The study was stopped because of recruitment challenges and sponsor's decision to pivot to a new study outside the US

This study tests how well the Phantom X prosthesis control system works. The system helps control a prosthetic hand using muscle signals from the arm. You'll wear a non-invasive version for one day in the clinic. You'll practice hand movements and then do two simple tasks with both your usual prosthesis and the Phantom X system. At the end, you'll fill out short surveys about your experience.

The goal of this study is to evaluate the functional performance of the Phantom X prosthesis control system using a non-invasive version of its 32-electrode sensor array. All other components, including the Fusion Port, will be in their final clinical form factor, consistent with those used in future implantable configurations. The study will take place during a single, in-clinic session. Informed consent will be obtained either remotely prior to the visit or at the start of the session. Participants will undergo an initial EMG screening to determine signal suitability. Those with insufficient signal quality will be excluded. Eligible participants will be fitted with a universal socket, prosthesis, and the Phantom X system. Accelerometers will be placed on both limbs for movement tracking. Participants will practice a predefined set of gestures, followed by system calibration. Two validated functional assessments, Assessment of Capacity for Myoelectric Control (ACMC) and Targeted Box and Blocks Test (tBBT), will be conducted under two conditions: with the participant's baseline setup (if applicable) and with Phantom X. The testing order will be randomized. Participants will complete a user satisfaction questionnaire and NASA Task Load Index instrument to measure intuitiveness of Phantom X system before exiting the study.

Inclusion Criteria:

1. Individuals 21 years in age and older
2. Individuals with unilateral or bilateral amputation at transradial level
3. Patient is willing to comply with study protocol and make required study visits
4. Willingness and ability to sign Informed Consent

Exclusion Criteria:

1. Cognitively impaired to follow study instructions
2. Allergies to skin adhesive materials necessary for cutaneous electrode placement
3. Excessive hair growth on arms and inability to shave off the hair for electrode placement
4. Pregnant woman
5. Residual limbs of insufficient diameter or length to accommodate the wearing of two cutaneous sensor arrays
6. Injuries, bruises, or open wounds on the arm that needs to be instrumented for the study