Fluctuation of Stride Time Intervals During Walking with Smartphone

Gait cycle variability, characterized by a sequence of stride time intervals during steady-state walking, exhibits long-range correlated 1/f-like fluctuation in healthy young adults, which is known as gait fractality. Gait fractality tends to disappear in elderly individuals and patients with neurological diseases such as Parkinson's disease. Here, we examined influence of a cognitive load on the gait cycle variability. To this end, three walking conditions, including normal walking, walking with watching a smartphone with blank screen (non-cognitive task), and walking with playing a puzzle game of a smartphone (cognitive task). Stride interval variability was characterized by the mean, the standard deviation, and the degree of long-range correlation quantified by the scaling exponent estimated by the detrended fluctuation analysis. Although a number of acquired data at this moment is quite small necessary for concluding effects of the cognitive task, the scaling exponent tended to decrease during smartphone walking. Acquisition of more data to make this preliminary result confident is our future subject.