Author(s): PATERNO, A., LIBERALI, G., PRIVITERA, M., DAL MORO, P., MODUGNO, N., FEDERICO, B., CORREALE, L., PEYRÉ-TARTARUGA, L.A., Institution: UNIVERSITÀ DI CASSINO E DEL LAZIO MERIDIONALE, Country: ITALY, Abstract-ID: 637

INTRODUCTION:
Parkinson's disease (PD) is characterized by motor and cognitive deficits that become markedly evident during dual-task (DT) walking, where a secondary cognitive or motor task is performed simultaneously. While spatiotemporal gait alterations under DT are well-documented, a comprehensive synthesis of the underlying biomechanical and neurophysiological changes is lacking. This systematic review aimed to characterize the biomechanical gait alterations under DT conditions in individuals with PD, identify associated neurophysiological correlates, and evaluate the methodological quality of the existing evidence.
METHODS:
A systematic literature search was conducted across five databases (PubMed, Scopus, Web of Science, Cochrane Library, EBSCO) from 2000 to 2025, following PRISMA guidelines. Forty-four studies meeting the PECOS inclusion criteria were included. Studies involved PD patients in the “ON” medication state during DT walking, compared to healthy controls. Methodological quality was assessed using the AXIS tool and a customized DT-checklist, and the review protocol was registered in PROSPERO (CRD420251004404). Meta-analyses, meta-regressions, and subgroup analyses examining the effects of disease severity, DT type, and walking modality are currently in progress.
RESULTS:
Preliminary synthesis indicates that DT consistently exacerbates gait impairments in PD, with reductions in stride length (10–20%), gait speed (15–30%), and knee joint range of motion (5–12°), alongside increased stride time variability (20–40%). Cognitive DTs, such as Stroop or serial subtraction tasks, induced greater deterioration than motor DTs, particularly in individuals with the Postural Instability/Gait Difficulty phenotype (+35% step variability) and those experiencing freezing of gait (−28% speed). Overground walking imposed greater DT costs (−22% speed) than treadmill walking, and motion capture systems were more sensitive than walkway-based measures in detecting kinematic alterations. Neurophysiological studies using fNIRS revealed compensatory hyperactivation of the prefrontal cortex, suggesting a shift from automatic to controlled movement. External cueing and dopaminergic medication partially mitigated DT-related deficits.
CONCLUSION:
DT walking in PD is characterized by shortened strides, slowed gait, increased variability, and a stiffened gait pattern, driven by heightened cognitive control and compensatory prefrontal activation. These preliminary findings highlight the potential of DT assessment as a functional biomarker and underscore the need for standardized protocols and integration of cognitive load measures to guide precision rehabilitation. Ongoing meta-analyses and subgroup investigations will provide further quantitative confirmation of these effects.