Lateral Swing Support System for Parkinsonism patients with Freezing of Gait

Freezing of gait (FOG) is one of the typical locomotion disorders associated with Parkinsonism, and is described as the inability to move the feet despite an attempt to walk. The fear of falling over and other symptoms of FOG can be distressing to patients. Considering conventional external cues and physical therapy, it is necessary for Parkinsonism patients suffering from FOG to swing the body laterally and rhythmically. The purpose of this study is to develop a wearable system that can assist rhythmical and lateral swing, and to validate the performance of the system in preventing FOG by conducting a gait experiment on a Parkinsonism patient. To develop this system, we simulated lateral swing in the standing position based on features of Parkinsonism and defined a mechanism and appropriate force configurations for the system. A power unit at the back of the waist transmits a cyclic force to the chest through a link in the frontal plane. A gait experiment was performed on a Parkinsonism patient with FOG to confirm the reduction in duration time and number of steps of turning. The result showed that the cyclic assistance of the system and gait cycle were harmonized, and the developed system decreased duration time and number of steps during turning by half. In addition, Pre-FOG, i.e., transient small stepping gait, occurred when turning without using the system, while it did not occur during and immediately after the use of the system. These results suggest that the developed system is effective in preventing occurrences of FOG by providing lateral and cyclic force to the upper body.