Hearing loss is categorized as conductive hearing loss or sensorineural hearing loss. Conductive hearing loss is caused by an inability of sound to reach the inner ear. Sensorineural hearing loss is due to a failure of the auditory nerve or cochlea to transmit sound messages to the brain. In some cases, people have both conductive hearing loss and sensorineural hearing loss.

The individual with both sensorineural hearing loss and conductive hearing loss may have had one type of hearing loss start before the other or had both kinds of hearing loss occur simultaneously. One or both types of hearing impairment may start suddenly or develop gradually.

Having both conductive hearing loss and sensorineural hearing loss is called mixed hearing loss. If a tumor blocks the transmission of sound to the inner ear and also interferes with the functioning of the cochlea or auditory nerve, the tumor causes both sensorineural hearing loss and conductive hearing loss.

Other possible causes of mixed hearing loss are aging, head trauma, and exposure to noise. Repetitive or long-term exposure to noise as might be part of an industrial setting can cause sensorineural hearing loss. A sudden, loud noise like a gunshot or explosion can cause the eardrum to rupture. The perforated eardrum may stop sound from being able to travel to the inner ear. This causes conductive hearing loss.

Both types of hearing loss can be caused by changes brought about by aging. The small bones of the middle ear can become rigid and less able to transmit the vibrations of sound to the inner ear. The rigidity of these small bones is called otosclerosis. This conductive hearing loss can be in addition to sensorineural hearing loss brought about by lifelong exposure to noise that is relatively common in older adults.

When a person is experiencing both kinds of hearing loss, the physician or hearing professional needs to evaluate the causes and severity of the hearing impairment before recommending treatment. Hearing aids can often help people with both types of hearing impairment. While some causes of conductive hearing loss may be surgically repaired, the causes of sensorineural hearing loss typically are not treated surgically.

Hearing aids might be able to help.