Immediate repetition does not reduce dual-task gait costs in Parkinson’s disease

Abstract

Background: Parkinson’s Disease (PD) is a neurodegenerative condition characterized by motor and cognitive impairments that compromise gait automaticity in dual-task (DT) situations. One of the main manifestations of PD is gait disturbance, one of the most disabling motor symptoms, including difficulty performing gait phases and postural instability. Within this context, there is direct interaction with cognitive alterations, particularly executive functions, memory and attention. Under these conditions, motor and cognitive costs increase, reflecting greater dependence on attentional resources, functional decline, increased risk of falls, and impact on quality of life. It remains unclear whether the immediate repetition of gait under DT conditions promotes motor learning and reduces these costs in individuals with PD. Objective: To investigate whether motor and cognitive costs of gait under DT conditions decrease across ten consecutive trials in individuals with PD, examining presence or absence of immediate motor and cognitive adaptation. Methods: This was a cross-sectional observational study including 49 individuals with PD and a mean age of 61.1 ± 9.7 years, in stages 1 to 3 of the Hoehn and Yahr Scale (H&Y), with independent gait and no cognitive impairment. Exclusion criteria were: (1) other neurological conditions; (2) uncorrected visual or hearing impairments. Participants were assessed in a single session by trained physiotherapists, during the ON medication state. Clinical assessment included the Unified Parkinson’s Disease Rating Scale (UPDRS) to evaluate motor severity and the Montreal Cognitive Assessment (MoCA) to assess cognitive performance. Gait performance was evaluated using the GAITRite system, a unidimensional pressure-sensitive walkway that measures spatiotemporal gait parameters. Participants were assessed under three different conditions presented in random order: (1) single motor task (walking only); (2) single cognitive task (verbal fluency); and (3) dual task (walking while evoking words simultaneously). Each condition was repeated for ten consecutive trials. Motor and cognitive costs were calculated based on spatiotemporal gait parameters. Results: No significant differences were observed between DT gait costs calculated from three versus ten consecutive trials across any analyzed parameters (p > 0.05). Overall, the results indicate that using three trials is sufficient to robustly estimate gait cost in individuals with PD, even after controlling for age, disease severity and cognitive performance. Conclusion: The results indicate no evidence of reduction in motor and cognitive costs of gait under DT conditions across ten consecutive trials, even in early stages of the disease. This suggests that deficits in automaticity and attentional resource allocation in PD do not improve through immediate repetition but rather require structured motor and cognitive training interventions.