The National Institutes of Health (NIH) estimates that approximately 37.5 million American adults have a significant hearing loss. As one of the most common issues plaguing individuals over the age of 12, researchers are still studying all the possible causes of hearing loss.
There have been significant strides made in the last century to better understand the many reasons behind hearing loss. The causes of hearing loss include: inherited, age related, noise induced, acquired from illness, ototoxic drugs, tumors or head injuries.
It is important to understand the causes of hearing loss in order to find the right treatment.
Inherited hearing loss
Hereditary hearing loss can be conductive, sensorineural or mixed and is the result of a genetic trait passed down from a parent. A study performed by the University of Washington, Seattle reports there are more than 400 known genetic syndromes that include hearing loss.
Some of these include:
- Waardenburg syndrome
- Branchiootorenal syndrome
- Stickler syndrome
- Usher syndrome
- Pendred syndrome
- Alport syndrome
While many hereditary hearing losses are congenital (or present at birth), some of these conditions develop slowly over time.
Age-related hearing loss
Age-related hearing loss, or presbycusis, is the gradual loss of hearing that occurs in people over time. This type of loss is permanent and is generally greater for higher-pitched tones, such as birds chirping or the ringing of a telephone.
There are numerous symptoms of age-related hearing loss, but the main ones include: complaining of hearing other's mumbling, difficulty understanding conversations (especially in background noise), certain sounds seeming annoying or too loud, and tinnitus may be reported.
Because presbycusis is a type of sensorineural hearing loss, it commonly occurs from changes in the inner ear as a person ages. It also can be the result from changes in the middle ear or along the nerve pathways leading to the brain. Changes in the blood supply to the ear from heart disease, high blood pressure or vascular conditions may also contribute to age-related hearing loss.
Presbycusis can also be identified as a conductive hearing disorder. When this happens, the loss of sound sensitivity is caused by abnormalities of the outer ear or middle ear. Because of these abnormalities, function of the three small ear bones or eardrum is reduced and then decreases hearing ability over time.
Presbycusis usually affects both ears equally and gradually. Because it develops slowly over time, this can be a difficult hearing loss for the individual to recognize.
Noise-induced hearing loss
Noise-induced hearing loss is caused by prolonged exposure to loud noise. The culmination of constant exposure to everyday sounds like traffic, construction work, noisy office environments or loud music can negatively impact your hearing. While noise-induced hearing loss is generally temporary in nature, repeated overexposure to loud music damages inner ear hair cells, causing hearing loss to deteriorate over time and become permanent.
The Center for Disease Control and Prevention estimates that more than one out of 10 persons aged 6-19 has already suffered permanent damage to their hearing from excessive exposure to loud noise. Culprits of exposure include: loud music from headphones, stereos and converts, in addition to construction and other work equipment noises.
The important thing to remember is noise-induced hearing loss is preventable. Individuals can lower their risk of noise-induced hearing loss by limiting their exposure to loud noises, utilizing earplugs when saturated in noisy environments, turning down the volume of music or sound on personal music device and using a volume-limiter device when using personal audio equipment.
Illness-related hearing loss
In addition to hereditary hearing loss, there are numerous illnesses and disorders individuals can develop over time which contribute to hearing loss. Otosclerosis is a disease that affects the movement of the tiny bones in the middle ear. This can cause a conductive type of hearing loss and is usually surgically treatable.
Meniere’s disease is another example of an illness which negatively impacts a person’s hearing. The cause of this disease is unknown, but symptoms usually include sensorineural hearing loss, vertigo, ringing in the ear and sensitivity to loud noises. This type of disorder can remain temporary, but over time may become permanent.
An autoimmune inner ear disease generally causes a sudden hearing loss that is fast and should be medically treated as soon as possible. With fast intervention, the hearing loss from this disease can be minimized.
Individuals with these types of hearing loss often recognize symptoms, but can have a hard time identifying the particular disorder.
There are numerous types of medications that have been linked to hearing loss.
Generally an individual must consume large quantities of these types of drugs to notice effects of hearing loss, but research is still being performed to further understand. Some of the medications known to be ototoxic are: aminoglycoside antibiotics, aspirin, nonsteroidal anti-inflammatory drugs and drugs used in chemotherapy regimens.
Hearing loss caused by ototoxic medication is generally considered permanent.
Hearing loss related to tumors or head injury
Another cause for hearing loss is from tumors or head injury. An acoustic neuroma is an example of one type of tumor which directly causes hearing loss. Individuals with tumor-related hearing loss might experience tinnitus (ringing in the ears) or might have a sensation of fullness in one or both ears. Sound will be somewhat fuzzy and incongruent, leaving individuals with an almost fuzzy-like feeling in their heads. Hearing loss related to tumors is usually treated either medically or surgically and can result in either a temporary or permanent hearing loss.
In the event an individual suffers a physical injury to the head, it is possible that the inner ear structures and canals may be traumatized, causing a temporary or permanent hearing loss. Any injury sustained by the head should be evaluated by a doctor, which will most likely include both a hearing and eye examination.
Understanding the causes of hearing loss can better help a hearing healthcare professional treat the individual. Anyone experiencing symptoms of hearing loss should visit a hearing practitioner to be examined.
- Quick Statistics, National Institute on Deafness and Other Communication Disorders, www.nidcd.nih.gov/health/statistics/Pages/quick.aspx
- Noise-Induced Hearing Loss, centers for Disease Control and Prevention, http://www.cdc.gov/healthyyouth/noise/