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 Hearing Loss

The gradual hearing loss that occurs as you age (presbycusis) is a common condition. An estimated one-third of Americans older than age 60 and one-half of those older than age 85 have some degree of hearing loss.

Over time, the wear and tear on your ears from noise contributes to hearing loss by damaging the cochlea, a part of your inner ear. Doctors believe that heredity and chronic exposure to loud noises are the main factors that contribute to hearing loss. Other factors, such as earwax blockage, can prevent your ears from conducting sounds as well as they should.

You can't reverse hearing loss. However, you don't have to live in a world of quieter, less distinct sounds. You and your doctor or hearing specialist (audiologist) can take steps to improve what you hear.

Impairments in hearing can happen in either frequency or intensity, or both. Hearing loss severity is based on how well a person can hear the frequencies or intensities most often associated with speech. Severity can be described as mild, moderate, severe, or profound. The term “deaf” is sometimes used to describe someone who has an approximately 90 dB or greater hearing loss or who cannot use hearing to process speech and language information, even with the use of hearing aids. The term “hard of hearing” is sometimes used to describe people who have a less severe hearing loss than deafness.

In the 2002–2003 school year, nearly 72,000 children ages 6 to 21 years got special education services under the “hearing impairment” category in the United States. Another 1,600 children received services under the “deaf blind" category. The total number of children with hearing loss is likely higher, since some of them may have other disabilities and be served under other special education categories. Still others may not be counted because they receive only regular education services.

CDC tracks the number of children in a five-county area in metropolitan Atlanta, Georgia who have  moderate to profound hearing loss in both ears. For this project, we define moderate to profound hearing loss as a 40 dB or greater loss in the better ear, without the use of hearing aids. This activity is part of the Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP). For 1991–1993, we found that, on average, about 9 in every 10,000 children ages 3 to 10 years had a moderate to profound hearing loss in both ears. Hearing loss was more common among older children than among younger children. Ninety percent of the children had a sensorineural hearing loss. Thirty percent of the children had one or more other disabilities in addition to their hearing loss. [Read a summary of the article about hearing loss in MADDSP] [Read more about MADDSP]

CDC also studied hearing loss among children in metropolitan Atlanta in the mid-1980s. This project was done as part of the Metropolitan Atlanta Developmental Disabilities Study (MADDS), which studied how common certain disabilities were among 10-year-old children. The study found that 11 of every 10,000 children 10 years of age were deaf or hard of hearing. Hearing loss was slightly more common among boys than among girls. Twenty-eight percent of the children also had another disability, such as mental retardation, cerebral palsy, or epilepsy. [Read a summary of the article about hearing loss in MADDS] [Read more about MADDS]

In the 1988 National Health Interview Survey – Child Health Supplement, parents reported that that 3.5% of children ages birth to 17 years in the United States had ever had “deafness or trouble hearing” in one or both ears. [Read a summary of the paper about hearing loss in children in 1988]

Hearing loss is more common among older people than among children. In the 1994 National Health Interview Survey Core and Second Supplement on Aging, one third of adults ages 70 and older reported that they had trouble hearing. Seven percent reported that they were deaf in both ears and another 8% reported that they were deaf in one ear. Hearing loss was more common among men than among women. [Read the report on adult hearing loss]

When describing hearing loss we generally look at three attributes: type of hearing loss, degree of hearing loss, and the configuration of the hearing loss.

Hearing loss can be categorized by where or what part of the auditory system is damaged. There are three basic types of hearing loss: conductive hearing loss, sensorineural hearing loss and mixed hearing loss.

Conductive Hearing Loss
Conductive hearing loss occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones, or ossicles, of the middle ear. Conductive hearing loss usually involves a reduction in sound level, or the ability to hear faint sounds. This type of hearing loss can often be medically or surgically corrected.

Examples of conditions that may cause a conductive hearing loss include:

Sensorineural Hearing Loss
Sensorineural hearing loss occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear (retrocochlear) to the brain. Sensorineural hearing loss cannot be medically or surgically corrected. It is a permanent loss.

Sensorineural hearing loss not only involves a reduction in sound level, or ability to hear faint sounds, but also affects speech understanding, or ability to hear clearly.

Sensorineural hearing loss can be caused by diseases, birth injury, drugs that are toxic to the auditory system, and genetic syndromes. Sensorineural hearing loss may also occur as a result of noise exposure, viruses, head trauma, aging, and tumors.

Mixed Hearing Loss
Sometimes a conductive hearing loss occurs in combination with a sensorineural hearing loss. In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve. When this occurs, the hearing loss is referred to as a mixed hearing loss.

Degree of Hearing Loss
Degree of hearing loss refers to the severity of the loss. There are five broad categories that are typically used. The numbers are representative of the patient's thresholds, or the softest intensity that sound is perceived:

Normal range or no impairment = 0 dB to 20 dB
Mild loss = 20 dB to 40 dB
Moderate loss = 40 dB to 60 dB
Severe loss = 60 dB to 80 dB
Profound loss = 80 dB or more

Configuration of Hearing Loss
The configuration or shape of the hearing loss refers to the extent of hearing loss at each frequency and the overall picture of hearing that is created. For example, a hearing loss that only affects the high frequencies would be described as a high-frequency loss. Its configuration would show good hearing in the low frequencies and poor hearing in the high frequencies. On the other hand, if only the low frequencies are affected, the configuration would show poorer hearing for low tones and better hearing for high tones. Some hearing loss configurations are flat, indicating the same amount of hearing loss for low and high tones.

Other descriptors associated with hearing loss are:

Eastern Shore ENT offers a complete range of services to evaluate hearing loss.