Bio-Signal

Any measurable electrical, chemical, or mechanical signal produced by the human body that can be detected by sensors and used as input for computer systems. In assistive technology, bio-signals are used to create alternative input methods for people with severe motor impairments who cannot use conventional keyboards, mice, or touchscreens. Common bio-signals used in accessible computing include electromyography (EMG) from muscle contractions, electroencephalography (EEG) from brain activity (used in brain-computer interfaces), electrooculography (EOG) from eye movements, and galvanic skin response. These signals can be mapped to control commands, enabling people with conditions such as ALS, spinal cord injury, or muscular dystrophy to operate computers, wheelchairs, and communication devices using whatever voluntary muscle control they retain.