Insole-Derived Plantar Pressure Variability Reveals Dual-Task Gait Differences in Early-Stage Parkinson's Disease

Abstract

Objective: Gait disturbances in Parkinson's disease (PD) indicate impaired motor automaticity, particularly under cognitively demanding conditions. Although spatiotemporal parameters are commonly used to assess dual-task cost (DTC), their sensitivity in PD is limited. This study aimed to characterize the plantar pressure alterations during dual-task walking using a sensor-based insole system and compare them with conventional gait metrics. Method: We performed an on-site validation of the insole-derived parameters against a 3D motion analysis system in healthy adults. Subsequently, we conducted a cross-sectional study comparing spatiotemporal parameters, plantar pressure metrics, and DTCs among healthy young adults, healthy older adults, and patients with early-stage PD (EPD). Participants completed 10-meter walking tests under both single- and dual-task (serial subtraction) conditions. Results: The insole-derived parameters showed significant agreement with the 3D motion analysis, with cadence and acceleration times demonstrating good validity. Under single-task conditions, patients with EPD exhibited slower velocity, shorter stride length, and greater gait variability than both control groups. Plantar pressure analysis revealed reduced peak pressures in the toe, medial forefoot, and heel regions in patients with EPD, with increased variability particularly in the heel region. Under dual-task conditions, spatiotemporal DTCs did not differ significantly between the groups. In contrast, plantar pressure metrics revealed distinct alterations in patients with EPD, with reduced heel loading and increased variability. Conclusion: These findings suggest that plantar pressure metrics provide additional sensitivity beyond conventional spatiotemporal parameters for detecting dual-task-related gait alterations in patients with PD, highlighting their potential utility in clinical assessments. Clinical Impact-Affordable, easy-to-use sensor-based insoles provide practical and sensitive gait metrics, enabling detection of subtle gait changes and helping bridge the gap between research-grade gait analysis and routine clinical practice.