Objective: The aim of the study was to demonstrate the feasibility, tolerability, and effectiveness of robotic-assisted arm training in incomplete chronic tetraplegia. Design: Pretest/posttest/follow-up was conducted. Ten individuals with chronic cervical spinal cord injury were enrolled. Participants performed single degree-of-freedom exercise of upper limbs at an intensity of 3-hr per session for 3 times a week for 4 wks with MAHI Exo-II. T etraplegia caused by injury to spinal cord has a significant disabling effect on independence in daily life. Approximately half of people with tetraplegia reported regaining arm and hand functions as the most important factor to improve their quality of life.1,2 Treatment options aiming to improve upper limb motor functions are sparse; functional electrical stimulation 3 and exercise 4 are aimed at sensory-motor recovery, whereas other treatments offer functional gains with minimal or no effects on neurorecovery. For example, neuroprostheses 5 and brain computer interface systems 6 increase motor control through alternative communication and control systems, whereas reconstructive surgery of the upper limb offers permanent changes to muscle structure. 7 There is evidence that repetitive and intensive practice can induce practice-dependent brain and spinal plasticity and that exercise intensity has a profound effect on sensory-motor recovery of patients with spinal cord injury (SCI). 8,9 In this regard, rehabilitation robots hold promise for enhancing traditional physical and/or occupational therapy. They can deliver repetitive exercises at high intensities, for extended time periods, in a consistent and precise manner. In addition, real-time measurement of performance may provide advantage to therapists to modify the therapy protocol based on improvement in performance. In this context, previous studies have reported that robotic-assisted rehabilitation can improve motor recovery after stroke and that robotic devices are safe and feasible in rehabilitation.10 Despite considerable interest in robotic gait training after SCI, 11,12 very few reports have evaluated the effect of robotic training of arm and hand function in patients with tetraplegia. [13][14][15] The current study aimed to demonstrate the feasibility and tolerability and to assess effectiveness of robotic-assisted training in improving arm and hand functions in chronic, incomplete cervical SCI. We hypothesized that intense active repetitive movement training, with a robotic device, would

Robotic devices have been shown to be efficacious in the delivery of therapy to treat upper limb motor impairment following stroke. However, the application of this technology to other types of neurological injury has been limited to case studies. In this paper, we present a multi degree of freedom robotic exoskeleton, the MAHI Exo II, intended for rehabilitation of the upper limb following incomplete spinal cord injury (SCI). We present details about the MAHI Exo II and initial findings from a clinical evaluation of the device with eight subjects with incomplete SCI who completed a multisession training protocol. Clinical assessments show significant gains when comparing pre-and post-training performance in functional tasks. This paper explores a range of robotic measures capturing movement quality and smoothness that may be useful in tracking performance, providing as feedback to the subject, or incorporating into an adaptive training protocol. Advantages and disadvantages of the various investigated measures are discussed with regard to the type of movement segmentation that can be applied to the data collected during unassisted movements where the robot is backdriven and encoder data is recorded for post-processing.