What is Sensorineural Hearing Loss (SNHL)?
Sensorineural hearing loss (SNHL) is used to describe hearing loss caused by damage to the hair cells in the cochlea or damage to the neural pathways of hearing (nerves). The term “sensorineural” indicates two separate problems: sensory loss involving the inner ear, and neural loss involving the hearing nerve.
Previously diagnosed as “nerve deafness,” medical advances have since revealed that most often the problem lies mostly in the function of the inner ear, rather than the hearing nerve. As the two work in tandem, however, the two problems are referred to together as “sensorineural”.
As the “downstream” parts of the hearing system require input from the “upstream” sensory parts to function properly, it is important that hearing loss be treated promptly.
When present in both ears, SNHL creates difficulty understanding spoken word, even when the volume of speech seems appropriate. If only present in one ear, people may experience difficulty locating sounds or hearing in environments with heavy background noise.
For more information regarding the particulars of sensorineural hearing loss, check out this video published by Med-El.
What are the causes?
There are two types of sensorineural hearing loss; acquired and congenital. Congenital SNHL happens during pregnancy, while acquired SNHL typically develops during adulthood. Acquired SNHL can happen as the result of a variety of factors, including vaccination, aging, noise exposure, disease, infections, trauma to the head or ear, tumors, or as a side effect of medication.
What are the symptoms?
For patients that suffer with SNHL, they may experience a loss of acuity in distinguishing foreground voices against noisy backgrounds, difficulty understanding on the telephone, difficulty understanding some parts of speech, and loss of directionality of sound. Similar symptoms are also associated with other kinds of hearing loss. Audiometry or other diagnostic tests are necessary to distinguish sensorineural hearing loss from other categories of hearing loss.
How is it diagnosed?
In order to diagnose sensorineural hearing loss, a thorough review of medical history and physical examination are essential. Medical professionals may ask questions regarding when your hearing loss began, the progression of symptoms, relevant family history, and medication use, among other things.
The physical examination may include palpitation of ear tissue, examination of the external auditory canal, and an assessment of the mobility, color, and surface of the tympanic membrane. Medical professionals may run a variety of other tests following the physical examination. Weber’s test is used to determine whether hearing loss is conductive or sensorineural by striking a tuning fork on the patient’s scalp and evaluating which ear can best hear the sound. Similarly, the Rinne test uses a tuning fork to compare air conduction with bone conduction.
Following these preliminary tests, patients may be asked to sit for an audiogram. More sensitive and specific than tuning fork examination, audiograms are able to measure hearing levels in comparison with the American National Standards Institute.
What are the treatment options?
There is no proven or recommended treatment or cure for SNHL. Although sensorineural hearing loss is often permanent, some individuals may benefit from the use of hearing aids. In cases of profound or total deafness, a cochlear implant is a specialized hearing aid which may restore a functional level of hearing.
Living with SNHL
Many who suffer from SNHL experience a negative impact on both their quality of life and mental state. Some experience anxiety or depression associated with the difficulty in understanding and communicating with people in their lives, but upon treatment find restored self-confidence and improved ability to communicate. For more information regarding hearing aids, check out the National Institute on Deafness and Other Communication Disorders (NIDCD).