Deafness refers to the lack (or loss) of an animal's ability to hear -- this can either be complete or partial loss. If the dog is deaf at birth (congenital), it will be very apparent to you at a young age. More than 30 breeds of dogs have a known susceptibility for deafness, including the Australian shepherd, Boston terrier, cocker spaniel, Dalmatian, German shepherd, Jack Russell terrier, Maltese, toy and miniature poodle, and West Highland white terrier. Typically, it is more common in senior dogs.
The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the petMD health library.
A complete history of the dog, including any drugs that may have damaged the ear or caused a chronic ear disease, is completed by the veterinarian. Early age onset usually suggests birth defects (congenital causes) in predisposed breeds. On the other hand, brain disease is a slow progressive disease of the cerebral cortex, usually caused by senility or cancer -- making the brain not able to register what the ear can hear. Bacterial cultures and hearing tests, as well as sensitivity testing of the ear canal, may also used to diagnose the underlying condition.