Some of the ear canal infections can go ahead with such swelling that the canal gets fully obstructed often the swollen skin also discharges infectious liquid, which may leave even redness and rhaghades visible at the outer ear.
In these cases we observe also a muffled hearing. But the worst is that it goes along with unbearable pain and if certain germs are involved, with erosions of the tympanic membrane that may lead to holes in the ear drum.
Severe pain of the ear may also come from arthritis of the temporomandibular joint. This joint is forming a part of the bony wall of the ear canal and the patient cannot distinguish where the origin of the pain may be.
If a muffled hearing is not due to impacted wax or swelling of the ear canal, it comes in most of the cases from a disturbance in the middle ear.
The middle ear is the cavity behind the ear drum. Like any cavity in our body it needs to be continuously ventilated and its pressure needs to be equalized with the ambient pressure.
There is a tube which connects the middle ear with the area at the inner end of the nose, the Eustachian tube. When we swallow or yawn we can actively open the tube a little bit. We can also close our nose with the hand and press air upwards into the Eustachian tube until it pops in the middle ear.
When our body is exposed to ambient pressure changes for example when we go diving or when we fly by plane or even when we are in the mountains, this may be necessary to equalize the pressure in the middle ear. Some people are so sensitive that even in elevators they need to actively let their eardrum pop when they equalize the ear pressure with the air pressure.
If this process for some reason does not work, then we get the problem of a vacuum that develops in the middle ear and sucks the tympanic membrane inwards. The tympanic membrane can be compared to the membrane of a loud speaker. It can be easily understand that such a vacuum gives us a feeling of muffled sound in the respective ear. Many people know such feeling from flying.
If we don’t manage to get rid of the vacuum it will eventually extract liquid from the tissue of the middle ear. People often hear that they have water in the ear and wonder how it could get inside and why it won’t just run out. This picture represents in most of the cases such liquid which has developed from the vacuum in the middle ear.
The liquid is a perfect boullion for germs to settle and can easily lead to a middle ear infection. Apart from that it definitely muffles the hearing a lot, by about 30 dB.
Dr. Marc Mueller