By Christie Long
Nearly 100 breeds of dogs are recognized to have congenital deafness, meaning a defect that has been present since birth.
Dalmatians, bull terriers and Australian cattle dogs are overrepresented. Cats can be deaf from birth but exactly which breeds are predisposed is less understood. Deafness in either species seems to be linked with white coats and/or blue eyes but not always.
An animal can be deaf in one or both ears, but we often don’t pick up on any deficiency in those that are deaf in just one ear.
Deafness in dogs is more quickly recognizable since we expect them to respond to the sound of our voice or loud noises. Since humans as well as the world at large are frequently ignored by cats, it’s a little tougher to tell when they can’t hear. In either case, deaf animals should never be bred, since the trait will be passed down to subsequent generations.
The only completely accurate way to determine if a dog is deaf in one or both ears is to perform a Brainstem Auditory Evoked Response (BAER) hearing test. The test uses a computer to record the electrical activity of the brain in response to sound stimulation. Since the BAER test was developed for use in humans, it does not measure the full range of canine hearing. But enough data can be gathered to determine if the dog can hear within the normal human range.
The CSU Veterinary Teaching Hospital can perform this test to determine if an animal is deaf in one or both ears.
Dogs that are deaf from birth can be trained to respond to hand signals and still be wonderful pets. The trick to training them is getting their attention so they can look to you for a signal. Vibrating collars often are used to train these animals. The dog is taught that when it feels a vibration from the collar it should look to its owner.
Dogs and cats can have acquired deafness, meaning they become deaf later in life. Causes of acquired deafness include chronic ear infections, noise trauma, certain drugs used in topical ear preparations, geriatric changes and rarely general anesthesia. Dogs with acquired deafness also can be trained to respond to hand signals.
It’s important to remember deaf animals need to be protected from dangers that would give auditory cues to a hearing animal, such as oncoming cars. Children need to be instructed on how to approach a deaf animal so they do not startle it.
The website lsu.edu/deafness/deaf.htm is maintained by the school of veterinary medicine at Louisiana State University and is an excellent resource about congenital and acquired deafness in dogs and cats.
Helpful tips on training deaf dogs can be found at www.deafdogs.com.
Christie Long is a veterinarian at the VCA Animal Hospital in Fort Collins, CO. Long left her job in software sales in 2000 to travel for 13 months. Along the way, she was touched by the plight of the animals she saw and somewhere in the Nepalese Himalayas she vowed to return to school to become a veterinarian. While she often finds end-of-life situations heart-wrenching, she considers herself blessed to be called upon as a trusted advisor to families during difficult times. Dr. Long’s family includes her husband and travel partner, Wiley, their 5-year-old son, Wiley IV, their dogs Pancake and Gizmo and cats Sneaky and Sidh.