The effect of a hybrid assistive limb<sup>®</sup> on sit-to-stand and standing patterns of stroke patients

Abstract

[Purpose] The Hybrid Assistive Limb(®) (HAL(®)) robot suit is a powered exoskeleton that can assist a user's lower limb movement. The purpose of this study was to assess the effectiveness of HAL(®) in stroke rehabilitation, focusing on the change of the sit-to-stand (STS) movement pattern and standing posture. [Subjects and Methods] Five stroke patients participated in this study. Single leg HAL(®) was attached to each subject's paretic lower limb. The subjects performed STS three times both with and without HAL(®) use. A tri-axial accelerometer was used to assess the STS movement pattern. Forward-tilt angle (FTA) and the time required for STS were measured with and without HAL(®) use. Surface electromyography (EMG) of STS and standing were recorded to assess the vastus medialis muscle activities of the paretic limb. [Results] The average FTA without HAL(®) use was 35° and it improved to 43° with HAL(®) use. The time required for STS was longer for all subjects with HAL(®) use (without HAL(®) use: 3.42 s, with HAL(®) use: 5.11 s). The integrated EMGs of HAL(®) use compared to those without HAL(®), were 83.6% and 66.3% for STS and standing, respectively. [Conclusion] HAL(®) may be effective in improving STS and standing patterns of stroke patients.