This paper provides a detailed design description and technical testing results of a device for studying motor learning and rehabilitation of human locomotion. The device makes use of linear motors and a parallel mechanism to achieve a wide dynamic force bandwidth as it interacts with the leg during treadmill stepping.

Significant potential exists for enhancing physical rehabilitation following neurologic injury through the use of robotic and mechatronic devices (or "rehabilitators"). We review the development of a rehabilitator (the "ARM Guide") to diagnose and treat arm movement impairment following stroke and other brain injuries. As a diagnostic tool, the ARM Guide provides a basis for evaluation of several key motor impairments, including abnormal tone, incoordination, and weakness. As a therapeutic tool, the device provides a means to implement and evaluate active assist therapy for the arm. Initial results with three stroke subjects demonstrate that such therapy can produce quantifiable benefits in the chronic hemiparetic arm. Directions for future research regarding the efficacy and practicality of rehabilitators are discussed.

An important goal in rehabilitation engineering is to develop technology that allows individuals with severe motor impairment to practice arm movement without continuous supervision from a rehabilitation therapist. This paper describes the development of such a system, called Therapy WREX or ("T-WREX"). The system consists of an orthosis that assists in arm movement across a large workspace, a grip sensor that detects hand grip pressure, and software that simulates functional activities. The arm orthosis is an instrumented, adult-sized version of the Wilmington Robotic Exoskeleton (WREX), which is a five degrees-of-freedom mechanism that passively counterbalances the weight of the arm using elastic bands. After providing a detailed design description of T-WREX, this paper describes two pilot studies of the system's capabilities. The first study demonstrated that individuals with chronic stroke whose arm function is compromised in a normal gravity environment can perform reaching and drawing movements while using T-WREX. The second study demonstrated that exercising the affected arm of five people with chronic stroke with T-WREX over an eight week period improved unassisted movement ability (mean change in Fugl-Meyer score was 5 points +/- 2 SD; mean change in range of motion of reaching was 10%, p < 0.001). These results demonstrate the feasibility of automating upper-extremity rehabilitation therapy for people with severe stroke using passive gravity assistance, a grip sensor, and simple virtual reality software.