Deafness is often difficult to assess accurately, mainly because cats are not able to tell us when they have trouble hearing. Usually, it is their failure to obey commands or respond to familiar noises that first alert cat owners to a deafness problem.
When cat begins to go deaf the process is normally a gradual one. You will probably not be able to tell that your cat is going deaf until they have lost most of their hearing. Most pet owners who discover that their cat has gone deaf have noticed for awhile that something about their pet seemed a little off, but they couldn’t quite put their finger on what it could be.
Deafness in cats can be of two kinds: conductive or sensorineural. If sounds cannot travel properly in the external or middle ear, the problem is said to be conductive. If the deafness is sensorineural, the inner ear is involved and deafness is usually total.
Diagnoses of deafness in cats can usually be made by observation but your veterinarian 1can definitively diagnose hearing loss through the Brainstem Auditory Evoked Response (BAER) test. The procedure is painless and takes 10-15 minutes to administer.