G.P.242: A trial of hybrid assistive limb (HAL) for a spinal muscular atrophy (SMA) patient

Abstract

Hybrid assistive limb (HAL) is a wearable robot device that assists gait of patients with disabilities according to the patient’s voluntary drive by detecting weak bioelectric signals on the surface of the skin. We used HAL for a patient with spinal muscular atrophy (SMA) to investigate its effect to motor function of subject and change in degree of subjective satisfaction. The subject was 13 year-old boy with SMA. He was originally able to sit with support but not able to stand or walk. Nocturnal non-invasive ventilation was adopted. He underwent HAL practice with walker 9 times for 3 months. We evaluated motor function including walking condition with walker (without assist of HAL), Modified Hammersmith Functional Motor Scale (MHFMS) score, manual muscle test (MMT), SEIQoL-DW of patient, and patient reported outcome measure (PRO) in walking before and 3 months starting practice. Assisted walking function improved after HAL practice. Maximum gait distance, gait speed, and number of steps, before practice, which were 4.55 m, 59.7 s, and 60 steps, respectively, became 6.2 m, 91.7 s, and 63 steps 3 months after. MHFMS score and MMT did not differ before and after practice, which were 2/40 points and 1–2/5 levels, respectively. SEIQoL-index before practice was 81.6%, and became 83.8% after practice. Further, SEIQoL-index of retrospective pre-test (look back) was 86.1%. The score of SEIQoL-index kept in high levels. Although patient does not gain ability of unassisted walking by using HAL, the device was effective to improve motor function of walking and quality of life of patient.