Rehabilitation Engineering Practice Exam

Myoelectric control uses surface EMG signals from muscles to operate an externally powered prosthetic arm. Electrodes placed on the skin pick up the electrical activity generated when a user contracts residual or nearby muscles. The prosthetic’s controller analyzes the signal’s strength and patterns and translates them into movement commands for the powered joints and gripper. This makes control intuitive because the user’s muscle activations directly drive the device, similar to natural movement, but via electrical signals rather than mechanical force. This approach differs from body-powered control, which relies on a harness and cables to convert the wearer’s body movements into prosthetic actions, without using electrical muscle signals. It also differs from brain-computer interfaces, which use brain-derived signals rather than peripheral muscle activity, and from hydraulic control, which describes how the prosthesis is actuated rather than how it is controlled.