An assembly of devices designed for recording a localized electrical potential from the brain or spinal cord in response to stimulation (i.e., visual, auditory, and/or somatosensory) of the sensory organs, or of some point along the ascending pathway from the sensory organs, or within the central nervous system. It typically includes a sensory stimulator/stimulation system and a graphic recorder. The characteristics of the recorded potential vary with recording location, stimulus modality and level, and level of consciousness or anaesthesia. The resultant waveform may be used to assess the function and integrity of the brain and its sensory pathways.