Sensorineural hearing loss occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain.

In most cases, the tiny sensory hair cells have been damaged and can no longer transduce information to the auditory nerve. Sensorineural hearing loss reduces the ability to hear faint sounds, so even when speech is loud enough to hear, it may still be unclear or sound muffled.

Sensorineural hearing loss is the most common type of permanent hearing loss. Causes of this type of hearing loss include:

Conductive hearing loss occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones (ossicles) of the middle ear. This type of hearing loss usually involves a reduction in sound level or the ability to hear faint sounds.

In many cases, conductive hearing loss can be treated and the hearing restored. Causes for conductive hearing loss include:

Mixed hearing loss is a combination of conductive and sensorineural hearing loss.