The effect of exercise interventions on executive function in individuals with Parkinson's disease

Objective: Given the uncertainty surrounding the most effective exercise prescription variables (frequency, intensity, type, duration) and the impact of Parkinson's disease (PD) characteristics (illness duration, age, severity, baseline cognitive status, levodopa dosage) on different subdomains of executive function (EF) improvement, we conducted a systematic review and meta-analysis with moderator analysis to assess these effects. Method: Six electronic databases (Embase, PubMed, MEDLINE, Academic Search Complete, CINAHL, AGELINE) were searched by two independent authors. Clinical trials published before April 2024 that reported the effect of chronic exercise on EF in individuals with PD were included. Results: Of 608 identified studies, 18 studies met eligibility criteria. The overall effect size (ES) of exercise on EF was small but positive and significant (ES= 0.21, p < .001). Among EF subdomains, cognitive flexibility showed significant improvement. Regarding exercise prescription, larger ES were observed for high (≥2 per week) frequency, moderate to vigorous intensity, mind-body exercise, and 45–60 min for each session. Sample characteristics such as older age, high levodopa equivalent daily dosage (LEDD) (≥600 mg/day), and baseline cognitive impairment were found to attenuate the effect of exercise on EF. Conclusion: Exercise is a promising non-pharmacological intervention for enhancing EF in PD, particularly improving cognitive flexibility. Mind-body exercises appear particularly effective. Recommended programs should be moderate to vigorous in intensity, lasting 45–60 min, and conducted at least twice weekly for 13–16 weeks. The benefits of exercise diminish with age and with LEDD exceeding 600 mg/day. Additionally, PD patients with cognitive impairments may experience reduced benefits. Early exercise engagement is recommended, while disease severity and duration have minimal impact.