Sensorineural hearing loss (also called nerve deafness or sensorineural deafness) is loss of hearing resulting from problems in the inner ear, in the nerve from the inner ear to the brain, or in the brain.
Although sensorineural hearing loss is considered an idiopathic (no known cause) condition, researchers believe that other factors besides age (as in presbycusis), hereditary (as in hearing loss at birth and later in life) and environmental and physical factors (as in trauma-induced problems, tumors, noise damage and drug-induced hearing loss) may play a role in hearing loss. These factors include:
- Viral infections such as influenza, rubeola, rubella, mumps, herpes simplex and CMV.
- Vascular diseases such as leukemia and sickle cell anemia
- Autoimmune diseases such as lupus and temporal arteritis
- In babies with congenital deafness, failure to respond to sounds
- In babies with congenital deafness, no baby babbling or other baby noises
- Sounds heard are quieter, distorted and less clear
- High tones are less audible
- The sounds "s", "f", and "z" are not heard
- Speech may be difficult to understand if there is background noise
- Vertigo (dizziness and loss of balance)
The doctor will conduct a thorough ear examination, note the patient's medical history and ask about hearing problems affecting other members of the family.
Depending on the patient's condition and age, hearing tests, a head CT (computed tomography) scan or head MRI (magnetic resonance imaging), and an EEG (a test that records the minute electrical impulses produced by the activity of the brain) for hearing may be performed.
The treatment for sensorineural hearing loss is often the use of hearing aids or cochlear implants.
A hearing aid is a small electronic device that fits into the ear. A hearing aid consists of a tiny microphone to pick up the sounds, an amplifier that increases the volume and a tiny speaker that transmits sounds to the ear.
A cochlear implant is an electronic device implanted behind the ear. Unlike a hearing aid that amplifies sounds, cochlear implants directly stimulate the auditory nerve fibers in the cochlea. The implant consists of internal and external components.
The internal component is a receiver/stimulator that is positioned under the skin in a bed created in the bone behind the ear. An electrode array, consisting of 22 tiny bands arranged within a biocompatible tubing is surgically inserted approximately one inch into the cochlea.
The external components include a light-weight speech processor and a head-set composed of a directional microphone worn behind the ear and a transmitter that is held in place over the implanted receiver by small magnets.