Causes and Statistics of Hearing Loss
Hearing loss comes in two general forms. The first, congenital hearing loss, is hearing loss that occurs at birth. The second, acquired hearing loss, happens after birth, often later in life. The causes of these two types of hearing loss are quite different, as are the rates of prevalence for each. Acquired Hearing loss is by far the most common type of hearing loss in the U.S. and around the world. Conversely, congenital hearing loss affects less than 1% of the population. Although the causes are different, each has a range of treatment options, with some including surgery or medication, and others requiring the use of hearing aids to recover the ability to hear.
If you have experienced any of the following potential causes of hearing loss, it is important to contact us at Elite Hearing Center to properly diagnose the form of hearing loss you experience. Once the cause is known, you will be able to move forward with a treatment plan.
Acquired Hearing Loss
Acquired hearing loss comes after birth or in many cases later in adulthood. The most common type of acquired hearing loss is presbycusis. Presbycusis is a fancy term for age-related hearing loss. Another common type of acquired hearing loss is noise-induced hearing loss. As its name states, this is hearing loss caused as a result of exposure to excessively loud noise. These and other types of acquired hearing loss are described below.
For most individuals, hearing loss comes along with aging as a natural process, simply being exposed to the sounds in everyday life. As one ages, the cells in the cochlea which pick up sound and turn them into nerve signals break down and cease to function optimally. This decrease in cochlear function begins in the areas of the cochlea which process high-frequency sounds. The consonant sounds such as /s/ as in “Sam” and /p/ as in “Paul, /t/ as in “Tom” are in the high frequency range. Vowels, on the other hand, are in the low-frequency or bass region. An individual experiencing high-frequency hearing loss will have difficulty with the clarity of speech since he or she is missing some or all of the consonant sounds; therefore, speech will sound unclear. The individual will know that someone is speaking since he/she is hearing the vowels sounds and other low-frequency parts of speech, but the conversation will sound muffled, or sound like the person speaking is mumbling.
The decrease in the ability to hear high-frequency sounds typically start around age 40 and gradually proceeds in severity over time. About 2 percent of adults aged 45 to 54 have disabling hearing loss. The rate increases to 8.5 percent for adults aged 55 to 64. Nearly 25 percent of those aged 65 to 74 and 50 percent of those who are 75 and older have disabling hearing loss.6
Noise Induced Hearing Loss
Hearing loss may be caused by exposure to excessive noise. The human ear is only able to tolerate a certain level of sound before damage occurs. Extremely loud sounds such as a gun shot can cause immediately damage to the ear. Other loud sounds such machine noise, can be harmful if exposure occurs for long periods of time. Factory workers are prone to noise-induced hearing loss because they are exposed continuous loud noise for eight to ten hours daily.
There are over 200 medications known to be toxic to the ear and to put the exposed person at risk of hearing loss. Beyond these medications, other chemicals can be ototoxic, including some that may be used in workplaces. One of the first signs of ototoxicity is tinnitus, or ringing in the ears. If you are experiencing prolonged tinnitus and are unsure of the cause, consult with your doctor about the medications you are taking. It is possible that one or more of them may be ototoxic.
Baceterial and viral infections can also cause damage to the ear resulting in permanent hearing loss. Measles, mumps, meningitis, chicken poxs, and influenza and many other infections may result in permanent hearing loss.
Head trauma- Severe head trauma may result in structural damage to the parts of the ear. Structural damage to the eardrum, bones in the middle ear, or inner ear can all result in hearing loss or even complete loss of hearing.
Chronic diseases- long-term diseases such as hypertension (high blood pressure) or diabetes can affect the ear. The inner ear is a sensitive organ relying on proper blood flow from other parts of the body. Studies have shown a correlation between chronic diseases such as diabetes and hearing loss.
Congenital Hearing Loss
The statistics on how many children are born with hearing loss range from 1 to 6 newborns out of 1,000 who enter the world with some form of hearing impairment. Many birth complications and developmental abnormalities can cause hearing loss from the moment of birth. Some of the most common causes of congenital hearing loss include:
It is important to note that genetic variation may lead to hearing loss at birth or later in life. The genetic material predisposing a person to hearing loss may come from the mother or father, and the gene causing hearing loss may be a recessive gene, or one that does not manifest in the parent at all. Down syndrome is a common genetic condition that may cause hearing loss, but other genetic syndromes that may cause hearing loss include: Alport syndrome, Crouzon syndrome, Treacher Collins syndrome, Usher syndrome, and Waardenburg syndrome.