100 Section - Neural correlates of cognitive-motor dual tasking: a systematic review of task-based fMRI studies

Objectives : Cognitive-motor dual-tasking (CMDT) is essential for daily activities but is often impaired in aging and neurological disorders (ND), thereby elevating fall risk. Functional magnetic resonance imaging (fMRI) provides whole-brain insights into the neural mechanisms underlying CMDT, yet systematic reviews remain limited. This review synthesizes evidence from task-based fMRI studies on CMDT in adults with and without ND, exploring the underlying mechanisms through comparisons of brain activation during dual- versus single-task (ST) conditions, population differences, and brain-behavior associations.

Design: This was a systematic review. Eight databases (MEDLINE, Embase, PsycINFO, PubMed, CINAHL, Cochrane Library, Web of Science, and Scopus) were searched, with a further search via Web of Science. The final search was completed on 07 April 2025. The protocol was registered in PROSPERO (CRD42024536737).

Results: Twenty four eligible articles were identified, including eight on participants with ND and 16 on healthy adults, comprising 106 ND patients (e.g., stroke, Parkinson's disease, and traumatic brain injury) and 544 healthy adults. Across populations, CMDT consistently produced poorer behavioral performance relative to ST conditions. Neurological groups often demonstrated widespread over-recruitment of executive and motor-related regions, with hyperactivation commonly associated with reduced performance, suggesting compensatory yet inefficient neural processing. Older adults showed varied activation patterns depending on cognitive demands, reflecting early over-recruitment followed by resource depletion, consistent with the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH). In contrast, healthy young adults exhibited flexible activation profiles modulated by task automaticity and demand, indicating preserved adaptability.

Conclusion: CMDT consistently challenges performance across populations, with distinct neural responses depending on age and neurological status. Current evidence does not identify a site-specific dual-task locus, as brain regions activated differ according to the nature of each task. Future research should incorporate standardized paradigms, larger samples, and broader ND representation to clarify mechanisms and inform interventions aimed at reducing fall risk and functional decline.