Hidden Hearing Loss:
Why “Normal” Test Results May Not Mean Normal Hearing
“The discovery of something termed “hidden hearing loss” has hearing healthcare professionals strongly encouraging people to get tested more FrEquEntLy AnD DIsCussInG tHEIr DIffiCuLtIEs wItH their Hearing Professional even if results come back “normal.”
Trouble hearing in noisy backgrounds? Identifying hearing loss is the first step to treating it, but a standard audiogram may not detect it and can produce normal hearing test results. This leaves many Canadians knowing they have a hearing issue, but feeling like they can’t do anything about it, but new insights into what is termed “hidden hearing loss” now has hearing healthcare professionals strongly encouraging people to get tested more frequently and discuss their difficulties with their Hearing Professional even if results come back “normal”. These people may be at an increased risk of developing permanent hearing loss and should be continually monitored and counselled on the importance of hearing protection and conservation. The Science behind Hearing Loss
Sound and your brain are like two people who speak a different language. Sound speaks in vibrations and our brains speak in signals. In our inner ear are thousands of tiny hair cells that act as language translators. When sound travels into our ear, these sensitive hair cells translate the sound vibrations into signals that our brains can understand. Our auditory nerve fibers then act as messengers that send the signals to our brains. When we complain that we can hear sounds but cannot understand them, this usually suggests damage to our hair cells or our auditory nerve fibers.
Long before our hair cells or auditory nerves are damaged, there can be a communication breakdown between the two, and this is known as hidden hearing loss.
A regular audiogram cannot identify hidden hearing loss, but for the first time, researchers from the Massachusetts Eye and Ear Infirmary have linked difficulty understanding speech in noisy environments to hidden hearing loss.
The subjects of their study were young adults who may regularly overexpose their ears to loud noise levels. There was a significant correlation between their performances on a speech-in-noise test and the health of their auditory nerves. Those who regularly wore hearing protection when exposed to loud sounds performed better on the test than those who did not, even though all the subjects had normal hearing sensitivity.
“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 Dr. Maison, an investigator in the Eaton Peabody Laboratories at Mass. Eye and Ear and Assistant Professor of Otolaryngology at Harvard Medical School.
Researchers suspect that the noise-induced, damaged connection between our hair cells and auditory nerves could be linked to the generation of tinnitus (ringing in the ear) and/or hyperacusis (increased sensitivity to sound.) This new discovery could revolutionize hearing testing by allowing hearing professionals to detect hearing loss earlier than ever before.
This is great news, because according to Statistics Canada, one in five Canadians have some degree of hearing loss. This increases to 47% for Canadians over the age of 60. It is now recommended to get a baseline hearing test for anyone who is experiencing signs of hidden hearing loss or who is 60 years of age or older. If you suspect you have hearing loss, book a free hearing test today by calling 1-888-440-0268 to schedule your appointment.