Gait Training with a Driven Gait Orthosis – Comparison between Lokomat and Treadmill Therapy

Rehabilitation approaches for impairments in motor function of neurologically impaired patients like stroke victims rely heavily on physiotherapy. After the introduction of treadmill training for paraplegia, there has grown a body of experience in the use of treadmill training for hemiplegia as well. Since exercising with stroke patients or paraplegic patients on the treadmill is a very demanding task for therapists, new robotic devices have been developed to assist and even increase the effect of training sessions. We report our experience and results of first recordings with the Lokomat, a PC-controlled and driven orthosis, developed to enable completely paralyzed patients to walk on a treadmill without the physical help of therapists. The patients are supported with a suspension of the body weight by a harness, when walking in a driven gait orthosis, with actuators at hip and knee joints of either side inducing cyclic gait patterns. During treadmill training periodic excitation of muscular and cutaneous receptors is supposed to stimulate neural circuits in the spinal cord to facilitate or even induce cyclic gait patterns as put forward by the concept of central pattern generators. We measured EMG activity in 4 muscles of each leg during walking on a regular treadmill as well as on a treadmill with assistance of the Lokomat. Subjects were healthy controls and 9 hemiplegic stroke patients. Our results support the hypothesis that the use of an extrinsically given cyclic leg movement will induce typical muscular walking patterns, however reduced on the paralyzed side. Faster velocities would lead to higher EMG amplitudes. Treadmill training without the Lokomat induced less pronounced muscular patterns. Gait symmetry can almost perfectly be induced by Lokomat training. In addition, patients were able to use faster velocities on the Lokomat compared to the regular treadmill, leading to a higher number of repetitive gait cycles. Since the exercise is less strenuous for patients and therapists, the duration of training can be increased producing still augmented exercise. Our data show that Lokomat training is a highly effective gait exercise for severely disabled hemiplegic patients. First results indicate that it is at least as effective as typical physiotherapeutic gait training.