There are many causes of presbycusis. Most commonly it arises from changes in the inner ear of a person as he or she ages, but presbycusis can also result from changes in the middle ear or from complex changes along the nerve pathways leading to the brain. Presbycusis most often occurs in both ears, affecting them equally.
Sensorineural Hearing Loss
Sensorineural hearing loss is caused by disorders of the inner ear or auditory nerve. Presbycusis is usually a sensorineural hearing disorder. It is most commonly caused by gradual changes in the inner ear. The cumulative effects of repeated exposure to daily traffic sounds or construction work, noisy offices, equipment that produces noise, and loud music can cause sensorineural hearing loss. Sensorineural hearing loss is most often due to a loss of hair cells (sensory receptors in the inner ear). This can occur as a result of hereditary factors as well as aging, various health conditions, and side effects of some medicines (aspirin and certain antibiotics).
Presbycusis may be caused by changes in the blood supply to the ear because of heart disease, high blood pressure, vascular (pertaining to blood vessels) conditions caused by diabetes, or other circulatory problems. The loss may be mild, moderate, or severe.
Conductive Hearing Disorder
Sometimes presbycusis is a conductive hearing disorder, meaning the loss of sound sensitivity is caused by abnormalities of the outer ear and/or middle ear. Such abnormalities may include reduced function of the tympanic membrane (the eardrum) or reduced function of the three tiny bones in the middle ear that carry sound waves from the tympanic membrane to the inner ear.
Exposure to Loud Noises
More often, hearing loss is caused by exposure to loud noises. Much of the hearing loss caused by noise exposure can be prevented. Awareness of potential sources of damaging noises, such as firearms, snowmobiles, lawn mowers, leaf blowers, woodworking machinery and loud appliances is important. Ear plugs or special fluid-filled ear muffs can give protection and should be worn to help avoid the possibility of damage to hearing. Excessively loud everyday noises, both at home and at work, can pose a risk to a person's hearing. Avoiding loud noises and reducing the amount of time one is exposed to everyday noises may be helpful.