Disorder - Deafness

Organ Systems Involved
Nervous/sensory

Alternative disorders described within LIDA

None known

Alternative Names
Hearing impairment

Presenting Signs

In this type of hereditary deafness in white cats, the cochlea (inner ear) degenerates at around three to four weeks of age, causing deafness. Scientists believe that the gene for white colour in cats suppresses the melanocytes (pigment-producing cells, associated with the cochlea), and this causes degeneration of the cochlea. The nerves that travel from the cochlea to the brain degenerate and are underdeveloped as a secondary consequence. Deafness can be profound/complete, but some white cats with a family history of deafness are only partially deaf.

The primary sign of deafness is failure to respond to sounds, e.g. a sleeping cat fails to awaken with noise, or react to the source of a sound. Other signs of deafness include behaviour such as an unusual voice, hyperactivity and lack of a reflex of alertness. Deaf kittens learn to rely on their littermates for visual cues, so often cry loudly when separated, as they become highly dependent upon their physical presence. They are usually more aggressive with littermates because they do not hear them calling in pain, which would normally terminate rough play. Outdoor cats may be more at risk of road trauma.

Cats at Risk

Highest prevalence is seen in white cats, especially those with blue eyes. The prevalence of deafness increases as the number of blue eyes increases from zero to two. However, not all blue-eyed white cats are deaf.

PubMed References
Deafness

Contributor
Kylie Aplin