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

Abstract

Background: 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. We evaluated the effects of a hybrid assistive limb robot suit on the gait of stroke patients undergoing rehabilitation.

Methods: 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.

Results: 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.

Conclusions: 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.

Figures

Figure 1

A stroke patient using the hybrid assistive limb (HAL) suit. The left image shows a patient using the HAL suit and walking with a cane, and a physiotherapist pays attention to the patient while noting his fall. In the right image, the patient is being trained to climb down stairs by a physiotherapist.

Figure 2

Changes in the stride, walking speed and physiological cost index (PCI) before and after HAL use. The HAL suit increased the stride length in 4 of 16 patients (A). The walking speed increased in 4 of 16 patients while walking with the HAL suit, and this change persisted even while walking with the KAFO after removing the HAL suit on the following day. The walking speed markedly decreased in 12 patients while wearing the HAL suit (B). The PCI values clearly decreased after wearing the HAL suit in only 2 patients. In 11 patients, the PCI values apparently increased after wearing the HAL suit, but removal of the HAL suit led to a decrease in PCI values in 8 of 12 patients to levels equivalent to or below those observed before wearing the HAL suit (C).