Diseases such as measles, mumps, and spinal meningitis that are accompanied by high fever have been the cause of hearing loss in many people. These diseases can have indirect consequences as well. For example, when a pregnant woman contracts or is exposed to German measles during the first trimester of pregnancy, there is an increased risk that her child will be born with a hearing loss. The rubella (German measles) epidemic of the mid-1960s caused a significant increase in the number of deaf hand hard of hearing people. Since then, vaccinations have greatly reduced the occurrence of these diseases.
Some drugs prescribed for medical problems are ototoxic, meaning they have the potential to cause damage to the inner ear, which may result in temporary or permanent hearing loss. If you have a hearing loss, ask your doctor about the medications prescribed for you so that you can prevent an aggravation of your hearing problem (see Chapter 8).
Prolonged exposure to loud noise at or above 90 decibels can damage the sensitive hair cells lining the cochlea. This may cause partial or severe hearing loss. Occupational noise exposure, the most common form of noise-induced hearing loss, threatens the hearing of firefighters, police officers, military personnel, pilots, construction and factory workers, musicians, farmers, and truck drivers, to name a few. Nonoccupational sources of hazardous noise such as live or recorded high volume music; recreational vehicles; airplanes; lawn-care equipment; woodworking tools; household appliances such as mixers, blenders, and vacuum cleaners; and chain saws also causes hearing loss. Because no medical or surgical treatment can correct a hearing loss resulting from noise exposure, prevention is important.
Presbycusis is the term used to describe the slow, progressive type of hearing loss that is associated with aging. At age sixty-five, one out of every three people has a hearing loss. Age-related hearing loss often is due to a lifetime of exposure to dangerous levels of noise or to hereditary adult-onset hearing loss.