Sensorineural hearing loss

The most common of the three types of hearing loss (with the other two conductive and mixed hearing loss) is sensorineural hearing loss. This type of hearing loss occurs when there is damage to the tiny hair cells in the inner ear or the auditory nerve. It can occur suddenly or throughout a lifetime. This type of hearing loss can affect both ears (bilateral) or one ear (unilateral).

Definition

Sensorineural hearing loss develops when the tiny hair cells that detect sound and the hearing nerve that transmits sound waves to the brain are impaired. Damage caused by age, sound, or disease ultimately sets off a hearing loss. Hair cells in the inner ear are unable to regenerate themselves, and there are no drugs that will help restore them. As a result, a hearing loss is permanent.

Symptoms

Sensorineural hearing loss advances gradually and becomes worse over time. Many people are often unaware that their hearing has become worse. The exception is sudden hearing loss that develops rapidly within a few hours or days. The first sign of hearing loss can be the absence of soft sounds such as the rustling of leaves, the whisper, or other low-frequency sounds. Other symptoms include difficulty hearing when the speaker’s face is not visible, or understanding conversation when there is high noise in the background.

Causes

The most frequent cause is age-related. Age-related hearing loss or presbycusis affects 1 in 7 people over the age of 65. It mainly affects sounds within the high-frequency range, and usually affects both ears (bilateral) the same way. Sometimes, hearing loss can be higher in one ear than the other. In this case, it’s regarded as an asymmetric hearing loss.

While age-related hearing loss is connected to the natural course of time, noise-induced hearing loss, such as a loud workplace or rock concert, has become more prevalent nowadays. Six to eight hours of noise above 85dB daily can cause hearing loss. Many people are repeatedly exposed to dangerously loud sounds in everyday life. For example, running a vacuum creates a sound of about 75dB, which can lessen hearing over time.

Noise-related hearing loss is also one of the widely recognized occupational illnesses in the United States. Having your headphones up too loud, or even mowing your lawn too frequently without ear protection, can put you at risk of severe damage to your ears.

Additional reasons for hearing loss include certain types of diseases (mumps, meningitis, Ménières disease), tumors, specific medications, head trauma, or rubella during pregnancy. A genetic predisposition and tinnitus (a constant ringing or buzzing in the ears) may also be the contributing factors.

Tests

An initial hearing loss examination is the physical examination used to detect if there are any problems in the ear canal or with the eardrum. After the physical examination, your hearing will be tested. A hearing test will help an audiologist to diagnose whether or not you experience a hearing loss. If so, how serious it is and if you can benefit from hearing aids. A hearing test usually involves several different tests such as a pure tone test, a bone conduction test, a speech test, and tympanometry, which evaluates the condition of the middle ear and the eardrum. The results from all these hearing tests are summarized in the form of an audiogram.

Other relevant tests are the Rinne and Weber tests, where a screening test for hearing is performed with a tuning fork to determine whether you may have conductive or sensorineural hearing loss. Bone and air conduction are tested during these two exams.

Treatment

Unfortunately, the sensorineural hearing loss type cannot be treated by medicine or surgery. The hair cell in the inner ear or the hearing nerve cannot be repaired or replaced, so the impairment is irreversible. An age-related hearing loss, for example, typically worsens over time. If left untreated, hearing loss can have serious side effects like social isolation and a lower quality of life and also increase the risk of disability. The good news is that you can successfully manage your hearing loss with the help of hearing aids or cochlear implants.

If you choose to treat your hearing loss, the best place to start is with your local audiologist.