College students at risk of "hidden" hearing loss
All across the country, college students are getting ready to head back to school after the holiday break. It is well known that close quarters with other students, late nights studying and partying, and lack of sleep can all take a toll on a student’s health. But there is one particular aspect of health that most college students don’t tend to think about: their hearing.
Campus life is noisy
Just a look at a day in the life of a typical college student and you can quickly see why these young people are increasingly at risk. Students walk to and from class with earbuds. After class, the same student might study with earbuds or headphones. Next, our student might head off for a quick workout at the gym; even without earbuds, that workout is likely to expose the student to dangerous decibel levels due to the loud music and ambient noise typical of most gyms. After that, our student might go to a basketball game with friends. Unfortunately the reality is that college basketball game could reach 110 decibels or more. To end his day, our college student goes to a party, where the music is at top volume.
If it sounds like a recipe for disaster, you’re right. Previous studies have shown that as many as 1 in 4 college students have hearing loss in the frequencies necessary to discern speech, and a new study by researchers at Massachusetts Eye And Ear has connected symptoms of difficulty understanding speech amid noise with “hidden hearing loss”, aka cochlear synaptopathy.
The study looked at college students who reported regular exposure to high noise levels. For each subject, researchers measured the health of the auditory nerve and administered a speech-in-noise test. They found a relationship between the electrophysiological measure of the health of the auditory nerve and the performance on the speech-in-noise test. However, among those students who reported the regular use of hearing protection, scores on both the speech-in-noise test and the measure of the health of the auditory nerve were significantly better.
“While hearing sensitivity and the ability to understand speech in quiet environments were the same across all subjects, we saw reduced responses from the auditory nerve in participants exposed to noise on a regular basis and, as expected, that loss was matched with difficulties understanding speech in noisy and reverberating environments,” said Stéphane Maison, PhD, an investigator in the Eaton-Peabody Laboratories at Massachusetts Eye and Ear and assistant professor of otolaryngology at Harvard Medical School.
What is "hidden" hearing loss?
So how is hidden hearing loss different than regular hearing loss? Regular hearing loss, the type of hearing loss often attributed to age or loud noise exposure, is typically caused by damage to the sensory nerve cells. These sensory nerve cells are responsible for changing sound into electrical impulses. Hidden hearing loss, on the other hand, is the result of damage to the connections between the sensory nerve cells and the auditory nerve fibers. What this means is that, while the sensory nerve cells are still doing their job, the electrical signals have difficulty being transferred.
Another difference between regular hearing loss and hidden hearing loss is that hidden hearing loss can occur long before any damage to the sensory cells occurs. It also is harder to diagnose, as it cannot be measured using a standard audiogram. But there is one hint that it may be present: hidden hearing loss tends to manifest itself in difficulty hearing amid noisy environments. Researchers are hoping the results of the study will allow the development of better testing measures that can be used to detect hidden hearing loss.
Hearing loss among young people is not just a problem in the U.S. According to the World Health Organization, 1.1 billion teens and young adults worldwide are currently at risk of hearing loss due to unsafe noise levels.
“Establishing a reliable diagnosis of hidden hearing loss is key to progress in understanding inner ear disease,” said Maison. “Not only may this change the way patients are tested in clinic, but it also opens the door to new research, including understanding the mechanisms underlying a number of hearing impairments such as tinnitus and hyperacusis.”
Hearing loss from noise exposure is entirely preventable.
So what can college students do to protect their hearing for the long term? To start, use headphones and earbuds using the 60/60 rule: 60 percent volume for no longer than 60 minutes at a time. And if you are planning on attending a sporting event or concert, especially one held indoors in a noisy arena, a simple pair of foam earplugs will go a long way in reducing the potential damage to your ears.
If you are having trouble hearing conversation in challenging circumstances, and you think you might be suffering from hidden hearing loss, see a hearing healthcare professional and ask for a screening that goes beyond a standard audiogram. And remember: it is never too early to start taking care of your hearing.