A cat can become deaf after an injury or illness in the ears. Deafness can also be congenital.
The function of the ear is to translate sound into nerve signals that are perceived by the brain.
When sound waves hit the eardrum, an oscillation occurs which in turn is transmitted to the small bones inside the ear and from there to nerve receptors that send a signal via nerves to the brain’s hearing center.
In deafness, there is a defect somewhere in this mechanism, ie in the eardrum, the ear bones, the nerves to the brain or the hearing center in the brain.
Acquired deafness – deafness due to illness or injury – can be caused by, for example, ear infections or trauma. Recurrent or chronic ear infections mean an increased risk that the middle and inner ear will also become inflamed, with damage to the hearing organ as a result. In case of damage to the eardrum, such as a severe ear infection, certain types of ear drops can cause damage to the inner parts of the ear.
Congenital deafness can occur in all cats, but it is more common in individuals with white fur and blue eyes. Cats with congenital deafness should not be bred.
Symptoms
It can be difficult to detect signs of hearing loss in cats. If the cat lacks hearing in both ears, it may have a deviant behavior compared to hearing and be more easily frightened and insecure.
Diagnosis
It is difficult to test the hearing of cats in the same way as in humans. Possibly you can try to make unexpected noises out of sight of the cat and see if it reacts. This presupposes that the cat does not react to visual or sensory impressions (eg traction or vibration) in connection with the sound. Nowadays, there are methods for measuring hearing using electrodes on the cat’s head, so-called BAER test. Equipment and expertise for such examination are available at some animal hospitals.
Treatment
Deafness can not be treated.
However, any underlying disease such as ear inflammation should be treated so that the cat does not get discomfort or pain from it.
Forecast
How well cats handle deafness varies from individual to individual. Some cats become very insecure and perhaps aggressive, and in these cases killing should be considered. Others do well despite hearing loss, but you should think before you leave a deaf cat out yourself because a deaf cat can more easily have traffic accidents etc.