Interestingly, there's been some suggestion that hearing loss is not inevitable with age, but is mostly just the accumulation of noise-related hearing loss in a loud industrial society.
I think partly the issue is that how we measure noise doesn't match how noise causes injury. Your cochlea acts as a spiral resonant tube, essentially a "physical FFT," concentrating energy at a particular frequency onto a particular location in the spiral. Too much (local!) energy damages the hair cells, causing conductive hearing loss.
But because we calculate A-weighted decibels by summing all frequencies and then checking if we're above the injury threshold (vs checking whether we exceed the injury threshold at any frequency), using A-weighted decibels can't accurately determine damaging noise levels. If all the energy is concentrated at Middle A it will cause more damage than spreading the energy out across the spectrum, even if the A-weighted decibels come out equal.
It's a somewhat subtle, wrong order-of-operations problem. There's also a separate problem that A-weighting is designed to normalize for perception at various frequencies, not hearing damage.
I've tried searching the literature to find out whether this is either 1)wrong, or 2)generally known within the fields of audiology and occupational hygiene, but so far I've come up empty.
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I recall an HN poster long ago saying how they wore earplugs daily to achieve "super hearing." It occurs to me that all they were doing was actually protecting their ears from damage. :-|
I've tried searching the literature to find out whether this is either 1)wrong, or 2)generally known within the fields of audiology and occupational hygiene, but so far I've come up empty.
FWIW, I've also heard the same, but don't remember where off the top of my head. It's at least potentially true, but the conventional wisdom among acousticians/noise control engineering is that age-related hearing loss is mostly to increasing age rather than external factors.
Oh, I meant about the wrong order-of-operations problem with decibels, which I have never seen anyone talk about. If you've heard of it please let me know.
The links discuss the evidence that hearing loss isn't inevitable with age, including examples of pre-industrial societies with quiet environments that when tested showed no hearing degradation with age.
The controversy seems to be mostly about how much of that effect was caused by good diet vs lack of exposure to loud sounds. I tend to think both are needed to be fully protective, eg to take an extreme example alcohol is known to cause damage to hearing cells even without exposure to loud sounds.
I expect, with apologies to Tolstoy, "All dysfunctional hearing is different, whereas all healthy hearing is the same."
