Many types of conductive hearing loss can be corrected with medical intervention, but what happens when the sound gets through to the inner ear but the message senders in the inner ear themselves are damaged? When this happens it is called sensorineural hearing loss, and it is permanent.
Not Getting Any Younger
One of the most common cause of this type of hearing loss is plain and simple “getting older”. As we grow older our bodies wear and tear and we lose the ability to repair ourselves as efficiently as we did when we were younger.
Hearing loss become more 'normal' the older we get. The RNID tells us that more than 40% of us will have a hearing loss once we get over 50 years of age, and over 70% of us will have a hearing loss once we get over 70 years of age.
Some Things You May Hear TOO well...
When we talked earlier about the inner ear we mentioned the specific places in the cochlea that are sensitive to certain pitches of sound. Some of these places become damaged and don’t send a message to the brain unless a loud noise triggers them off.
So what people with hearing loss often find is that quiet sounds are inaudible but loud sounds are uncomfortable! They will normally say:
“I can hear the traffic but I can’t hear someone talking to me.”
Another complication is that their hearing loss is not regular. In other words it’s not EVERY sound that’s got quieter but only SOME sounds... usually the sounds they need to understand speech! This is because the message senders in the inner ear necessary for speech clarity are closer to the source of the sound, so they are inevitably exposed to more wear and tear. That may be why they go first.
Turn That Racket Down
We live in a noisy world. The sound of traffic, nightclubs, MP3 players, noise at work, roadworks. Repeated exposure to high levels of noise can wear down our hearing. Sometimes the effect is only temporary (perhaps accompanied by ringing), and our hearing may return the following day. But there comes a point when the ears have just had enough: then the damage is permanent.
Of course there are some people who are more at risk from noise-induced hearing loss. These people fall into two categories: those who experience one-off episodes of very loud sound (e.g. gunfire or an explosion); and those who are repeatedly exposed to moderately loud sounds (e.g. factory workers, musicians).
Here are some other examples of people who may have damaged their hearing because of noise:
- War veterans – explosions, guns, aircraft, machinery
- Factory workers & farmers – heavy machinery
- Clubbers – loud music, night clubs, DJs
- Musicians – orchestra members, rock groups, drummers
- Sound Engineers
Unfortunately many people only realise too late the damage that’s been done, yet in many cases they could have protected themselves with ear defenders. In very extreme cases someone has been exposed to an explosion, resulting in the hearing of one ear being more severely damaged than the one furthest away from the blast.
Genetic, Disease or Drug Induced
Some hearing losses are present from birth, either because they are inherited genetically or through exposure to an illness. A mother, for example, who is exposed to German measles or influenza early in pregnancy may have a child with deafness.
Viral infections such as scarlet fever, mumps, meningitis and chicken pox produce toxins that can also damage the inner ear.
Some medicines such as quinine (anti-malarial tablets), gentamicin, neomycin, and kanamycin (certain types of antibiotics) can cause hearing loss. And even aspirin can create a temporary hearing loss, which usually clears up once the aspirin is no longer taken.
Other Causes of Hearing Loss
There are many more causes of hearing loss, both temporary and permanent, including Meniere’s Syndrome, Barotrauma, Tumours and Labyrinthitis. There are also some conditions where no medical reason can be found for a hearing problem - instead it seems to be a psychological problem.
Summary
There are many, many reasons for hearing loss, and very often there are a number of different causes, all interacting with one another, so it's often impossible to pinpoint one specific underlying cause. When a hearing loss cannot be resolved by time or medical intervention, that's when the potential of modern hearing aids can be harnessed.