Author(s): SHIMIZU, S., OGURA, M., SAKAMOTO, M., Institution: KITASATO UNIVERSITY, Country: JAPAN, Abstract-ID: 1497

INTRODUCTION:
The dual task, including walking and cognitive activity, is used for predicting and assessing fall risk and training to improve cognitive and physical function in the elderly. In contrast, walking speed and cognitive task performance while performing dual tasks are reduced compared with those during the single task. This reduction is defined as dual-task interference. The influence is less on treadmill walking than on overground walking. The prefrontal cortex (PFC) activation during treadmill walking is higher than that during overground walking; however, PFC activity during dual tasking (walking and cognitive activity) is not known. This study compared PFC activation during treadmill walking and overground walking while performing cognitive tasks. This study aimed to investigate the effect of treadmill walking on PFC activation and dual-task performance in younger adults.
METHODS:
This randomized crossover study included 10 healthy young adults (mean 21.3 ± 0.6 years, 7 males) and compared overground and treadmill walking under dual tasking. Each participant walked while subtracting on the overground and treadmill. The participant walked thrice for 60 s at a comfortable walking speed in both conditions. The subtraction task used during walking was to consecutively subtract 7 from a three-digit number. PFC activation was assessed as oxyhemoglobin (O2Hb) responses using a wearable functional near-infrared spectroscopy. O2Hb levels in each condition were calculated as the difference from the resting standing condition and used for analysis. Walking speed, stride length, and stride variation were measured as walking functions, and the number and percentage of correct subtraction responses were calculated as cognitive functions. Walking functions were measured using a treadmill (Gait Training System BDX-GTM; Biodex) and a gait analyzer (Walk Way MW 1000; Anima). Differences in O2Hb, walking speed, stride length, stride variation, and the number and percentage of correct responses between the overground and treadmill conditions were evaluated.
RESULTS:
The number and percentage of correct responses were performed significantly better on treadmill. Variation in stride length was significantly higher during walking on the treadmill. There were no significant differences in walking speed and stride length between the two conditions. The O2Hb levels of PFC were significantly higher in the treadmill condition. O2Hb was significantly increased in the left PFC than in the right PFC under both conditions.
CONCLUSION:
Treadmill walking with cognitive activity increased cerebral blood flow in the dorsolateral PFC and improved cognitive task performance compared with those during overground walking.