To understand hearing loss, it is important to understand how normal hearing works. Sound waves are collected by the outer ear and channeled along the ear canal to the eardrum. When sound hits the eardrum, the impact creates vibrations, which, in turn, cause the three bones in the middle ear to move. The smallest of these bones, the stapes, fits into the oval window between the middle and inner ear. When the oval window vibrates, fluid in the inner ear transmits the vibrations into the hearing organ, called the cochlea. The fluid’s wave-like action bends thousands of microscopic hair cells, setting off nerve impulses that pass through the auditory nerve to the hearing center of the brain, where they are translated into sound.