Gait Training for Becker's Muscular Dystrophy Using Robot Suit Hybrid Assistive Limb

Case Report

Phys Med Rehabil Int. 2014;1(3): 4.

Gait Training for Becker's Muscular Dystrophy Using Robot Suit Hybrid Assistive Limb

Asai T1, Ojima I1 Minami S1 Takeshima Y2 and Matsuo M1 3*

1Department of Physical Therapy, Kobegakuin University, Japan

2Department of Pediatrics, Hyogo College of Medicine, Japan

3Kobe University, Japan

*Corresponding author: Matsuo M, Department of Physical Therapy, Kobegakuin University, Japan

Received: October 03, 2014; Accepted: October 12, 2014; Published: October 14, 2014

Abstract

Becker's muscular dystrophy (BMD) is an X-linked recessive inherited disorder characterized by a slow and degenerative muscle weakness of the legs and pelvis. The patients eventually use walking aids or are wheelchairbound in daily life because of the progression of disability. The robot suit hybrid assistive limb (HAL) is a new robot suit designed to assist voluntary control of lower limb motion by detecting extremely weak bioelectric signals on the skin surface. Here we report how HAL gait training can be adapted for a wheelchairbound patient with BMD. A 25-year-old patient with BMD participated in HAL gait training.Gait training consisted of three phases: phase 1, adaptation of HAL for the patient; phase 2 (1 year), treadmill training with the body-weight supported walker (BWSW); and phase 3 (2 years), gait training on the floor with the BWSW. The subject completed 2 h of HAL gait training once a week (from August 2011 to August 2014). Although there are no standard exercises for patients with BMD, his gait ability and fitness improved, following HAL gait training. This result indicates that HAL gait training can be both feasible and safe when used as a part of a regular rehabilitation program for patients with BMD. Harness use seems to be essential for safety and feasibility of HAL gait for patients with BMD. The combined use of the HAL gait training and BWSW may be an effective rehabilitation tool for patients with BMD.

Keywords: Becker's muscular dystrophy; Hybrid assistive limb; Gait exercise; Body-weight supported walker

Introduction

Becker's muscular dystrophy (BMD) is an X-linked recessive inherited disorder, characterized by a slow and progressive degenerative muscle weakness of the legs and pelvis. Severity of the disease may markedly vary depending on the age of the patient at disease onset [1]. The patients eventually use walking aids or are wheelchair-bound in daily life because of progression of disability [2]. Rehabilitation exercises differ for ambulatory and wheelchair-bound patients. Gait training, activities of daily living (ADL) exercises and conventional physical therapy (stretching and range of motion at the lower limb joints) are practiced for ambulatory patients. Once patients become wheelchair-bound, gait training is no longer practiced; rehabilitation efforts instead focus on ADL exercises to maximize independent living.

The robot suit hybrid assistive limb (HAL) is a new robot suit designed to assist voluntary control of the knee and hip joint motion by detecting extremely weak bioelectric signals on the surface of the skin [3-5]. The HAL can support the wearer's lower limb motion while walking by adjusting the supportive level [3]. The HAL gait training is being increasingly employed for patients suffering from acquired neurological disease, such as stroke or spinal cord disease [4-9]. However, no studies have attempted to examine the feasibility of HAL rehabilitation for patients with BMD. Here we report a case in which the patient was wheelchair-bound and rehabilitation gait training had ceased. We report how HAL gait training can be adapted for use by a wheelchair-bound patient with BMD. Gait ability was influenced by HAL training.

Case Presentation

A 25-year-old patient with BMD (height, 164 cm; weight, 54 kg) participated in HAL gait training. He was diagnosed with BMD by dystrophin immune-staining of biopsied muscle tissue at 9 years of age because of the appearance of motor function deficits [10]. After the onset of BMD symptoms, his physical function gradually declined, and he began using a wheelchair outdoors at the age of 15. At the age of 22, walking was no longer possible. From the age of 23, he participated in conventional physical therapy, including muscle strength and range of motion exercises, twice a week in preparation for HAL gait training. At the age of 25, he started HAL gait training in addition to conventional physical therapy. Prior to participating in HAL gait training, the subject provided informed consent; the study was approved by the Ethics Committee of the Kobegakuin University (HEB121211-1).

Mode Setting of HAL

The HAL has a hybrid control system consisting of Cybernic Voluntary Control (CVC) and Cybernic Autonomous Control (CAC) [9]. The CVC supports the patient's voluntary lower limb motion according to the voluntary muscle activity and assistive torque provided to each joint. In this study, we used the CVC, which allows the operator to adjust the degree of physical support to the patient's comfort. In addition, the HAL has two modes, walking mode and stand up mode, which support voluntary movement of walking and standing up, respectively, according to the electrical signals of muscle contracture and load on the feet. In this study, we used the walking mode for gait training and stand up mode for sit-to-stand exercises. Furthermore, we monitored the heart rate during gait training to ensure that the working load was safe and appropriate.

Training

Gait training consisted of three phases: phase 1, adaptation of HAL for the patient; phase 2, treadmill training with the body-weight supported walker (BWSW); and phase 3, gait training on the floor with the BWSW. Typical gait training (phases 1 and 2) proceeded as follows: attaching electrodes, wearing the HAL and harness, and setting up the computer (45 min); HAL gait training (60 min, including rest time); removing the HAL and harness (15min). In phase 3, five sit-to-stand exercises (5STS) were added after gait training. All gait trainings and 5 STS were conducted by three physical therapists. The training phase is summarized in Table 1.