Gait Analysis: Head Vertical Movement Leads to Lower Limb Joint Angle Movements

Supported by the increasing number of head-worn devices, such as earbuds and smart glasses, research on gait analysis using head-worn sensors has been emerged. These head-worn sensor solutions can be used to analyze natural gait patterns in daily life at lower costs. However, these approaches are limited to spatial-temporal gait parameters, and it is so far impossible to measure joint angle movements of the lower body because angles are normally measured by at least two sensors. To overcome the limitation, it is necessary to scrutinize the relationship between the head and lower body joints. In this paper, therefore, the causality between head vertical movement and lower limb joint movements was estimated using a transfer entropy analysis during walking. In total, 12 participants' gait patterns were analyzed. Strikingly, the transfer entropy direction from the head movements to the joint angle movements was more dominant than vice versa, which was the most obvious between the head and hip. This finding can lay the groundwork for simple secondary measurement of lower limb joint problems with the simple use of head-worn sensors.