|Print |Text Size: |||
There’s a brief moment in Mike Nichols’ iconic 1967 movie, The Graduate, that helps me imagine what life is like for my 15-year-old Corgi, Edgar, who has lost most of his hearing. Early in the film, Benjamin Braddock, the eponymous graduate, enters a pool party given by his parents in his honor, wearing full SCUBA gear. Wellmeaning faces from his past float up in succession, each one with advice about what he should do with his life, but, while he can see their mouths moving and read their facial expressions, all he can hear inside the diving mask is the sound of his own breathing.
Every now and then, I look Edgar straight in the eye and say, as helpfully as I possibly can, “Plastics.” That is the advice given to Benjamin by the soonto- be-cuckolded Mr. Robinson about a possible career path. No one ever laughs at my jokes, so Edgar’s blank look is not new, but it makes me feel as though I am still communicating with him even though he cannot hear.
It might seem petty to worry about a little deafness when Edgar is in otherwise perfect health. But I realized that his deafness was a barrier to our bond, and that I felt as estranged from him as he undoubtedly did from me. He had never come when he was called, so that was nothing new. But suddenly he looked away when I said the various trigger words — “Let’s go for a walk,” “Do you want a treat?” “Do you want to ride in the car?” — that used to cause him to cock his head from side to side in a manner that made it clear we were communicating. Suddenly, he was silent during birthday parties, when in the past, his exuberant baritone rang out above all the other voices during the Happy Birthday song.
Dogs’ hearing mechanism is basically the same as that of humans, and they experience hearing loss for many of the same reasons: they can be congenitally deaf (deaf since birth), or they can acquire deafness due to having dirt, wax, ear mites or other foreign bodies in the ear; an infection or inflammation of the ear canal; trauma to the head; noise trauma; exposure to certain antibiotics or other drugs; or old age. I do not know when or why Edgar lost his hearing; part of it was undoubtedly just normal aging process. But he also had an ongoing skin infection that extended into his ears, which I treated with antibiotics, either of which can cause hearing loss. His hearing seemed to have deteriorated overnight, but most likely, it was a gradual process that I didn’t notice until he exhibited some of the more obvious symptoms: pacing around looking for his people, suffering obvious distress at being left alone, exhibiting a pronounced startle response at being touched while he was asleep.
“In hearing, as in most other things, dogs are very adaptive and good at compensating,” says Colette Williams of the University of California, Davis, Pritchard Veterinary Medical Teaching Hospital. Williams has been an electro- diagnostician at UCD for 29 years. Among many other tests that she conducts, she assesses animals for hearing loss using brainstem auditory evoked response (BAER) technology. Many seeking her expertise are breeders, who use BAER to identify congenital deafness in their puppies.
If a puppy is found to be bilaterally deaf (deaf in both ears), breeders have a difficult decision to make: euthanize that puppy or let it go as a pet. Those who favor euthanasia point out that many deaf dogs end up in shelters because of the challenges in training them. Also, deaf dogs often get hit by cars, and they can be snappy when they are startled when sleeping, which gives the breed a bad name.
Colette Williams has tested thousands of dogs and has owned two deaf dogs of her own. One of her dogs, a bilaterally deaf-from-birth Dalmatian, learned hand signals that Williams and her son made up. “The key was consistency, and rewarding him with treats,” she says. “I had a hearing dog at the time, and he was harder to train than the deaf dog.” Hearing dogs often aid a deaf dog, Williams points out. They give social cues and can help with training. Williams trained the hearing dog to wake the deaf dog so she didn’t have to worry about the deaf dog biting her young son if he touched the dog while he was sleeping.
Deaf dogs can be marvelously adaptable and inventive. “Dogs are good at using their other senses,” says Williams. “My deaf dog knew where every cat in the neighborhood was. When we walked, he would scan from side to side, taking in everything.”
Like Edgar has had to do, Williams’ deaf dog accepted his condition and got on with life. “Dogs don’t have the self-pity that a lot of people have,” she says.
Seattle-area dog trainer Diane Rich, who has worked with numerous deaf dogs over the past 25 years, points out the importance of developing other modes of communication regardless of whether your dog is deaf or has tip-top hearing. She teaches people to use a combination of body language, hand signals and auditory cues. That way, if the dog loses hearing in old age, he won’t feel quite as isolated. “People want to keep up communication with an older dog,” says Rich. “It takes a lot of patience. You have to learn how to communicate differently, not just verbally.” She also recommends teaching all puppies a “watch” command in addition to the usual commands. Hold some alluring food near the dog’s nose and slowly bring it to your eye level, maintaining eye contact with the dog. Say “Watch” or “Look.” Work on “fading the lure,” and eventually, you’ll be able to just point to your eye and have the dog’s full attention. “Dogs use an array of body language already,” says Rich. “People need to be able to use their own body language to communicate with their dog.”
While many people teach their dogs American Sign Language, any hand signal will do, as long as you’re consistent. “There’s no ceiling to how many words or signs a dog can learn,” says Rich. “They can learn as long as they have a pulse and you have motivation and patience. If you make training fun, they’re going to love learning, and it’s going to cement your bond.” She points out that it’s not true that you can’t teach an old dog new tricks: sometimes it’s easier to train older dogs because they have longer attention spans.
Further, she recommends taking a matter-of-fact approach to your deaf dog’s disability. “Dogs aren’t saddled with ego,” she says. “If we pity them, we can create a situation where the dog may either shut down or act out because they think they did something wrong to make us feel bad. If you act like the disability isn’t a big deal, dogs will respond like it’s not a big deal.”
And so Edgar and I continue together into (in my case) middle age and (in his case) senescence. Taking care of him is a lot of work, but the truth is that I am no bargain either. He is very accepting of the ways in which I am not perfect, and, in turn, I am accepting of his increasing physical limitations. Every day, we practice the hand signals we learned in puppy class 15 years ago, which he still remembers: come, sit, stay, down, good boy. I smile a lot and pat him while giving the “thumbs up” sign when he does something well. I continue to tell him my jokes and he continues to give me a blank look, just like he always has. On every birthday, I bark and howl and yelp when people sing the Happy Birthday song, in honor of the joy his “singing” has given me over the years.
Though he requires a lot of extra care for all his special needs, it is care I am happy to provide in gratitude for the happiness he has brought me. In short, even though he has lost his hearing, arthritis has slowed him down, he sleeps most of the day and cannot participate fully in all of our old antics, he is still my best friend, and encroaching old age will never change that. Because — as every creaky, long-in-the-tooth, middle-aged woman and failing, deaf, 15-year old dog know — love is blind.
The BAER Test
BAER (brainstem auditory evoked response) is a diagnostic test for hearing whereby a dog is fitted with a sound source in the form of earphones with foam inserts that extend into the ear. The device emits a sound and the response is detected by tiny electrodes that have been placed at specific sites on the dog’s head and shoulders. The BAER detects electrical activity in the cochlea of the ear as well as in the auditory pathways of the brain, much like an EKG detects electrical activity in the heart. The resulting waveform definitively shows the extent and degree of a dog’s hearing loss and is used to evaluate a dog’s hearing status. The procedure is painless, but occasionally dogs will object to wearing earphones and being lightly restrained; in extreme cases they are muzzled or sedated, though this is rarely necessary. Results are available on the spot.
While curious pet owners sometimes seek confirmation of a hunch that their dog is deaf, BAER testing is used routinely by breeders, primarily those whose breeds are susceptible to congenital deafness. Coat-color-related deafness is associated with some white-coated and merle breeds, such as Dalmatians and Australian Shepherds. (To find out which breeds are most affected, see Louisiana State University’s Dr. George M. Strain’s comprehensive list .)
Inside the ear, the organ of Corti includes a layer of cells, the stria vascularis. The job of these cells is to secrete a factor that keeps hair cells healthy within the ear. If the stria vascularis cells are not pigmented, they are defective and lead to hair cell death within a puppy’s first few weeks, resulting in deafness. Unfortunately, this takes place in the inner ear and is, therefore, not visible to the eye; often, it is not obvious that a puppy is deaf. Deaf puppies may play harder than their littermates (because they cannot hear the yelps they inflict); also they may be hard to wake, or be seen to be following cues from the other puppies. Hunches must be confirmed with BAER testing.
Those who train working dogs also utilize BAER testing. These dogs need to be able to hear in both ears in order to localize the source of a sound. A dog can be unilaterally deaf (deaf in one ear), so that he can still hear but cannot tell where the sound is coming from. Others whose dogs experience chronic ear infections may seek BAER testing to find out how much hearing loss their dog might have experienced as a result of infection. BAER testing is also used to aid in the diagnosis of more serious medical conditions, such as vestibular (inner ear) disease or brain tumors.
BAER testing can be done only at one of the centers that specialize in the test. (Click here  for a list of BAER testing sites.) However, BAER testing is occasionally available at “health clinics” at major dog shows.
Don Preisler, UC Davis School of Veterinary Medicine