Deafness

Congenital sensorineural deafness is associated with white coat color and blue eyes in dogs and cats. It results from degeneration of the stria vascularis in the cochlea during the first few weeks of life. The condition is linked to the piebald (S) and merle (M) genes in dogs and the white (W) gene in cats. It can be unilateral or bilateral.

Symptoms & Signs

• Failure to respond to sounds or name
• Excessive barking
• Difficulty training
• Startling when touched unexpectedly
• Not waking to loud noises
• Unilateral: head tilting toward hearing ear

Causes & Risk Factors

Genetic: associated with lack of melanocytes in the stria vascularis of the cochlea. The absence of melanocytes leads to degeneration of the organ of Corti. Linked to coat color genes: merle, piebald, extreme white. Breeds: Dalmatian (30% affected), white Bull Terrier, white cats.

Diagnosis

Brainstem Auditory Evoked Response (BAER) testing is the gold standard, detecting both unilateral and bilateral deafness. Can be performed from 5 weeks of age. No other test reliably detects unilateral deafness.

Treatment

No treatment can restore hearing in congenital sensorineural deafness. Management involves hand signal training, vibration collars for recall, safe fenced environments, and avoiding startling the animal. Cochlear implants are experimental.

Prevention

BAER testing all breeding stock in affected breeds. Avoiding breeding two merle dogs together (double merle). Selecting against extreme white in breeding programs. Genetic counseling for breeders.

Prognosis

Deaf animals can live full, happy lives with appropriate management and training. Unilaterally deaf animals function nearly normally. The condition itself is not progressive or painful.

Affected Breeds (9)

Related Conditions

• Vestibular Disease
• Blue Eye Color
• Merle Coat Pattern