Event-Related Potential

An event-related potential (ERP) is a measured brain response that is the direct result of a specific sensory, cognitive, or motor event. ERPs are extracted from electroencephalography (EEG) recordings by averaging brain signals time-locked to repeated presentations of a stimulus. In accessibility and assistive technology, ERPs are fundamental to brain-computer interfaces (BCIs) that allow people with severe motor disabilities to communicate. The most commonly used ERP in BCI systems is the P300, a positive voltage deflection that occurs approximately 300 milliseconds after an unexpected or task-relevant stimulus. By detecting these brain responses, BCI systems can determine which item a user is attending to without requiring any physical movement.