Efficacy of a hybrid assistive limb in post-stroke hemiplegic patients: a preliminary report

The study group comprised 16 stroke patients with severe hemiplegia. All patients underwent gait training. Four patients required assistance, and 12 needed supervision while walking. The stride length, walking speed and physiological cost index on wearing the hybrid assistive limb suit and a knee-ankle-foot orthosis were compared.The hybrid assistive limb suit increased the stride length and walking speed in 4 of 16 patients. The patients whose walking speed decreased on wearing the hybrid assistive limb suit either had not received sufficient gait training or had an established gait pattern with a knee-ankle-foot orthosis using a quad cane. The physiological cost index increased after wearing the hybrid assistive limb suit in 12 patients, but removal of the suit led to a decrease in the physiological cost index values to equivalent levels prior to the use of the suit.Although the hybrid assistive limb suit is not useful for all hemiplegic patients, it may increase the walking speed and affect the walking ability. Further investigation would clarify its indication for the possibility of gait training.The issue of nursing care in an ageing society is a major social concern and will continue to be so in future. Therefore, robotic devices are expected to be widely used in various applications including support for the independent mobility of the elderly with muscle weakness and people with impaired motor function as well as support for nursing care that involves heavy laborious work [1-3]. The hybrid assistive limb (HAL) suit does not merely use the concept of power assist; it is a hybrid system composed of a 'cybernics voluntary control system' that provides complete control of the HAL suit using bioelectric signals and a 'cybernics robotic autonomous control system' that autonomously generates motor patterns reflecting characteristics of human motion (Figure 1). It is the world's first cyborg-type robot that takes advantage of cybernics that integrate human, mechanic