Sometimes domestic cats can suffer a gradual loss of hearing and it can be difficult to tell if your cat is going deaf. Loss of hearing can be caused by middle ear infections, old age, head injury, certain drugs and poisons and a blockage of the ear canal by wax and debris for instance.
Certain antibiotics if administered over a long period of time can damage the auditory nerves which can cause deafness and signs of labyrinthitis (inflammation of the vestibular nerves in the inner ear). The following antibiotics are implicated: streptomycin, gentamicin, neomycin and kanamycin.
When elderly cats suffer a gradual loss of hearing they can retain the ability to hear high-pitched sounds. The sounds are beyond the range of human hearing.
It is possible to make a judgement as to whether your cat is losing her hearing. I’m sure that it helps a lot if you know your cat very well as a close bond will assist in the diagnosis despite the fact that domestic cats compensate so brilliantly. You should spot a subtle change in behavior.
Normal hearing cats swivel their ears to pinpoint the source of the sound and cock their heads towards the sound. If your cat is no longer doing this she may be hard of hearing. Lack of attentiveness is the first sign. Cats are incredibly attentive to sound. Even while snoozing domestic cats swivel their ears to pick up sounds. If she is not doing this it would, I would have thought, be a sign that her hearing might be deficient.
You can make a loud sound while your cat is asleep. If she does not startle and wake up you might presume that there has been a significant loss of hearing. Following on from that, if you suddenly touch a cat who is deaf or hard of hearing she may become startled and at the extreme she may scratch or bite.
Once you know that your cat is deaf, if you want to attract her attention you can stamp on the floor because she will feel the vibrations. Domestic cats use their sense of sight and smell and tactile sensations through their whiskers to compensate for hearing loss. Deaf cats get on very well with other cats.
Domestic cats who are deaf become very sensitive to tiny vibrations made by sounds. They also increase their watchfulness, enabling vision to compensate for loss of hearing. Accordingly, owners of deaf cats should use more visual signals in their exchanges with their cat such as gestures and movements were otherwise they would have spoken to their cat.
This section applies to congenitally deaf cats. Another reasonable way to diagnose your cat for deafness is to presume that there is a much greater chance that she is deaf if she is all-white. White cats are genetically prone to deafness particularly those with blue eyes. Research indicates that out of 125 blue-eyed white cats 54% were deaf. When 60 golden-eyed white cats were examined it was found that 22% had hearing difficulties.
Source: PoC, Desmond Morris and Cat Owner’s Home Veterinary Handbook