Wearable Exosuit Device to Actively Assist Upstairs Walking for FSH Muscular Dystrophy Patients

Abstract

Facioscapulohumeral (FSH) Muscular Dystrophy is a neuromuscular disease characterized by progressive muscle weakness and atrophy in many muscles, including the pelvic girdle muscles. Many patients with these symptoms experience difficulty walking up stairs. This project develops a device to assist upstairs walking for FSH patients, with the design stemming from previous work by the Harvard BioDesign Lab. The device is the first of its kind, as all existing devices are passive or are not low-profile. The final device is a soft, wearable exosuit that provides assistance during hip extension through Bowden cable actuation. The final device was created through a user-centered design process, being both low-profile and lightweight. Human testing showed that the device is able to consistently provide a peak moment of 17.25 Nm at the hip using load feedback, adjusting for variable initial cable slack and stair size. It can be worn discretely underneath clothing and weighs only 2.0 kg. Using a foot switch to sense foot strike, the device is able to provide assistance at the appropriate time in the gait cycle. The device must be charged only once a week with batteries providing 81.5 watt hours.