Auditory neuropathy spectrum disorder (ANSD) is a rare disorder in which hearing loss occurs due to a lack of normal middle ear reflexes and absence of brain stem response to auditory signals. This means that the auditory nerves are not working, but interestingly, hair cells in the ear are normal. Because hair cells are often normal, ANSD does not always show up on initial newborn hearing tests. 40% of ANSD cases are genetic. Symptoms include difficulty hearing noise, fluctuation in hearing ability, and low levels of speech perception. There is currently no medical treatment for ANSD, but cochlear implants and hearing aids may be used to improve hearing ability.