Of the three types of hearing loss, sensorineural hearing loss accounts for almost 90 percent. And while aging is one of the primary causes for this hearing impairment, other factors may cause it.
Individuals with sensorineural hearing loss have sustained some type of damage to, or deterioration of, their cochlea or auditory nerve. Both of these structures are located in the inner ear. The cochlea is snail-shaped and contains three, fluid-filled chambers. These chambers translate sound wave vibrations into electrical information and send them to the auditory nerve. The auditory nerve, a bundle of nerve fibers situated between the cochlea and the brain, transmits the electrical information to the brain for processing.
Sensorineural hearing loss is often referred to as “nerve damage” because of its connection to the auditory nerve. Actually, this type of hearing impairment is most often caused by damage to the hair cells in the cochlea. There are two types of sensorineural hearing loss -- acquired and congenital. Acquired sensorineural hearing loss occurs after birth, congenital sensorineural hearing loss happens during pregnancy. The degree of severity of both types range from mild to moderate and severe, including deafness.
What causes acquired sensorineural hearing loss?
The aging process. Presbycusis is the term hearing health professionals use when describing sensorineural hearing loss that’s occurred as a result of the aging process. It’s the most common type of sensorineural hearing loss in the United States and typically occurs gradually, affects both of your ears, and impairs your ability to hear high frequency sounds.
Noise. Individuals who live and work in noisy environments (in excess of 85 decibels) are at risk for sensorineural hearing loss. Loud noises cause damage to the hair cells and auditory nerve in the inner ear. Noise is damaging if you have to shout to be heard or your ears hurt or ring after exposure to loud noise.
Disease and infections. Viral infections, such as measles, meningitis, and mumps can cause damage to the inner ear. Other diseases associated with sensorineural hearing loss include Meniere’s disease and maternal diabetes.
Head or acoustic trauma. Injuries to the head and exposure to a sudden, extremely loud noise can permanently damage the inner ear.
Tumors. Examples include Acoustic Neuroma, a benign tumor that affects the auditory system and Cholesteatoma, an abnormal skin growth in the middle ear.
Medications. Some types of medications, such as high doses of antibiotics or cancer treatments, may cause this type of hearing loss.
What causes congential sensorineural hearing loss?
Sensorineural hearing loss can also be congenital, meaning the hearing loss was present at birth. Prematurity, maternal diabetes, lack of oxygen during birth, genetics and Ruebella are some causes of congenital sensorineural hearing loss.
Although most sensorineural hearing loss is permanent, individuals with this type of hearing impairment may benefit from the use of hearing aids – especially in the case of individuals with Presbycusis and other acquired sensorineural hearing loss. Those with profound congenital hearing loss may benefit from a cochlear implant, an electronic device which is implanted directly behind the ear.
As always, the first step in determining what type of hearing loss you’re experiencing is to visit your doctor or local hearing center. After a thorough hearing evaluation, a hearing health professional will interpret the results, identify the type of hearing loss you’re experiencing and recommend the best course of treatment.