Dogs with acquired deafness are born with the capability of developing and maintaining normal hearing, but hearing is lost as the animal ages. Acquired deafness is not common to any one breed, but rather, is seen in individuals of all breeds. It is usually the result of damage to the ear components such as the eardrum, middle or inner ear structures, and nerves. Diseases such as canine distemper is a common cause of ear damage. Trauma to the ear areas of the head may result in hearing impairment. Various drugs including the Aminoglycoside
antibiotics can be toxic to the ear structures and cause deafness. Aminoglycoside antibiotics such as Gentamicin, Neomycin, and Kanamycin should not be used except under strict veterinary supervision. High doses and/or lengthy treatments with these antibiotics should be avoided.
In the authors' experience, the most common cause of acquired deafness in dogs is simply the result of untreated otitis externa and otitis interna. Mild ear infections left untreated always have the potential to cause hearing impairment.
Regardless of cause, most dogs with acquired deafness are not totally deaf, but rather have varying degrees of hearing impairment.
What are the risks?
Dogs with acquired deafness do not all become deaf to the same degree. Some dogs have only a partial hearing loss, in fact, it may not be noticeable to the owner. Others have severe hearing loss. They can be more prone to injuries, since they cannot hear commands or objects coming towards them.
What is the management?
There is no treatment for acquired deafness. Fortunately, most dogs cope very well with a hearing disability. Individuals can be taught hand signals, and the use of lights can be used to signal dogs as well. The book, Deaf Dog: A Book of Advice, Facts and Experiences about Canine Deafness by Susan Cope Becker may provide the owner of a deaf dog with valuable information.