Brainstem response, also known as brainstem auditory evoked response (BAER) or auditory brainstem response (ABR), is a neurophysiological test used to evaluate the integrity of the auditory nerve and the brainstem pathways that process sound. This test involves monitoring electrical activity in response to auditory stimuli presented to the ears. The resulting waveforms provide information about the timing and strength of the neural responses along the auditory pathway, and can be used to diagnose hearing loss, auditory neuropathy, and other auditory disorders. Brainstem response is often used in newborn hearing screening programs and for assessing hearing function in patients who are unable to participate in traditional behavioral hearing tests.