March 28, 2015
Deafness – Part 2
Continued from the previous blog.
Noise-induced hearing loss. Hearing damage from noise exposure typically occurs in a very restricted frequency range, creating a gap in the sequence of frequencies that can be heard. The gap is usually in the high-frequency range, which can affect a person’s ability to understand speech. However, noise damage can sometimes affect such a narrow frequency range that the person may not even be aware that he has hearing loss.
Protecting your ears from loud sounds can reduce the potential for hearing loss caused by noise exposure. Many comfortable forms of hearing protection are available, including earplugs, which fit into the ear canal, and earmuffs, which secure over the ears with a band. Some people are reluctant to wear hearing protection in noisy environments because they are concerned they won’t be able to hear others talking to them. This is not something to be concerned about, however, because most people talk louder in noisy situations, so it is possible to hear conversations even with ear protection.
I have some noise hearing loss from the military, but the tests were so poorly done, that I was not able to contest the results. Over the years, I have become more acutely aware of some sounds and often have to leave some gatherings when music is too loud.
Age-related hearing loss. As we age, hearing loss occurs gradually, beginning with the high frequencies. In general, vowels, which account for the loudness of speech, are in the low-frequency range, while consonants, which provide the clarity of speech, are in the high-frequency range. Therefore, high-frequency hearing loss may not affect how loudly sounds are heard, but it can make speech less clear and, as a result, more difficult to understand. This is especially the case when watching television or listening to the radio, where speech is often fast and where visual cues, such as lip movements and body language, are not as readily available, as well as in noisy situations.
As far as age-related changes in hearing are concerned, it’s important to remember that the ear alone is not responsible for hearing. Sound is converted into electrical signals that travel from the cochlea through a series of nerve pathways to the brain for interpretation. In addition to problems associated with physical deterioration of the hair cells in the cochlea, there are age-related changes in the processing ability of the hearing-related nerves (the central processing disorders mentioned earlier) as well as cognitive changes that may slow a person’s ability to understand speech. These changes can have a profound effect on a person’s verbal communication abilities, regardless of whether hearing loss is present. For example, a common complaint of some older people is that people talk too fast. This is because as we age, the mental processes that are needed to understand speech can overload when information is presented too rapidly. In a study, conducted at the Veterans Affairs National Center for Rehabilitative Auditory Research (NCRAR) in Portland, Oregon, it was found that older people who have poorer performance on certain cognitive tests (those related to thinking, learning, and remembering) also perform poorly on speech recognition tests (tests that use lists of sentences speeded up by a computer).
Age-related hearing loss may not be immediately evident to the person whose hearing is damaged, and as a result, his hearing may be significantly diminished before he seeks help. Indeed, older people may not think they have hearing loss at all. They can still hear a lot of sounds loudly, so they simply think that other people are mumbling. In fact, this type of hearing loss is often noticed first by friends and family who find communication becoming increasingly difficult.
Age-related hearing loss progresses at different rates in different people. Some people still have very little loss even in their 80s, although that isn’t common. It is not clear what makes some people more susceptible to hearing loss than others, but as with any other age-related condition, good nutrition, physical activity, and good prevention practices (hearing protection, in this case) can contribute to lessening the effects or delaying the onset of hearing loss.
The link between diabetes and hearing loss has been debated since the 1960s or before, and the results show that a relationship exists even when researchers account for the major factors known to affect hearing, such as age, race, ethnicity, income level, noise exposure, and the use of certain medications.
Diabetes may lead to hearing loss by damaging the nerves and blood vessels of the inner ear, the researchers suggest. Autopsy studies of diabetes patients have shown evidence of such damage.
Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Afflicting nearly 21 million people in the United States, it is a major cause of heart disease and stroke and the most common cause of blindness, kidney failure, and lower limb amputations in adults. Prediabetes, which causes no symptoms, affects about 54 million adults in the United States, many of whom will develop type 2 diabetes in the next 10 years. Prediabetes raises the risk of a heart attack or stroke even if diabetes does not develop. People with prediabetes can often prevent or delay diabetes if they lose a modest amount of weight by cutting calories and increasing physical activity.
For other information about diabetes and deafness or hearing loss please read this, this, and this article.