Divers, beware of your 6000Hz frequency !

We highlight here the results of a study conducted on 32 divers in a diving club in the Paris area.

First remark :

The main damage to the inner ear is the 6000Hz and it affects more freedivers than scuba divers. Indeed, on the audiometric curve of 32 tested divers :

• 87% of scuba divers have a specific damage of the 6000Hz frequency ;
• This impairment affects 95% of pure freedivers and scuba divers ;
• Less than 50% of all divers have a concomitant impairment of the 4000Hz and 8000Hz.

Why this specific attack of the 6000Hz ?

Because anatomically the oval window, where the stapes are located, is opposite the 6000Hz area of the cochlea (snail-shell shaped and seat of the auditory cells). Pressure blows from the stapes during repeated Valsalvas will damage this frequency first. In the same way, sound aggressions will damage this frequency in priority. Then, by extension in oil spot the close frequencies will be reached (4000Hz and 8000Hz).

Why are freedivers the most affected ?

During a descent, the compensation in apnea is more violent because the lungs are crushed as the descent proceeds. The Vasalva leads to consistent and repeated blows on the stirrup. This piston stroke, which mainly affects the inner ear with a participation of the middle ear, is mentioned in our article on the diver’s ear.

Corollary :

Always ask your ENT to measure this frequency which is sometimes shunted by ignorance (it has been said for a long time that the first frequency affected by sound or pressure trauma (which amounts to the same thing in terms of injuries) was 4000Hz! Habits die hard, whereas repeated examinations prove that this is not the case. However, to detect early an attack of the 6000Hz allows much earlier preventive measures for the future of its ear (we have only two during our long life).

Second remark :

Is there a bias in this statement ?

If we consider that sound traumas accumulate during a lifetime and that the lesions attributable to them are the same, it is logical to wonder if it is only diving that harms the ear. During a systematic hearing test in a young adult with no previous history, isolated damage to the 6000Hz or other high frequencies (4000Hz, 8000Hz) remains quite rare.

It should be noted that for 25% of the apneists followed, the auditory impairment of the 6000Hz did not exist at the time of the first examination and is present in less than 3 years.

If we have to incriminate age in these specific lesions of the 6000 Hz, then it would be logical to see the number of divers affected increase with age. However, for freedivers who also practice scuba diving as well as for scuba divers only, there is no over-representation of the number of affected divers in the age groups above 55 years. This allows us to conclude, without too much risk of being mistaken, that it is neither the age nor the seniority of the divers that is responsible for these injuries (we can arbitrarily suppose that the older divers have been diving for longer than the younger ones) but rather the repeated pressure aggression favored by the violent Valsalvas, especially among the freedivers.

This sketch of a study, which can be refined with time, reveals an essential fact: the compensation of the ears by the Valsalva must be proscribed and the Frenzel method must be taught/practiced systematically.

In conclusion :

• Stop the Valsalvas and prefer the Frenzel and the Voluntary Tubal Béances, in order to avoid the repeated blows of the stirrup ;
• Prefer slow descents with always a time advance in the balancing of the ears (ideally one should never be in pain) ;
• Classically, do not dive if you have a cold.

In a word, be attentive to your ear, a crucial element that will allow you to avoid serious irreversible damage.

© Alex Voyer for all the pictures of the article

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