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.
