The hearing 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).

The 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.

Bilateral - deaf in both ears (i.e., totally deaf)
Unilateral - deaf in one ear (often called "unis")

All ethical 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.

Vets that do BAER testing in California

Dr. Michael Ericson
25 Adeline Dr.
Walnut Creek, CA 94596
925-930-0383, 925-934-6596, fax 920-930-7941
HappyK9@earthlink.net

Dr. Stephen Hanson
Southern California Surgical Group
17672 Cowan Ave., Suite A-100
Irvine, CA 92614
949-833-9020, fax 949-833-7530

Dr. Richard Hoskins
Redwood Veterinary Clinic
1946 Santa Rosa Ave
Santa Rosa, CA
707-542-4012, fax 707-542-2440

Ms. Susan Hurt
2965 Tuxedo Place
Santa Rosa, CA 95405
707-571-1890

Dr. Greg Kortz
Veterinary Specialty Hospital
P.O. Box 9727
Rancho Santa Fe, CA 92067
619-759-2543, fax 619-756-2543
KCJAZ@aol.com

Dr. Thomas Schubert
Old River Veterinary Hospital
520 West 11th St.
Tracy, CA 95376
209-835-5166

Dr. Candace A. Sousa
Animal Dermatology Clinic
5701 H Street
Sacramento, CA 95819
916-451-6445, fax 916-451-2257

Ms. D. Colette Williams
UC Davis Vet School
Davis, CA 95616
530-752-1393

Dr. Mark H. Wright
Plaza Veterinary Clinic
7340 Firestone Blvd., #117
Downey, CA 90241
562-928-2234

This listing 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 Email.

For more information on Deafness and BAER testing:

Check out our Canine Genetics Book Selections

http://its2.ocs.lsu.edu/guests/senate/public_html/deaf.htm