How does hearing loss happen?
You fall from a tree; you break your arm.
You chain-smoke for 30 years; you get lung cancer.
For some conditions, it’s easy to pinpoint the cause. For hearing loss, however, it’s not always so obvious.
First, a quick recap of our aural anatomy: the outer ear funnels sound into the middle ear, where three tiny bones mechanically amplify and transmit it to the cochlea, or inner ear. The cochlea then transmits the sound signals to the brain via the cochlea nerve.
As with any complicated process, there are vulnerabilities every step of the way. Though hearing loss can stem from the outer ear (e.g. wax build-up or narrowing of the ear canal) or middle ear (e.g. burst eardrum or damage to those three bones), the most common type stems from the cochlea, which contains thousands of microscopic hair cells nestled within a warm bath of cochlear fluid. This sort of hearing loss can be caused by:
- Aging – Over time, the cochlear hair cells that transmit sound signals to the brain can become damaged. Since these hair cells never regrow, this incremental damage slowly decreases our hearing sensitivity.
- Noise – Exposure to loud noises, either acutely (such as an explosion) or chronically (such as working for years around loud equipment or continually listening to loud music) can also damage hair cells. Though the medical profession has brought us awesome names like Exploding Head Syndrome, Maple Syrup Urine Disease, Smoking Stool Syndrome and, my personal favourite, Jumping Frenchmen of Maine, hearing loss caused by noise exposure is unadventurously known as simply Noise-Induced Hearing Loss (NIHL).
- Pretty much anything else – Including stroke, infection, side-effects of medication, head injury or the incessant gnawing of the cochlear nerve by microscopic ear gremlins. Okay, that last one has never been documented – but that doesn’t mean it can’t happen.
Martin Jurek is a Registered Hearing Instrument Practitioner and co-owner of Campbell River Hearing Clinic with his wife Jana. To learn more, visit www.tohear.ca or call 250-914-3200.