follow-up was limited, so it is unclear whether the balance gains are maintained. The VR interventions varied widely in equipment, session length, frequency, and duration, so it is hard to identify which features drive the effect.

Funded by the Korea Disease Control and Prevention Agency. No industry funding or author conflicts of interest are declared in the text.

Do not read the balance improvement as proof that VR is broadly superior to conventional therapy for Parkinson's. The primary gait outcomes (time up and go test, 6-minute walk) and all secondary outcomes (motor function, daily living, quality of life) showed no significant difference, and the one positive gait result (10-metre walk test) was based on only five small studies with a mean difference of 0.09.