Recommend classical Music

[KvHagedorn]

Loss of hearing is not an effect of age.. it's an effect of wear. I saw an interesting program about this where they went to Africa to study the Masai of Kenya. There they found that men in their 70s had hearing that was still as good as Westerners who were in their teens. The reason being that they were not exposed to the daily barrage of noise pollution that we are. I would expect to find similar results among the Amish.

[az]

Yes, it's about time we do something about noise pollution.

AZ

[Brian Ellis]

KvH

I agree that loss of hearing is a result of overexposure to noise. A loss of perception of high frequencies is due to a sclerotic thickening of the resonant receptors in the cochlea and is age-related, but not necessarily exclusively.

[Brian R.]

The results from the Masai study may indicate that age-related hearing loss is genetic in nature.

[Muad'Dib]

KvH - atrophy to the auditory nerve is also a result of age and causes hearing loss to a certain extent (obviously this is dependent on the genetics of the individual as Brian R. suggests).

The genetic aspects of hearing loss are quite clear when looking at various syndromes in which hearing loss is expressed - for example Alport Syndrome.

Brian Ellis - Thanks for the explanation. I did not know he was Mormon I still do not know what F&M Audiometry entails though (in terms of testing procedure). All I'm familiar with is variations of Hughson & Westlake and Bekesey audiometry as well as a couple others which are not used clinically (whose names I'm currently forgetting). Oh, and I've heard the effects you're refering too. There is a tape that demonstrates it quite well made by Phonak I believe - it involves more than simply the 10K - 20K range, but demonstrates your point quite well (I've also heard that region dropped by EQ's).

[Brian Ellis]

F & M audiometry is the simple method that these gentlemen used, 14 years before the first commercial audiometer was invented. A signal generator providing a calibrated variable amplitude sine wave, a single headphone, a calibrated frequency response curve of the headphone. The threshold of hearing is determined at each chosen frequency and corrected for the headphone response. The curve is drawn by hand. It's as simple as that. In my case, my +30 dB point (over mid-range) has shifted 5 kHz to the left over the last 50 years (I no longer have any instrumentation, and this was the result about 5 years ago, when I last tried it on myself). Within the accuracy of empirical errors, my mid-frequencies are down about 10 dB in my left ear and nearly 20 dB in my right ear, as well. This is more difficult to calibrate, as it depends on the ability of the calibrating microphone to translate the sound into air pressure variations with the headphone stuck over a simulated ear. I'm not sure how F&M did this: all I know was their work was directed to getting maximum intelligibilty over a telephone, using a carbon microphone and a moving iron diaphragm earpiece.

[Muad'Dib]

Brian Ellis, while I find this conversation fascinating, I'm not entirely sure everyone else does so. I see you are not available for PM's or email through the board. Please email me at mitzo@comcast.net.

Thanks