10. Giving a hearing test to a cat is sometimes tricky, but it can be done. Behavioral tests where veterinarians make a noise and look for responses have several problems, Strain says. They can’t detect unilateral deafness, for example, and it’s not uncommon for cats to be stressed out and unresponsive during the tests.
“The most objective test we have available to us is the BAER test, which stands for brainstem auditory evoked response,” Strain says. In these tests, he explains, electrodes are placed under the skin on the top of a cat’s head and in front of each ear. A sound is then played into each ear, and the electrodes detect electrical activity in the auditory pathway.
“It’s like a TV antennae picking up a signal deep in the brain,” he says. A series of peaks in activity indicates the ear heard the noise, while a lack of activity peaks suggests the ear is deaf.