Consumer Criteria for an Arm Orthosis

For people with muscular dystrophy and spinal muscular atrophy conditions characterized by degenerating muscle strength there is a need for an exoskeletal mechanism that allows the person to move their arms about freely. This paper presents a consumer-based design approach in order to construct such an assistive manipulation device and details the initial stages that have been addressed in an orthosis design project within the Applied Science and Engineering Laboratories. Two consumer meetings were held during the initial stages of the design. The results from these meetings are presented. A design principle has been established and an initial set of prototypes evaluated. These will be used to modify subsequent design iterations. Introduction Disabilities such as muscular dystrophy affect the strength of a person’s muscles, yet leave sensation and residual muscular control intact. It is hypothesized that augmenting residual arm function, rather than replacing it with a remotely controlled device such as a robot, is a more effective solution. An ongoing project within the robotics laboratory of the Applied Science and Engineering Laboratories (ASEL) explores methods of augmenting function via a powered orthosis that can support a person’s arms against gravity and provide full range of arm movement. Control of such an orthosis is achieved either by amplifying the person’s residual strength or by using signals obtained from other body sites. Individuals with either total paralysis or absence of sufficient muscle tone for performance of desired arm function, are the focus of this study. The aim for the final system is to have an orthosis that can be mounted to a wheelchair. This decision both suits the needs of the target population and makes the engineering a more tractable proposition.