The causes of hearing loss are varied and their impact on hearing is variable. Sometimes the cause is readily apparent, such as a wax build-up in the external ear canal or an ear infection. At other times, the causes of hearing loss must be discovered through examination and technology. Whatever the cause, it is important to seek help for any hearing loss. The six most common causes are below:
1. Excessive noise
A single shot from a shotgun at close range may permanently damage your hearing in an instant. Repeated exposures to loud noise from machinery or other causes may damage your hearing over an extended period of time. Excessive noise exposure damages the delicate hair cells in the inner ear. This often results in permanent hearing loss and tinnitus (ringing in the ears). Hazardous noise exposures can occur on the job or from firearms, firecrackers, power tools, music concerts, dance clubs, NASCAR, sporting events, motorcycles, motorboats, snowmobiles, etc. If you have to raise your voice to shout over the noise to be heard by someone within an arm’s length away, that noise could be a serious risk to your hearing. If you must be in situations that expose you to loud levels of noise, please see us for custom or non-custom hearing protection!
2. Ear infections (otitis media)
Otitis media means “inflammation of the middle ear,” as a result of a middle ear infection. It is the most common cause of hearing loss in children and occasionally affects adults. The infection can cause severe earache and hearing loss. Immediate attention from your doctor is the best action. Damage from an ear infection can cause chronic or permanent hearing loss.
3. Aging (presbycusis)
Presbycusis is the loss of hearing that occurs gradually in most individuals as they grow older, typically in both ears equally. Approximately 30-35% of adults between 65 and 75 years of age have a hearing loss, and it is estimated that 40-50% of people 75 and older have a hearing loss. The loss associated with presbycusis is usually greatest for high-pitched sounds (e.g., chirping of a bird or the ringing of a telephone), while the same person may be able to hear clearly the low-pitched sound of a truck rumbling down the street (NIDCD/NIH, 2013).
4. Injury to the head or ear
A blow to the head may change the position of the three bones of the middle ear (ossicular dislocation), resulting in sound not being sent to the inner ear. A head injury may also cause a ruptured eardrum (tympanic membrane perforation). Or, a forceful blow to the head may damage the delicate nerves in the inner ear (cochlea) or in the brain (webmd, 2013).
5. Birth defects or genetics
Hearing loss is one of the most common birth defects (about 3-4 in 1,000 newborns). Hearing loss present at birth is called congenital hearing loss, but hearing loss also can also develop later in childhood or during adulthood. About 90% of babies with congenital hearing loss are born to hearing parents. Genetic factors are believed to cause about 50% of cases of congenital hearing loss, and about 25 genes that play a role in hearing loss have been identified. Illnesses that can cause congenital hearing loss include infections during pregnancy, such as rubella (German measles), cytomegalovirus, toxoplasmosis, herpes or syphilis. Babies born preterm also are at increased risk (March of Dimes, 2006).
6. Ototoxic reactions to drugs or cancer treatments (e.g., antibiotics, chemotherapy, radiation)
Certain medications can damage the ear, resulting in hearing loss, tinnitus (ringing in the ears), or balance disorders. These drugs are considered ototoxic. There are more than 200 known ototoxic drugs (both prescription and over-the-counter) on the market, and include medicines to treat serious infections, cancer, and heart disease. Sometimes hearing and balance problems caused by these medications can be reversed when drug therapy is discontinued, but sometimes the damage is permanent (Cone et al., ASHA.org, 2013).