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Hearing Loss

With age, often, comes hearing loss. There are two main reasons for this. First, as a person ages, everything becomes less flexible. That includes the eardrum, a membrane that works by vibrating in response to sound—as the eardrum becomes stiffer and less able to vibrate, it becomes less able to detect sound and transmit it to the brain.

The other reason is a life of noises. Loud noise damages the ears. The damage may be minor, but it is also lasting, and it accumulates. After a lifetime of listening to loud noises, a person's hearing will start to deteriorate. In fact, more and more people are being diagnosed with hearing loss at younger ages than before. This is partly due to more sensitive and reliable tests, which people are undergoing earlier in life, but it's also because of the loudness of modern living, particularly headphones.

Often, however, hearing loss in teenagers is missed. Because it is thought of as a condition, if not fate, or old people, hearing loss is not always even suspected in young people, despite more than half of all people with some form of hearing difficulty having developed it in childhood. Compounding this, many adolescents have difficulty noticing or recognizing hearing loss and adequately conveying that to medical professionals. In principle, young patients will be asked questions designed to find those who may need more objective audiological testing. However, the questions asked are not always useful for patients in that age range, leading to underdiagnosis.

Moreover, noise-induced hearing loss can start as young as age 20. This occurs when the "hair cells" within the ear are damaged by exposure to loud sounds. The hair cells, once destroyed, do not recover, leading to a permanent reduction in auditory acuity. This doesn't merely damage the ability to hear, it actually changes the way the brain processes speech. Not only do sounds not get through as efficiently, when they do get through, they are not processed correctly. However, new medical techniques may hold out hope for recovering hearing ability lost to noise. Researchers have developed a clear picture of the structure of the cells supporting these hair cells, and had some success in repairing them in experimental animals.

Hearing Loss And Your Brain

Most people, as they age, gradually lose their hearing. There are a number of reasons for this. the muscles gradually become stiffer all over, including in the ears. This usually erodes hearing near the top of the pitch range. Additionally, most people are exposed to loud noises—music, trains, highway traffic, even conversation—which can gradually diminish hearing; over the decades, it adds up. While total deafness isn’t common, older people do tend to hear less well than younger people do. In many cases, there is a genetic component to hearing loss as well. Some illnesses (including some that can be prevented by vaccination), medications, or chemical exposure can also cause deafness or diminished hearing ability.

Interestingly, not all noise damages hearing the same way. Research now shows that the time of day at which noise exposure occurs has a bearing on how it affects the ability to hear. It turns out that noise exposure at night results in a greater degree of permanent hearing loss than exposure during the day. Damage to hearing sustained during daytime heals more thoroughly than at night.

A surprising danger of hearing loss is that as a person’s hearing starts to g, their brain becomes smaller. Some brain shrinkage is a normal part of aging, though the effect is not always significant. However, a recent study found that for people with impaired hearing—particularly if left untreated—this loss of brain volume is accelerated. Some of this shrinkage is in the auditory processing regions of the brain. According to MRI scans, however, some of the accelerated shrinkage takes place in the parts of the brain where memory and cognition are located, which makes it a dementia danger.

Another effect of hearing loss on the brain involves mood. Hearing loss—though not total deafness—was associated in a study with higher rates of depression. The correlation was stronger in women than in men. Researchers suspect, however, the hearing loss is not a cause of depression; rather, people who live alone, heavy drinkers, and people with a relatively low educational level were more likely both to have depression and to have suffered some hearing loss.