HEARING/BAER TESTING
We now offer Brainstem Auditory Evoked Response (BAER) testing to screen for hearing abnormalities.
In veterinary medicine, the BAER is most often used to screen dogs for congenital deafness. Numerous breeds are at risk for this disorder and in the vast majority it is related to coat color, or lack thereof. Please call our clinic to schedule a time to screen your dogs for congenital deafness.
How does it work?
The test works by generating audible “clicks” that are used to stimulate the acoustic nerve (vestibulocochlear nerve/cranial nerve VIII) which is then read by our machine to produce a repeatable waveform in dogs with normal hearing.
This is most often done for breeders interested in screening their dogs for congenital deafness.
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The BAER can also be used to examine hearing in patients suspected of having conductive deafness. Debris in the ear canal, thickening or perforation of the tympanic membrane, sclerosis of an ossicle or fluid in the middle ear can result in this condition. On BAER this is demonstrated by decreased amplitudes and prolonged latencies (if severe, they may be flat).
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Presbycusis is an age-related deafness that is seen in older dogs. Primarily considered a sensorineural deafness, in some dogs it may also have a conductive component so BAER results can vary.
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Duplicate recordings for each ear should always be performed to insure that the results are reproducible.
What breeds of dogs are at risk?
Two pigmentation genes in particular are often associated with deafness in dogs: the merle gene (seen in the Collie, Shetland Sheepdog, Dappled Dachshund, Harlequin Great Dane, American Foxhound, Old English Sheepdog, and Norwegian Dunker hound among others) and the piebald gene (Bull Terrier, Samoyed, Greyhound, Great Pyrenees, Sealyham Terrier, Beagle, Bulldog, Dalmatian, English Setter).
The OFA (Orthopedic Foundation for Animals) has compiled some data to show the prevalence of the more common breeds associated with congenital deafness:
