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Updated: Jul 8th, 2008 - 04:55:05 |
Just like humans and other animals with the ability to hear, dogs can suffer hearing loss. They can be born deaf or become deaf because of hereditary factors, or be robbed of normal hearing by infection, injury, loud noises or old age. Deafness can be present in one or both ears, and some breeds like Dalmatians, as well as other white dogs of mixed or pure breeds, are more prone to deafness. Some breeders, breed clubs and even veterinarians advocate euthanasia for deaf dogs. As a result, many dogs are condemned to death but the lives of deaf dogs can be as full, safe and healthy as those of dogs with normal hearing.
One of the most interesting aspects of congenital deafness is the link between coat color and deafness. The genetics are complicated and many factors may combine to result in a dog with a lot of white in its coat. Most dogs that appear to be solid or mostly white have pigmented skin along with black noses and eye rings. However, if there is unpigmented skin in the inner ear (which can’t be seen by looking at any visible part of a dog’s ear) the nerve endings atrophy and die off in the first two weeks of life, resulting in a deaf puppy. A fascinating discussion about the ways genes combine to produce various color combinations and patterns in dogs is at the Deaf Dog Education Action Fund (DDEAF) website. (www.deafdogs.org)
Deafness in dogs may not be as obvious as you might think. Deaf puppies may play more roughly than their littermates because they can’t hear the squeals of their siblings that teach hearing dogs to inhibit sharp nips and rough play. Dogs with hearing loss in one ear (unilateral deafness) may compensate so well that their deafness is nearly hidden; one clue is that the unilaterally deaf dog may appear confused about where a sound is coming from, or actually look in the opposite direction trying to locate it. I adopted Sylvia, a black Greyhound/Lab mix, from a high kill shelter when she was 11-12 years old. She settled right in to our family of two humans, four other dogs and two cats and was with us for weeks before we realized that she was completely deaf. We don’t know the cause of her deafness or how long she had coped with silence, but I suspect a combination of having possibly been a gun dog (common in the Midwest for this breed mix) and advanced age. She was so adept at picking up and interpreting visual cues from her pack mates and the environment – even “hearing” the vibrations of loudly clapping hands behind her – that she kept her secret well.
DDEAF www.deafdogs.org) suggests tests for hearing loss you can do at home:
• Jangle keys, a rattle or a can of coins
• Squeak a toy (be sure that air from the toy doesn't hit the dog - try it behind your back)
• Call your dog in a normal voice - try yelling
• Clap your hands (you should be far enough away so that he doesn't feel air movement)
• Whistle or (if you're musically challenged) blow a whistle
• Turn on a vacuum cleaner (be sure it's far enough away from the dog so that the vibrations or airflow don't reach him)
• Bang two pots together (be careful of air vibrations reaching your dog)
• Ring a bell or have someone ring your telephone or doorbell
If the dog is deaf on just one side, you will get different results depending on which side it is sleeping on or from what angle the sound comes. According to DDEAF, if your dog doesn't hear normal sounds at normal volumes, chances are that it is deaf. The only way to know for sure is with a BAER (pronounced “bear”) test - Brainstem Auditory Evoked Response. A BAER test uses a computer to record electrical brain activity in response to sound stimulation, similar to tests used on infants. BAER testing is not widely available and can be expensive, so home testing may be sufficient to assess hearing for practical purposes.
A number of myths about deaf dogs can make potential adopters wary. Among the most common:
Deaf dogs are vulnerable to injury because they cannot hear on-coming cars. So is any dog allowed to roam in traffic. A deaf dog, properly leashed or confined, is in no more danger than a hearing dog.
Deaf dogs can be easily startled into aggressive responses and should not be kept around children. The truth is, a well-socialized deaf dog is as safe around children as any other dog. And of course, small children should always be supervised around any dog for the dog’s protection as well as the children’s.
Deaf dogs are hard to train. The same variations in trainability among all dogs apply to deaf dogs as well. Deaf dogs can as easily learn to respond to hand signals as hearing dogs can to voice commands.
Deaf dogs must live with a hearing dog to function well. The DDEAF says this myth is perhaps the most damaging to rescue dogs because potential adopters who may be willing to take on one dog hesitate to adopt two. In fact, deaf dogs do as well as other dogs in single dog homes but also adapt well when adopted into a family that already includes a hearing or deaf dog.
One day, I watched Sylvia sit unmoving, staring intently at the ground for nearly 15 minutes while the other dogs played around her. Because of her age, I feared she was sick or having a seizure. Suddenly, in a pouncing motion, she leapt at a spot and started digging furiously. In seconds, she emerged with a mole, which she examined thoroughly and then released. Her evident sensitivity to vibrations and her ability to focus undistracted by noise made Sylvia the superior mole hunter of the pack; proof positive that deaf dogs can not only function but can also excel.
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