Difference in Walking Performance by Types of Cognitive Task during Treadmill Walking

The purpose of this study was to identify effects of types of cognitive tasks during treadmill walking on SRV (stride rate variability). Experiments consisted of 5 conditions: (1) walking only, (2) walking with 2-back task, (3) 2-back task only, (4) walking with Stroop test, (5) Stroop test only. All experiments were performed with preferred walking speed for 10 minutes and 3D motion capture system (Motion analysis Corp., USA) with 6 cameras was used to collect kinematic data with sampling frequency of 120Hz. To compare each condition, temporal (stride interval time, swing interval time, stance interval time, step interval time, double support time) and spatial (stride length, step length, step width) variables were calculated from acquired data. CV (coefficient of variance) and DFA (detrended fluctuation analysis) were used to compare effects of types of cognitive tasks on stride-to-stride fluctuation. CV is used to describe the amount of variability and DFA the structure of variability. Results showed that types of cognitive tasks may influence stride-to-stride variability during treadmill walking. For CV, step length and step width variability were significantly different. For DFA, step time variability was significantly different. It may be helpful to identify relationship between cognitive function and gait mechanism through these kinds of dual task experiment. Further study is necessary to clarify this result.