Evidence of ‘Hidden Hearing Loss’ in College-age Subjects
According to a study out of the Massachusetts Eye and Ear Infirmary and published in PLOS ONE, researchers have finally linked symptoms of difficulty understanding speech in noisy environments with evidence of cochlear synaptopathy, a condition known as ‘hidden hearing loss’, in college-age human subjects with normal hearing sensitivity.
The study revealed a significant correlation between performance on a speech-in-noise test and an electrophysiological measure of the health of the auditory nerve. They also saw significantly better scores on both tests among subjects who regularly wore hearing protection when exposed to loud sounds.
“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,” one researcher said.
While regular hearing loss is caused by noise or aging and typically arises from damage to the sensory cells of the inner ear (or cochlea), ‘hidden hearing loss’ refers to synaptopathy, or damage to the connections between the auditory nerve fibers and the sensory cells, a type of damage which happens well before the loss of the sensory cells themselves. Loss of these connections likely contributes to difficulties understanding speech in challenging listening environments, and may also be important in the generation of tinnitus (ringing in the ears) and/or hyperacusis (increased sensitivity to sound).
Another researcher noted, “Establishing a reliable diagnosis of hidden hearing loss is key to progress in understanding inner ear disease. 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.”
Razi Berry, Founder and Publisher of Naturopathic Doctor News & Review (ndnr.com) and NaturalPath (thenatpath.com), has spent the last decade as a natural medicine advocate and marketing whiz. She has galvanized and supported the naturopathic community, bringing a higher quality of healthcare to millions of North Americans through her publications. A self-proclaimed health-food junkie and mother of two; she loves all things nature, is obsessed with organic gardening, growing fruit trees (not easy in Phoenix), laughing until she snorts, and homeschooling. She is a little bit crunchy and yes, that is her real name.