Adult Onset Deafness in Border Collies

[Margaret M Wheeler]

I?m interested in deafness, in part because I trained as a teacher of the deaf and in part because of the occurrence of deafness in Jack Russell terriers, a breed that I have had some experience with. Because deafness is such an important issue with regard to stockdog work, I wanted to share my thoughts and raise a couple of questions that seem important to me. Also, at the end of my post I have linked to Dr. George Strain's website, a site that seems to be an excellent resource on deafness in dogs.

 

Scamper, my 12 year old Jack Russell terrier, BAER tested normal at around two years of age, but she has become almost completely deaf in the last couple of years. It?s important to note that she might not be deaf due to a sensorineural hearing loss. A BAER test could help me know the cause of her hearing loss because the test bypasses the structures of the ear canal and the middle ear and tests the ability of the inner ear to detect(for lack of a better word) sound. So, if I BAER tested Scamper tomorrow, and she BAER tested normal, I would have good reason to believe that her deafness was a result of some problem that did not involve the inner ear. It might be that, for one reason or another she has a fairly common form of mechanical hearing loss i.e. the tiny bones in her middle ear are no longer vibrating as they should in response to sound and so are not transmitting those vibrations to the inner ear via the eardrum.

 

I think it is safe to say that most deafness found in newborn puppies is a direct consequence of an inherited defect for sensorineural hearing loss. On the other hand, it is much more difficult to be certain of the causes of age-related deafness (presbycusis), even deafness that is known to sensorineural. Disease, trauma, dangerous noise levels, toxic substances can all contribute to sensorineural hearing loss in an adult dog.

 

Certainly, the structures of the inner ear often become less and less functional with age (at least in dogs and humans), and it has been established that general physical aging has a genetic component.

 

Still I believe that some degree of sensorineural hearing loss in older dogs should not be considered to be pathological.

 

So for me some of the important and interesting questions with regard to hearing loss and the selection of breeding animals for stockdog work are:

• With what frequency do we see adult onset deafness in border collies?
  
• At what age do we consider adult hearing loss to be a defect in the dog?
  
• What degree of hearing loss would we deem ?pathological? in adult dogs?
  

Below, I have pasted a paragraph from an article that Dr. George Strain. This article is just one of many useful resources offered on Dr. Strain's website.

http://www.lsu.edu/deafness/deaf.htm

 

...sensorineural deafness can be primary or secondary. Primary deafness results from destruction of hair cells in the cochlea without antecedent events. This occurs in hereditary deafness in Doberman pinchers, some forms of ototoxicity, and presbycusis. Secondary deafness occurs when hair cells die as a consequence of other damage in the cochlea, most commonly to the stria vascularis. This occurs in pigment-associated hereditary deafness and some forms of ototoxicity. Degeneration of the stria vascularis eliminates the high K+ levels in the fluids surrounding the hair cells, resulting in death of the hair cells and deafness. In pigment-associated hereditary deafness, the strial degeneration and hair cell death usually occur 2-4 weeks after birth.

 

George M. Strain, Hereditary Deafness in Dogs and Cats:

Causes, Prevalence, and Current Research. Tufts' Canine & Feline Breeding and Genetics Conference, October 2-4, 2003,Sturbridge, MA

[Caroline]

Hi Margaret,

I have a friend with a BC that had adult onset deafness, around age 7 or so. He had already done obedience competition and had a UDX so the hand signals were already trained. He was from a litter in British Columbia where that line has shown deafness in others similiarly bred.

Caroline

[Margaret M Wheeler]

Hi Caroline,

 

Thanks for replying. Is your friend aware of the post on Sheepdog-L regarding this issue?

[Caroline]

I doubt it, he doesn't surf the net. Can you send me a link to the discussion or do you have to be a member to read it?

Caroline

[Margaret M Wheeler]

Sheepdog-L has an open membership, meaning you don't need approval from the moderator to join, but I don't know if you can read there without a membership. I'll send you an email with the post in it.

 

http://groups.yahoo.com/group/Sheepdog-L/

[tucknjill]

I think my grace has the beg. of adult onset deafness. I have had her BAER tested and she does hear, however they cannot determine level of hearing with this test. I have heard of other tests that can determine level of hearing, but I was told that they were very costly and not horribly informative..any thoughts on that as I know virtually nothing about all this. A wonderful new problem for me to learn all about.sigh.

[laurie etc]

Sam - where was she BAER tested? I have used Dr. Gainsberg in Baltimore, MD. I was under the impression that the test could differentiate between total deafness and partial or minimal hearing, depending on the frequencies they use. I know of a 10 year old dog who was tested, pronounced "hearing" but had some old age lower frequency hearing loss. The neorologist said this was a normal finding in an older dog.

Conversely, this summer i took some 7 week old pups to him, (and one young adult. The adult went first and was pronounced deaf in one ear... until the neorologist started on the first pup, realized that there was "dry crud" on the probe for the left ear, retested the adult and said that the "crud" down in the adult's left ear had caused a false reading and that after cleaning the probe and re-testing she was perfectly fine (except she needed a deep ear flushing under sedation). :eek:

[tucknjill]

Susie Hughes in NC did it..I know her back from my Dalmatian days... She did try some of the lower frequency testing, but she says there is no firm data to acurately interpret the readings as to HOW MUCH she can actually hear...or something along those lines. I need to talk to Dave Fetterman about all this as I know he has had some advanced testing done on Leah as well as Sandy Hornung and Rocky.

[Joan]

Originally posted by tucknjill:

Susie Hughes in NC did it..I know her back from my Dalmatian days... She did try some of the lower frequency testing, but she says there is no firm data to acurately interpret the readings as to HOW MUCH she can actually hear...or something along those lines.

When Susie tested Jake, 6-7 years ago, she said he had about 2 percent of his hearing left. Maybe that was just her way of saying my dog was totally deaf. Jake was 8 at the time, and he had never had any ear problems or any known reason for deafness.

[laurie etc]

wow - 2% isn't much - is it? I do wonder how she could quantify that? Dr Gainsberg lightly sedates all the dogs he does because he said that sometimes movement can cause the probes to pick up a response that looks like hearing on the printout when in fact the dog cannot hear.

 

My daughter's BC is a uni- diagnosed at around a year old - but he is so responsive and compensates so well, we didn't even suspect it until he was BAER tested.

 

I think the late-onset deafness study is very interesting. It is a little scary if there is a genetic component to deafness that doesn't kick in until the dog is an adult and working....I wonder if it's not so much genetic, but something that the pups in utero (or their dam) might be exposed to.

When I had Goldens I know that 2 of them became pretty hard of hearing late in life - they were 14 and 13 years old when they died. They had gone through so many ear infections at that point, after reading the LSU articles I'm pretty sure that is what caused it .

[tucknjill]

I dont know about a genetic component, but I will say Grace's mother is all white with a black head...but then there is Tucker, her full brother and he is fine at 9. And I really have no backup other than things I see in her work to lead me to the hearing loss conclusion. I guess I will just wait and see how she runs this year before I take it to the next step.

[Margaret M Wheeler]

Hey gals,

 

Welcome home Sam!

 

Thanks for replying.

 

Just got home from my lesson with Carol and now on the run to kids' soccer practices. I have a couple of questions that will have to wait til tonight or they won't make any sense. Course there's no guarantee that I'll make sense later but I'll have more time to try.

[tucknjill]

Well I will be gone in the am, so if I dont write back, I will catch you Monday! Gotta go clean the kennel and pack then the fair thurday and a packed day friday...sooooooo you get the idea..talk soon