Effect of Dual-task Exercise on Cognition and Dual-task Cost in the Elderly with Mild Cognitive Impairment: A Randomized Pilot Study

Introduction: Dual-task (DT) training may enhance cognition and function in older adults with mild cognitive impairment (MCI). Whether virtual reality (VR)-based DT exercise offers advantages over traditional strength-based DT training remains unclear. This study compared their effects on cognition and dual-task cost (DTC) in elderly adults from Montes Claros, Brazil. Methods: Twenty independent seniors were randomized to VR-based DT training with Nintendo Wii (n=11) or traditional DT strength exercises (n=9), twice weekly for 26 sessions. Outcomes included global cognition (MoCA), memory (Digit Span), verbal fluency, and DTC (Timed Up and Go + verbal fluency). Results: Post-intervention analysis revealed distinct effects between training modalities. Participants in the DT group demonstrated significant improvements in working memory (p=0.02), particularly among individuals without MCI, who improved by an average of 1.66 points on the Digit Span backward test. In contrast, those in the VR group experienced a decrease in working memory performance. However, the VR group showed a significant reduction in DTC, with a 9.92% improvement in task execution time (p=0.01), irrespective of MCI status. Meanwhile, the DT exercise group exhibited a 7.06% increase in DTC, suggesting a potential trade-off between cognitive and functional gains depending on the type of dual-task intervention. discussion: These results suggest a trade-off between cognitive and motor-cognitive benefits depending on the training modality. The DTE program may enhance executive function, particularly working memory, in non-MCI individuals, possibly due to more targeted cognitive engagement. Meanwhile, the VRE program, with its integrated motor-cognitive demands, appears to improve functional adaptability by reducing DTC, potentially offering advantages for daily task performance in older adults regardless of cognitive status. Discussion: Findings suggest a trade-off: traditional DT training may preferentially benefit cognition, while VR-based DT training may improve task efficiency by lowering DTC. Conclusion: Traditional DT exercise appears more effective for working memory, particularly in non-MCI elderly, whereas VR-based DT exercise may better support dual-task performance.