Feb
21
2007

Since opening a Companion Animal Bioacoustics Lab last year, Peter Sheifele, PhD, has had pet owners lining up to see if their dogs are deaf. They’ve traveled from Missouri, Florida, and California to Connecticut to gauge their pets’ acoustic hearing spectrums. Although treatment options are limited for deaf dogs, tests can rule out brain tumors, behavioral issues, and they can give pet owners tips to keep deaf dogs safe from harm.

Although shaky, statistics indicate that one in five dogs are born deaf and many others develop hearing problems as they age, which may explain the high consumer demand for Sheifele’s services.

“It’s heartwarming,” Sheifele says of the weekly requests he gets from pet owners. “It gives us some hope that we’re doing some good here.”

The test – recently featured in Dog Fancy Magazine – is not new to veterinary medicine but its popularity with clients illustrates a lack of awareness about the tests, said George Strain, PhD, who has tested about 10,000 dogs during his career. Strain, a professor of neuroscience at Louisiana State University School of Veterinary Medicine, has authored several research papers on deafness in dogs and cats

“Veterinarians who graduated 20 years ago may not know about these tests,” he said. Strain teaches veterinary students at Louisiana State University and gets an increasing number of veterinary referrals for the tests that he provides for $51. Other groups charge anywhere from $200 to $300 for the same test, Strain said.

Strain uses a Brainstem Auditory Evoked Response test on dogs and cats, and said that ethical breeders regularly test puppies since bilateral deafness is difficult to discern when dogs are in the litter. Deaf dogs tend to rely on their other senses and will follow their littermates who can respond to commands.

The two tests offered at Sheifele’s lab - otoacoustic emissions (OAE) and ABR –identify whether deafness is congenital or noise induced and if the problem stems from the inner ear or auditory portion of the brain. The tests are free at this time.

Scheifele admits that animal otology is “not an official vocation,” but hopes it will become one, and has developed a program to teach animal hearing and audiology at the University of Connecticut.

“Right now veterinarians don’t typically get audiology as part of their training,” Sheifele said. “Neither do MDs, which is why there is a referral relationship in the human world.” That is exactly the type of relationship he hopes to establish with veterinarians.

Strain acknowledges that there is not an official animal otology vocation but points to an increasing number of veterinarians who specialize in neurology and offer hearing analyses. Referrals, however, may be the way to go with hearing tests for the foreseeable future since equipment costs about $20,000, a hefty investment for private practitioners.

Industry Benchmarks
For the last 10 years Sheifele has focused his research on cats, dogs, ferrets, and horses – with the goal of establishing a norm for dog breeds and genders that suffer from hearing loss.

A neuroaudiologist who studied marine mammals in the Navy, Scheifele has tested 27 animal patients including two cats, 20 dogs, and a whale since opening his university funded lab in 2005. He tweaked human medical equipment to be used on the pets, and minimal adjustments were needed since mammalian ears do not differ much with the noted exception of whales, Scheifele said.

One interesting difference he has noted is that dogs do not have a wave four in the seven-wave spectrum identified by human audiologists. “It’s mysterious,” Sheifele says, “But we’re not concerned.”

As most veterinary professionals – and pet owners – know, dogs can hear noises at much lower frequencies because of a high volume of hair cells. For example, Sheifele says that dogs can hear sounds that register 50 to 23,000 hertz while the human range starts at 20,000 hertz.

Although professionals disagree on the efficacy of hearing aids in pets, Veterinary Pet Insurance covers the cost of hearing aids that are placed in the inner ear. After testing thousands of dogs, Strain does not usually recommend hearing aids because – as he says – “Deaf animals don’t suffer from their deafness. It’s not like hip dysplasia. They’re not in pain.” Tests, however, can help pet owners understand precautions that they should take with deaf dogs and positive results rule out behavior issues, like being stubborn.

The biggest liability for a dog that is deaf in both ears is that they can sometimes bite reflexively when they are startled, he said.

Strain believes that with increased awareness among breeders, genetic deafness in dogs is decreasing and as more veterinarians refer or test dogs the incidence will continue to decline.

Comments (1) -

Saagar
SaagarAustralia
10/30/2013 6:04:24 PM #

While i am not familar with canine audiology, yet, i am studying audiology and i couldnt help but notice this article says "the human hearing range starts at 20 000hz". Im not sure what the author is on about however i will try and clear this up.
Human hearing in a perfect case, in a 12 year old child(after peripheral and neural audiological structures have developed) would have a hearing spectrum of 20hz - 20 000hz in a perfect world. (As audiologists we test octave frequencies beginning at 500 hz to assess this spectrum..
However as we age, we loose hearing acuity in regards to the active mechanism or cochlea amplifier, that mediates the function of the cochlea and its ability to amplify quiet sounds. Most significantly this phenomenon is shown in the high frequencies(frequencies above 2000 hz). If the article is to be believed then the dog ear can decode sound pressure waves up to 23000 times /second (20 000 hz) . From what i understand, the "invisible sound" training tool produces a supersonic (greater than 18-20 000hz) sound that only dogs can hear due to better High frequency hearing which would be consistant with this article, however after running the signal through an amplifier i was able to hear the tone created by the tool.  So this may not be the phenomenon relating to the dogs hearing acuity.
Spectral studies show ( psychophysical tuning curves) that dogs have similar spectral resolution as humans (they can hear the same range of frequencies) however they also show that dogs are able to detect the same sounds we hear at lower levels of sound "intensity".So instead of saying that dogs have better low frequency hearing, the author possibly ment dogs have better "low intensity" hearing. IE at sub-aural thresholds.

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