EMG Analysis Methods on Robotic Gait Machines

Abstract

Gait impairment is one of the consequences of events like stroke, traumatic brain injury, spinal cord injury or neurodegenerative diseases like Multiple Sclerosis or Parkinsons' Disease. The restoration and improvement of walking functions is one of the primary concerns of the rehabilitation of neurological Patients. To achieve this goal, a task specific repetitive training seems the most promising strategy (Jorgensen et al., 1995). Conventional physiotherapy stresses out the reduction of an elevated muscle tone and the practice of gait preparatory tasks while sitting or standing. Accordingly, the number of steps practised rarely exceeds 50 to 80 steps during one therapy session (Hesse et al., 1995). To increase the number of steps during therapy, the treadmill training with partial body weight support was a first step. Over the last years, there has been a growing support for the use of manual assisted treadmill training in neurorehabilitation programs. Studies showed that individuals who receive body weight supported treadmill training following stroke, traumatic brain injury and spinal cord injury improve their muscle activity during locomotion and gait symmetry. The main limitation with manual assisted body weight supported treadmill therapy is that a training session relies on several physical therapists to assist the patients' leg and hip movements through the gait cycle by hand. This results in short training sessions because of the physical effort required by the therapists and limits the potential of the treatment for the required training intensity may not be reached (Barbeu & Visintin 2003). Robotic Gait Machines were developed to bypass these limiting factors. The gait machines move the legs of the patients through specified patterns. This is made either by applying an exoskeleton or an end-effector principle. The exoskeleton devices known so far are the Lokomat (Colombo et al., 2000), the LOPES (Veneman et al. 2007), the AutoAmbulator (Healthsouth Corporation, 2004) and the Sara (MPD Costruzioni Meccaniche, 2010). Typical end-effector devices are the GangTrainer GT I (Hesse & Uhlenbrock, 2000), the LokoHelp (Freivogel et al., 2008), the Hapic Walker (Schmidt et al., 2005), the 6 Degrees of Freedom Gait Robot (Yoon et al., 2010) and the G-EO Systems (Hesse et al., 2010). The exoskeleton is equipped with programmable drives or passive elements which flex the knees and hips during the swing phase. With the other principle the feet are placed on foot