Nonsyndromic Hearing Loss—Hearing Disorders and Deafness

Also called: Hearing loss, Presbycusis

It’s frustrating to be unable to hear well enough to enjoy talking with friends or family. Hearing disorders make it hard, but not impossible, to hear. They can often be helped. Deafness can keep you from hearing sound at all.

What causes hearing loss? Some possibilities are

• Heredity
• Diseases such as ear infections and meningitis
• Trauma
• Certain medicines
• Long-term exposure to loud noise
• Aging

There are two main types of hearing loss. One happens when your inner ear or auditory nerve is damaged. This type is usually permanent. The other kind happens when sound waves cannot reach your inner ear. Earwax build-up, fluid, or a punctured eardrum can cause it. Treatment or surgery can often reverse this kind of hearing loss.

Untreated, hearing problems can get worse. If you have trouble hearing, you can get help. Possible treatments include hearing aids, cochlear implants, special training, certain medicines, and surgery.

NIH: National Institute on Deafness and Other Communication Disorders

• Acoustic trauma (Medical Encyclopedia)
• Age-related hearing loss (Medical Encyclopedia)
• Audiometry (Medical Encyclopedia)
• Ear examination (Medical Encyclopedia)
• Hearing loss (Medical Encyclopedia)
• Occupational hearing loss (Medical Encyclopedia)
• Otosclerosis (Medical Encyclopedia)
• Sensorineural deafness (Medical Encyclopedia)

Nonsyndromic hearing loss is a partial or total loss of hearing that is not associated with other signs and symptoms. In contrast, syndromic hearing loss occurs with signs and symptoms affecting other parts of the body.Nonsyndromic hearing loss can be classified in several different ways. One common way is by the condition’s pattern of inheritance: autosomal dominant (DFNA), autosomal recessive (DFNB), X-linked (DFNX), or mitochondrial (which does not have a special designation). Each of these types of hearing loss includes multiple subtypes. DFNA, DFNB, and DFNX subtypes are numbered in the order in which they were first described. For example, DFNA1 was the first type of autosomal dominant nonsyndromic hearing loss to be identified.The characteristics of nonsyndromic hearing loss vary among the different types. Hearing loss can affect one ear (unilateral) or both ears (bilateral). Degrees of hearing loss range from mild (difficulty understanding soft speech) to profound (inability to hear even very loud noises). The term “deafness” is often used to describe severe-to-profound hearing loss. Hearing loss can be stable, or it may be progressive, becoming more severe as a person gets older. Particular types of nonsyndromic hearing loss show distinctive patterns of hearing loss. For example, the loss may be more pronounced at high, middle, or low tones.Most forms of nonsyndromic hearing loss are described as sensorineural, which means they are associated with a permanent loss of hearing caused by damage to structures in the inner ear. The inner ear processes sound and sends the information to the brain in the form of electrical nerve impulses. Less commonly, nonsyndromic hearing loss is described as conductive, meaning it results from changes in the middle ear. The middle ear contains three tiny bones that help transfer sound from the eardrum to the inner ear. Some forms of nonsyndromic hearing loss, particularly a type called DFNX2, involve changes in both the inner ear and the middle ear. This combination is called mixed hearing loss.Depending on the type, nonsyndromic hearing loss can become apparent at any time from infancy to old age. Hearing loss that is present before a child learns to speak is classified as prelingual or congenital. Hearing loss that occurs after the development of speech is classified as postlingual.