What Causes Hearing Loss?
What causes hearing loss? Let’s start with prescription drugs – certain chemotherapy drugs and diuretics , antibiotics like dihydrostreptomycin and erythromycin are all ototoxic, poisonous to the inner ear. Even high doses of aspirin can damage the inner ear.
Medical conditions including brain lesions, diseases of the ear that cause deformities, and otitis media (middle ear infection) can result in impaired hearing. Children frequently suffer ear aches resulting from otitis media. If the infection is bad enough to rupture the eardrum, the permanent scar tissue after it heals makes the eardrum abnormally rigid. That results in conductive hearing loss. Sound is not conducted to the inner ear as freely as before the infection.
But, the greatest cause by far is loud noise. Our world is simply to loud for the human ear. Loud sounds cause sensory-neural damage to the inner ear. This means that the hearing nerves, known as “hair cells” in the inner have been damaged by loud sound. The snail shell looking structure called the cochlea contains these sensitive hair cells floating in fluid. If sound vibrations are intense enough, the hair cells will break and decay, rendering them less sensitive to certain frequencies.
Unfortunately, it is the hair cells which feel the high frequencies that get damaged the most. These high frequencies correspond to the consonants – the t, p s, th, c, ch, etc. Imagine hearing mostly vowels-a, e ,i, o, u. This just sounds like noise without the definition given by the consonants. That is what those with high frequency hearing loss experience every day. They complain about hearing without understanding. “People mumble so much!”, they say because they barely hear the consonants. Fish may sound like dish, comb may sound like home.
This can be either funny or embarrassing. One of my patients, Gertrude still laughs about the time when her husband Ted misunderstood her. Being an avid bird watcher, she excitedly told Ted about the grosbeak bird she just saw. He replied with, “That’ll be fine.” He thought she wanted roast beef for dinner!
Inner ear nerve damage is permanent. No medical treatment has been developed to heal it. The good news is, digital amplification provided by hearing aids can make a world of difference for the hearing impaired, regardless of the stage of hearing loss. If the hearing aids are properly programmed and fitted, they can be worn all day comfortably. They can bring us back into the world of sound.