test known as the brainstem auditory evoked response (BAER) or brainstem
auditory evoked potential (BAEP) detects electrical activity in the
cochlea and auditory pathways in the brain in much the same way that
an antenna detects radio or TV signals or an EKG detects electrical
activity of the heart. The response waveform consists of a series of
peaks numbered with Roman numerals: peak I is produced by the cochlea
and later peaks are produced within the brain. The response from an
ear that is deaf is an essentially flat line. In the sample recordings
shown below, Puppy 1 heard in both ears, Puppy 2 was deaf in the left
ear, Puppy 3 was deaf in the right ear, and Puppy 4 was deaf in both
ears. Because the response amplitude is so small it is necessary to
average the responses to multiple stimuli (clicks) to unmask them from
the other unrelated electrical activity that is also present on the
scalp (EEG, muscle activity, etc).
response is collected with a special computer through extremely small
electrodes placed under the skin of the scalp: one in front of each
ear, one at the top of the head, and one between and behind the eyes.
It is rare for a dog to show any evidence of pain from the placement
of the electrodes - if anything the dog objects to the gentle restraint
and the irritation of wires hanging in front of its face. The stimulus
click produced by the computer is directed into the ear with a foam
insert earphone. Each ear is tested individually, and the test usually
is complete in 10-15 minutes. Sedation or anesthesia are usually not
necessary unless the dog becomes extremely agitated, which can usually
be avoided with patient and gentle handling. A printout of the test
results, showing the actual recorded waveform, is provided at the end
of the procedure. Test results are confidential, but anonymous details
will be used in Dr. Strain's ongoing deafness research for later publication
and education of veterinary practitioners.
- deaf in both ears (i.e., totally deaf)
- deaf in one ear (often called "unis")
Jack Russell Terrier breeders should BAER and CERF test BEFORE breeding.
Terriers that are affected with genetic diseases should not be bred.
Know your pedigrees and the health of the ancestors prior to breeding.
Deaf dogs need very special handling and should be spayed or
neutered as soon as possible.
that do BAER testing in California
25 Adeline Dr.
Walnut Creek, CA 94596
925-930-0383, 925-934-6596, fax 920-930-7941
Southern California Surgical Group
17672 Cowan Ave., Suite A-100
Irvine, CA 92614
949-833-9020, fax 949-833-7530
Redwood Veterinary Clinic
1946 Santa Rosa Ave
Santa Rosa, CA
707-542-4012, fax 707-542-2440
2965 Tuxedo Place
Santa Rosa, CA 95405
Veterinary Specialty Hospital
P.O. Box 9727
Rancho Santa Fe, CA 92067
619-759-2543, fax 619-756-2543
Old River Veterinary Hospital
520 West 11th St.
Tracy, CA 95376
Animal Dermatology Clinic
5701 H Street
Sacramento, CA 95819
916-451-6445, fax 916-451-2257
UC Davis Vet School
Davis, CA 95616
Plaza Veterinary Clinic
7340 Firestone Blvd., #117
Downey, CA 90241
is complete as of the date published. JRTNNC has not verified the current
standing of these veterinarians or their practices. If you would like
to have a professional referral please call If you know of a veterinarian
who does testing in California, please send their name, phone and email
to us at JRT
information on Deafness and BAER testing:
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