BAER Testing Explained
Brainstem auditory evoked response (BAER) testing is an electrodiagnostic test used to evaluate the hearing of dogs, cats, and other domestic animals.
It evaluates the components of the external ear canal, middle/inner ear cavities, cranial nerve, and selected areas of the brainstem. It is a non-invasive procedure that takes 5 to 15 minutes to perform. If the hearing threshold needs to be determined, sedation is recommended-more often in older patients. Puppies, however, are fully awake and do not have any issue with being tested.
From small subcutaneous electrodes and externally applied acoustic stimuli of different intensity, we record numerous waves, each of which represents composite neuronal activity.
What Are the Uses of BAER Testing?
1. Early diagnosis of hearing loss secondary to cochlear agenesis/degeneration.
2. Assessment of brainstem (caudal part of the brain) function.
3. Conductive hearing loss results from the external ear canal and middle ear space dysfunction.
4. Sensorineural hearing loss results from the cochlea, cochlear nerve, or central auditory pathway dysfunction.
Hearing Loss in Puppies
Most responsible breeders of dogs at high risk for congenital deafness will test litters of puppies before selling them. Such breeds include Dalmatians, Bull Terriers, English Setters, English cocker spaniels, Australian Cattle Dogs, Border Collies, Australian Shepherds, and Jack Russell Terriers, to name a few.
Any breed that carries the piebald or merle gene is predisposed to deafness.
Puppies are tested at seven weeks of age. Because dogs can lose hearing up to 16 weeks of age, retesting is often done, especially before breeding, if there is a questionable reading on the first test; or if the owner notices any problems.
If a puppy tests negative in one or both ears, usually nothing can be done to regain hearing if they suffer from cochlear degeneration. The ears are checked for any infection interfering with the test, but congenital deafness cannot be restored. Chronic ear problems can cause thickening of the ear canals and cause poor signals to the brainstem, which would cause poor hearing and a questionable test. In this situation, the patients will often be retested after being treated appropriately.
A dog that seems to be able to hear but cannot locate where the sound is coming from may be affected by unilateral hearing loss (hearing in one ear only). A BAER test can confirm this and identify the affected ear.
Contact Details
Narelle Hammond (Baercom Technician)Sydney, NSW, Australia
Phone : +61419787375
Email : [email protected]