Unilateral Deafness in Dogs (and Skip?)

2 weeks ago 10

Ever since I got Skip, three and a half years ago, he has turned preferentially toward me to his left, even if to the right is shorter. If I call him when I am at six o’clock, and he is facing three, he turns to his left and runs 3/4 of the way around the clock face to me. Here’s an example:

Note that when asked to go counter clockwise, he did go to the right, because he knows Come Bye means to run around the sheep with them on his left. But if you call him to come, he almost always turns to his left.

Why would a dog do this? Obviously, the expected behavior would be to turn toward the sound the shortest way, in the example above, turning 1/4 of the way rather than 3/4’s. Not doing so is a one of the signs of unilateral deafness in a dog, one I discovered early in my career while working with a client’s dog whose behavior was a mystery. Sometimes he was beautifully compliant, sometimes, uh, not. His owner was frustrated, and, human that they were, attributed his lack of compliance to willful dis-obedience. I barely noticed that he tended to always turn in one direction, until one day they were out at the farm when he called the dog to him when the dog was facing directly away. “Butch,” we’ll call him, turned toward us but then scanned to our right and left, before zeroing in on us once one of us had moved.

Ah ha! He couldn’t localize us until his eyes saw movement. Sure enough, it turned out that Butch was unilaterally deaf, or deaf in one ear. Mammalian brains need two ears to localize sound, and unilaterally deaf dogs can hear, but can’t locate where the sound is coming from. This condition occurs in people as well as dogs, and makes not only localizing sound difficult, but also makes it harder to discriminate speech in noisy environments. There is rarely a treatment, but knowing about it can make working with a unilaterally deaf dog easier for everyone, especially the dog. Skip doesn’t tend to have to scan to find me that often, but he has seemed confused in situations where he couldn’t see me or in noisy environments. Could this explain his behavior?

 Certainly, some breeds of dogs suffer from unilateral deafness more than others, including, infamously, Dalmations, Border Collies, Aussies, etc–mostly dogs with genes that carry a merle factor. (Every responsible BC breeder knows not to breed a dog with a lot of white on it, especially on their heads.) The classic behavioral signs are what my client’s dog, Butch, illustrated–scanning visually for information his ears couldn’t discern, and what Skip does–turning preferentially toward what is presumed to be the working ear.

I have wondered about Skip and his hearing since the day I got him. Besides the wonky turning toward me when called, Skip has drifted to the left of the sheep, also since the day I got him, no matter how hard I have worked on it. If he needs to drive them in a straight line by staying on the sheep’s right shoulder, he drifts to the left and pushes them in the wrong direction. When I first sent him on outruns, he didn’t stop at the “top,” say at twelve o’clock, but ran to three o’clock and drove the sheep to nine o’clock.

He is also Mr. Inconsistent. Sometimes, on the same day, on the same course, he looks like a different dog from one run to another. Most recently he was on a new course with a lot of extraneous noise (traffic from a highway), and his first run was a disaster, his second just fine. That also is typical of unilaterally deaf dogs. Once the dog is familiar with the course he knows where his handler is without having to localize them.

Of course, there are other reasons for this behavior. His eyes? Something structural? Conditioning? But, one of my first BCs was deaf in one ear, so that’s always been high on my list. However, the only reliable test of hearing is the BAER test, which requires special equipment, may require the dog to be anesthetized, isn’t cheap, and results in a diagnosis for a condition that has no treatment. Because of Skip’s heart condition and the factors above, I haven’t had him tested.

But after thinking about it off and on for years, I decided to turn this question into a win/win. What if I got Skip tested–IF I could do it safely given his heart–and used the experience to spread the word about unilateral deafness, which is possibly more prevalent than people realize. (About 2% in one study done on BCs in the UK, for example.) Not knowing where a sound comes from doesn’t sound like a big issue, but if you are worried about the world in any way, not being able to localize sound could be frightening. It’s believed that some dogs who are deaf in one ear exhibit defensive aggression, but I haven’t seen any studies. So I booked an appointment at the University of Wisconsin School of Veterinary Medicine, one of the few places in the area where you can get a BAER test test done.

I still woke up at 2:30 AM the morning of the test, anxious about the whole thing. I girded myself to cancel everything at the last minute if I wasn’t assured that any risk to Skip was so minimal as to be too small to measure.

Here’s Skip and me waiting for the doctor’s entrance. Would we go ahead with it, or cancel? I had no idea at that point. I was told to fast him when they made the appointment, because they usually used some kind of “anesthesia.” (Really it’s a sedation, very different than general anesthesia, but that’s the word I remember being told, although I can’t guarantee you what was actually said.)

Within just a few minutes, we met neurologists Dr. Starr Cameron (on the left) and Dr. Karina Pinal (on the right), who assured me that, given Skip’s compliance (I WAS SO PROUD OF HIM ❤️), we could try the test without any kind of sedation. Yayayayayayayay! Skip’s expression says it all.

After an hour long standard neurological test, (no photos, sorry, busy helping keep Skip comfortable while he was poked and prodded), it was time for the BAER test.

The BAER test, which stands for Brainstem Auditory Evoked Responses, involves putting ear plugs into the dog’s ear, and inserting five needles under the skin, which “reflect neuronal activity in the auditory nerve, cochlear nucleus, superior olive and inferior colliculus of the brainstem.” Say that fast three times.

Here’s Skip getting an ear plug placed by kind and gentle Veterinary Technician Stephanie Paulson. Stephanie said the dogs are bothered more by the ear plugs than the needles. Surprising, but exactly true with Skip, who shook out the first ear plug but then stayed still like a trooper when it was re-inserted, the needles put in, and the techie part of the test was done.

The results came fast and clear: Skip can hear in both ears. The test can’t compare hearing acuity, it’s an either/or test, but my hypothesis of unilateral deafness was not supported.

Interesting. I certainly didn’t want Skip to be deaf in one ear, but . . .  I really thought it would be great to have the mystery of his behavior solved.

And, then, it was.

Drs. Cameron and Pinal explained to me that based on their neurological exam, Skip’s adorable head tilt (and possibly floppy ear? less likely, but possible) on his left side was consistent with “chronic, compensated vestibular disease,” most probably congenital. Here’s a photo I took just days after we got him:

Granted, dogs tilt their heads all the time, the better to localize sound, but Skip’s is more constant, and especially noticeable to me when he runs. The neurologists picked it up instantly, even at a walk. I’ve always said he runs a bit “sideways,” wondering more about his frame than his head. I can’t go into the weeds today on the function of the vestibular system beyond what we all know–that it controls balance for example, but will add this from Wikipedia, that explains his turning to the left over the right: The [ear] canals are arranged in such a way that each canal on the left side has an almost parallel counterpart on the right side. Each of these three pairs works in a push-pull fashion: when one canal is stimulated, its corresponding partner on the other side is inhibited, and vice versa.

That is what the neurologists said best explains his preference for turning left over right. It’s almost like a force field pushing him that way from the right side, in which the working nerve (from his inner ear) on the right “overstimulates” that side of his head. (I’m taking liberties here, simplifying for the sake of our own brains.) Wow. I love discovery.

But, ah, what of his relentless desire to stay on the left side of the sheep, such that they are on his right? That seems contradictory at first, but . . . wild speculation here: Could it be that when he needs information about where he is in space, relative to a moving object like sheep, he is more comfortable keeping them on the side that has no deficit? That gives him more information? Just a hypothesis, but I have to say I have worked three and a half years to “fix” this, and have only been able to manage it. One clinician, far wiser and experienced than I, said, “Yeah, I’ve seen a dog like that, not much you can do but manage it. They seem to be born with it.” But others have given me lots of good advice that I’ve tried and tried, no avail. And, if the one clinician was right, what was it that caused the behavior? I’ve wondered about his ears, his eyes, and his structure, but never his vestibular system. Fascinating. Honestly, it feels like a relief. I’ve always felt that somehow I should be able to do more than “manage” it, that if I was a better sheepdog trainer I would figure it out.

The day ended as well as it possibly could have. Skip came through without much stress at all, the staff at the UW Vet School could not have been kinder, more receptive to handling Skip gently, or more informative. Here are the major players, Dr. Pinal, Stephanie Paulson, Dr. Cameron, and of course the star, Skip. THE BEST DOG EVER ❤️. (Sorry, can’t help it. I was soooo proud of him.)

Except for some small amount of stress while getting set up for the test (both me and Skip), the whole experience was actually fun. Here’s the whole group, including technician Karen Garcia-Olmo  and 4th year vet student Macy Peterson. They were so fun I invited them out to the farm. Seriously.

One last thing I should say, full disclosure. I have no idea what anyone else’s experience would be at UW Vet. The fact is, I know people. Dr. Calico Schmidt is a dear friend who helped smooth the way for me to be in the room with Skip at all times. They all knew who “Dr. McConnell” was. I could afford the $510 fee. But I will say that everyone at the clinic could not have been nicer and it’s hard to imagine them doing personality transplants for different clients. I will add, truth in lending, that that parking is a nightmare and the waiting room lobby is too TOO small and when are they ever going to fix that?

If you’re still with me on this ramble, jump in if you’ve ever had a dog who was unilaterally deaf. Do you notice if your dog doesn’t seem to locate sound, or always turn in one direction? Ever had a dog like Skip with a vestibular deficit? Think my hypothesis about why Skip drifts left makes sense? Other ideas? (Sheepdog folks jump in!)

MEANWHILE, on the farm: Here’s Skip and the sheep this morning; I wanted to get in a quick work session before his and Maggie’s monthly chiropractic this afternoon.

Last night I came in from the barn and said to Jim: “Our sheep are not fat. They are obese.” Good grief, girls, your hay ration is going down for a few months.

Beyonce, one of our oldest ewes, is still going strong. Fat, but strong.

Skip and I came down after we were done to put the four-wheeler into the barn in case it rains tonight. I turned to close the gate and saw this scene of Skip resting after his work out. Muted, but something about it caught my eye . . .

May something wonderful catch your eye this week too. I wish you all a thankful Thanksgiving, I hope your life is such that you can do that, no matter how small the joys. Join in if you have ever wondered, or found out, that your dog is deaf in one ear. We’re all ears. Ahem. You see what I did there?

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