What makes a cat deaf?
There is an association with the color of a cat and deafness. Sometimes white cats are deaf either in one ear or both ears. As I have covered this subject in some detail, I won’t duplicate the work here. You can see an article on cat coats white, which also refers to deafness in white cats. This link opens in a new window so you can stay on this page. White cats are sometimes odd-eyed cats (opens in a new window), which are also, fairly frequently, deaf.
Update August 2010: This is a page that covers more ground! I am pleased with this page: Deafness in Cats. It is based on a study.
Update December 2008: I’ve done more work on this subject. This page, deaf cat, looks more at the anatomical issues behind why cats are deaf.
Background: A cat can hear a much wider range of sounds than humans. More accurately, they can hear a wider frequency range of sounds. The frequency of a sound is the number of vibrations of the particles of the medium through which the sound passes. The movement of the particles forms a pressure wave which disturbs the ear drum, which in turn passes this disturbance to the brain via the mechanisms of the inner ear.
The higher the frequency the sharper the sound. A comparison of sounds that can be picked up is as follows:
The cat can then hear both a wider range of sounds and much higher frequency sounds than humans; even substantially higher and wider than a dog. In addition cats have more sensitive ears, estimated to be at least 3 times more acute than human hearing. We should all be aware of this. Noisy households for us are going to be bedlam for a cat and will be destabilizing and make the home less secure and comfortable.
A cat’s ear mechanisms are very similar to ours. There is the outer (ear flap and canal to drum), middle (ear drum and sound transmission mechanisms – the auditory bones) and inner ear (the part that converts sound to electrical signals for the brain).
Deaf cat – some causes:
Old age: Loss of hearing can be due to a number of causes. The classic and most common reason is probably old age and cats are living longer just like humans so there are probably more deaf cats now than in the past. There are probably very few feral cats that are deaf due to old age as almost none live to old age.
Ear canal blockages: Ear wax can effect cats as it does humans. Ear wax is designed to protect the ear so if there is too much to the point where hearing is impaired, there will, in my opinion, be an underlying cause. Fungus/yeast infections can in my view cause excessive production of ear wax in humans and this may also be the case for cats. The yeast triggers an immune response, which in turn causes an increased production of wax (this is my personal theory supported by personal evidence). Vets treat fungus and yeast infections with drugs. An effective over the counter product for humans is a shampoo containing ketoconazole.
Other blockages can be caused by debris entering the ear canal and/or exacerbated by or perhaps caused by cat ear mites (opens in a new window).
Middle ear infection: In medical terms this is called “Otitis Media”. These are uncommon. The infection is usually an extension of an infection elsewhere, for example the outer ear or mouth or sinus infections that have migrated to the inner ear. These are painful and urgent Veterinarian diagnosis and treatment will be needed.
Drugs: Apparently long term us of antibiotic drugs can cause damage to auditory nerves.
What can we do about it if we have a deaf cat companion?
One advantage of such fantastic hearing is that when it begins to fade due to old age it is still going to be as good as ours. If a cat’s hearing is at 20% of its previous level (one fifth as good), it will still be about half as good as ours at peak level. So a great reduction still leaves functional hearing.
It may not be readily apparent that we live with a deaf cat or partially deaf cat as cats can compensate well with their acute sense of smell, their sight and their general sense of awareness. They can also use their whiskers to good effect. Cat whiskers are so sensitive they can sense air vibrations and are used to help a cat find her way around in the dark.
However, a cat’s ears are usually very active. They can swivel to focus on the source of the sound. If they aren’t as active as they should be this would indicate the onset of deafness to me. Although a cat can look one way while the ears are pointed in another direction, they will normally look towards the source of sound (ears and eyes working together). This can be tested. My cat responds to the sound of her name said by me in certain and always the same way. She responds to this (not always!) normally by her ears swiveling and her head turning. If there was no reaction on a consistent level something would be wrong.
A more severe test would be to make a noise while your cat slept. If she remained asleep you’ve got the answer. However, cats can feel vibrations far better than us and sleep lightly remaining alert, so you’ll have to walk carefully when doing this test.
A deaf cat should cope pretty well provided we accommodate the deafness and are sensitive to it. It is all about common sense and respect.
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