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White Cats & Deafness

White Cats & Deafness

Maine Coon InfoWhite Cats & Deafness

The White Cat
White is probably the most difficult to explain and understand; Why? Because White is NOT a color. The gene that results in a white cat is one that allows a “cover” or “mask” of white to hide the true color of the cat. Many white cats are born with a spot of color on their heads, and that color will indicate the true color of the cat. Therefore, a cat that appears to be white will breed the same as any of the other colors, depending upon which color it “masks”.
White Cats & Deafness
We often joke about cats not listening and ignoring us (not Maine Coons of course!). Well, when it comes to white cats there may be some truth in that statement. White cats are more likely than colored cats to have congenital deafness (present from birth). Cats that are white and have blue eyes are particularly susceptible.
Deafness may occur in one ear or both ears and is caused by an absence or abnormality of melanocytes. Melanocytes are melanin-producing cells like those in the skin that has to do with color. Interestingly, they are also found in the eye and the ear. Which is why we often see white, blue-eyed cats that are deaf. Maine Coons, Persians, and Ragdolls are felt to have a higher incidence of congenital deafness.
How Common Are White Maine Coon Cats
White cats make up 5% of the total cat population. Of that population, about 2% have two blue eyes and those cats have a 40–60% chance of being deaf. White cats with non-blue eyes have a 10–20% chance of being deaf.
What is the BAER Test
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 cochlear nerve and later peaks are produced within the brain. The response from an ear that is deaf is an essentially flat line.
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 the shoulders. It is rare for a cat to show any evidence of pain from the placement of the electrodes – if anything the cat 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 cat becomes extremely agitated, which can usually be avoided with gentle handling. A printout of the test results, showing the actual recorded waveform, is provided at the end of the procedure.
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