Although Auditory neuropathy spectrum disorder (ANSD) is not yet fully understood, scientists believe the condition probably has more than one cause. In some cases, it may involve damage to the inner hair cells—specialized sensory cells in the inner ear that transmit information about sounds through the nervous system to the brain. Other causes may include faulty connections between the inner hair cells and the nerve leading from the inner ear to the brain, or damage to the nerve itself. A combination of these problems may occur in some cases. Although outer hair cells—hair cells adjacent to and more numerous than the inner hair cells—are generally more prone to damage than inner hair cells, outer hair cells seem to function normally in people with ANSD.