Dual‐Task Gait Cognitive‐Motor Interference as a Marker of Cognitive Impairment in Parkinson's Disease: A Systematic Review and Meta‐Analysis

Abstract Background Cognitive impairment in Parkinson's disease (PD‐CI) negatively affects mobility, independence, and quality of life. Dual‐task (DT) gait testing, which captures cognitive–motor interference (CMI), has emerged as a promising, non‐invasive method to detect PD‐CI. Objective This systematic review and meta‐analysis assessed the sensitivity of DT gait parameters—including stride length, gait speed, cadence, variability, and Timed Up and Go (TUG)—in differentiating PD‐CI from cognitively normal PD (PD‐NC), and examined subgroup differences between mild cognitive impairment (PD‐MCI) and subjective cognitive decline (PD‐SCD). Methods PubMed, Web of Science, and Embase were searched for observational studies comparing DT gait in PD‐CI versus PD‐NC. Random‐effects meta‐analyses estimated pooled effect sizes (Hedges’ g ), with subgroup and meta‐regression analyses exploring task‐ and disease‐related moderators. Results DT stride length showed the largest impairment in PD‐CI ( g = −0.994, P < 0.001), followed by TUG ( g = +0.850, P = 0.001), gait speed ( g = −0.542, P = 0.001), cadence ( g = −0.370, P = 0.002), and stride variability ( g = +0.590, P < 0.001). Subgroup analyses indicated DT gait speed reliably differentiated PD‐MCI from PD‐NC ( g = −0.59, P < 0.001), but not PD‐SCI from other groups. Meta‐regression showed shorter disease duration (≤5 years) and lower Hoehn & Yahr stage (<2) predicted larger DT impairments ( P < 0.01), while age and sample size were non‐significant. Conclusion DT gait parameters—especially stride length, gait speed, and TUG—are sensitive markers of PD‐CI, with greatest utility at the PD‐MCI stage. Standardized protocols and longitudinal validation are warranted.