Treadmill Walking Maintains Dual-Task Gait Performance and Reduces Medial Prefrontal Cortex Activation in Healthy Adults

Abstract

Studies examining the motor-cognitive costs of dual-task gait have used varying conditions such as overground or treadmill walking, however it is not known whether brain activation patterns differ during these conditions. This study compared oxyhaemoglobin (O2 Hb) responses of the prefrontal cortex (PFC) during overground and treadmill walking. A total of 30 participants (14M/16F) were recruited in a randomized crossover study comparing overground and treadmill walking under single- and dual-task (STG and DTG) conditions. The DTG consisted of performing walking and cognitive (serial 7’s) tasks concurrently. A portable 24-channel functional near-infrared spectroscopy (fNIRS) system was placed over the prefrontal cortex (PFC), corresponding the left and right dorsolateral and medial PFC (DLPFC and mPFC) during overground and treadmill STG and DTG. Results showed a reduction in gait speed and distance during overground DTG compared to STG (P<0.001), but no differences between overground and treadmill conditions. During treadmill walking, gait speed, distance, and cognitive performances were maintained in both STG and DTG conditions. fNIRS results further indicated a reduction (P<0.05) in O2 Hb within the mPFC during treadmill compared to overground walking. However, no differences were observed in the left and right DLPFC between walking conditions. Our results support increased gait automation during treadmill walking, indicated by the lack of change in STG and DTG cognitive and gait performance, which was concomitant with a reduction in mPFC activation. These findings suggest different neural strategies underpinning treadmill and overground walking, which can be considered when designing gait training and rehabilitation interventions.

Funding Information: The authors would like to thank all participants in this study. Ms Jessie Leuk is supported by an NTU Research Scholarship.

Declaration of Interests: The authors declare no conflicts of interest for this study.

Ethics: This study was conducted in accordance to the Declaration of Helsinki, and all participants provided written informed consent before they could take part in this study. This study was approved by the NTU Institutional Review Board (IRB-2021-160).

Keywords: Gait, Single tasking, Dual tasking, Neuroimaging, Cognition