How Hearing Works
To understand hearing loss, it is important to understand how normal hearing works. Sound waves are collected by the outer ear and channeled in the ear canal to the eardrum. When sound hits the eardrum, the impact creates vibrations, which, in turn, are transferred to three tiny bones in the middle ear. The smallest of these bones, the stapes, fits into the oval window between the middle and inner ear. These bones transfer these vibrations to a sensory organ in the inner ear called the cochlea. When the vibrations from the stapes are transferred to the oval window, fluid in the inner ear transmits the vibrations into 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.