Study of Efficacy of the MyoTrain System in a Population of Individuals With Trans-radial Limb Loss

Mean Prosthesis Wear Duration

Investigators will measure the mean duration of daily prosthesis wear as a proxy for improved prosthesis acceptance. Prosthesis wear time is defined as the time from when participants dons their prostheses to the time they doff their prostheses. The time points are detected by skin-electrode impedance measurements through the EMG electrodes.

Assessment of Capacity for Myoelectric Control (ACMC)

In contrast to other instruments, the ACMC does not require a specific set of tools or tasks. Instead, the proctor for the measure chooses an everyday activity, such as setting up a table for snacks or replanting a flower, that is relevant to the study population. As the participants perform the chosen task, a trained rater will assess their capacity for control of their myoelectric prosthesis as represented by 30 items reflecting 6 aspects of quality of myoelectric control. These 6 aspects are "the need for external support," "grip force and opening width," "coordination of both hands, "in different positions and in motion (timing)," "repetitive grip and release," and "the need for visual feedback." Each item is scored on a 4-point scale and converted into linear measures of myoelectric control using Rasch analysis methods on the ACMC website. This outcome measure permits evaluation of bimanual tasks as well as different planes and work spaces of prosthesis use.

Clothespin Relocation Test (CRT)

The CRT has been adapted from an arm training tool to create an instrument to measure hand function. The CRT is a timed task that measures the time taken to move three standard clothespins from three locations on a horizontal bar to a vertical bar. It tests at least two motor functions simultaneously: hand open/close and wrist pronation/supination.

Module 2 of MyoTrain

At the onset of the task, a virtual hand is displayed, and a target appears in a location or orientation indicating the final target posture. The targets were specifically designed through iterative focus group testing to ensure they minimally occluded the hand and wrist position during the task. For hand grasp tasks, a translucent grey sphere represents the target location and a red sphere represents a marker tracking the virtual hand's finger position. For wrist pronation/supination tasks, a translucent grey bar appears in a target orientation and a red bar acts a visual marker indicating the virtual hand's current orientation. The goal of the task is to match the hand or wrist orientation with the target location or orientation, respectively. Four metrics are all measured during each task: Movement Completion Rate, Movement Completion Time, Number of Overshoots, and Path Efficiency. The task is failed if the participant does not complete the task within 10 seconds.

Patient-Reported Outcomes Measurement Information System (PROMIS)

PROMIS is a set of self-reported person-centered measures that evaluate and monitor physical, mental, and social health in adults and children developed by the National Institutes of Health (NIH) to improve outcome reporting across medical sciences. The PROMIS measures were designed to reduce administration time of patient reported outcomes through the use of algorithmically selected surveys. There are 5 instruments of PROMIS that we plan to use for this study: Social Isolation, Ability to Participate, Upper Limb Functionality, Physical Function, and Satisfaction Roles Activities. PROMIS measures are scored according a common metric called the T-score. Typically, the mean of 50 (standard deviation of 10) corresponds to the mean in normative U.S. population.