GaMA Metric to Quantify Functional Importance of Various Upper Limb Prosthetic Devices

Evaluating the benefit of new prosthetic components and control mechanisms can be challenging, as most validated outcome measures assess the time required to complete various tasks without assessing the quality of the movement or the specific DOF(s) activated to accomplish the task. There are no adequate methods to evaluate the impact of new technology. The functional outcome measures recommended by The Academy of Prosthetics and Orthotics Upper Limb Prosthetic Outcome Measures (ULPOM) committee, which provided recommendations for measuring functional effectiveness of prosthetic treatment, mainly focus on the time to complete the task rather than assessing the compensatory movements.

The Gaze and Movement Assessment (GaMA) is a new validated and standardized metric to quantify the functional characteristics of prosthesis use by quantifying motion (three dimensional angular kinematics), gaze behavior and performance during simulated real-world tasks. There are two tasks, the Cup Transfer Task and the Pasta Box Task, used with the GAMA testing hardware. The tasks require movements representing day-to-day functional requirements, while challenging typical prosthetic limitations such as reaching and transporting objects at varying heights and across the body and lack of wrist motion. Each task can be subdivided into specific phases of reaching, grasping, transporting and releasing objects. A performance aspect encourages the participant to work efficiently, and tasks are short to allow multiple repetitions within a reasonable testing time frame to assess performance consistency. By breaking down each task into movements (i.e., of the pasta box from one shelf to the next), and each movement into specific phases (reach, grasp, transport, and release), the investigators can examine these components individually. It is hypothesized that additional degrees-of-freedom (for example wrist flexion) may require more time but will reduce the compensatory movements required to complete the tasks.

The primary endpoint of the study is to quantify the effect of various prosthetics components on kinematics.

The secondary endpoint is to obtain normative data for the GaMA system and system validation.

Inclusion criteria

• A unilateral upper limb amputation or absence below the elbow
• Ability to use a myoelectric prosthesis
• English Speaking

Exclusion criteria

• Significant new injury that would prevent use of a prosthesis: The ability to consistently wear a prosthesis and perform activities of daily living and specific performance tasks is necessary to evaluate the relative benefits of the interventions.
• Cognitive impairment sufficient to adversely affect understanding of or compliance with study requirements, ability to communicate experiences, or ability to give informed consent: The ability to understand and comply with requirements of the study is essential in order for the study to generate useable, reliable data.
• Significant other comorbidity: Any other medical issues or injuries that would preclude completion of the study, use of the prostheses, or that would otherwise prevent acquisition of useable data by researchers