by Neil Bauman, Ph.D.
A lady wrote:
At certain times, the sound in my left ear will suddenly surge to such a level that it is intolerable. This happens often at the end of a meal. Also, when I made a trip this summer, it happened in the plane on every leg of the trip.
When sound levels suddenly change when eating or flying, often the cause is your Eustachian tubes not properly regulating the air pressure in your middle ears.
One of the functions of your Eustachian tubes is to keep the air pressure in your middle ear (an air-filled cavity) at the same pressure as the outside air pressure. Normally, your Eustachian tubes are closed, but whenever you swallow or yawn, your Eustachian tubes open momentarily to equalize the air pressure.
However, if your Eustachian tubes are not working properly for some reason, or if they get clogged up, for example, from a cold or virus, when you swallow or yawn, the mucous and “gunk” in them prevents the air from freely flowing through them. The result is that either you have lower or high pressure in your middle ears than the outside atmosphere.
If your middle ear has reduced air pressure inside it, then the ear drum is sucked in more than usual. Thus, any sound vibrating it would really shake the middle ear bones since they are now much closer to the eardrum than usual. The result is much louder sounds than normal.
By the same token, if there was increased air pressure in the middle ear, the ear drum would be slightly pushed out. Thus, it would not make contact as good a contact with the middle ear bones as it normally would. The result is reduced hearing.
You often notice this latter condition when you are flying (taking off) or going up a hill. Sounds get fainter and fainter until you swallow or yawn and let the air pressure equalize. When you do this, suddenly the sounds return to normal. The change in volume can be considerable.
For example, when I am flying, if I deliberately don’t yawn or swallow, as the plane ascends enough pressure can build up in my middle ears so I can’t even hear the sound of the jets any more. Swallowing brings the sound back with a bang!
The good news is that whenever you swallow or yawn and your Eustachian tubes finally clear themselves, your hearing should return to your normal levels.