Deafness in Dogs

 

Deafness refers to the lack (or loss) of an animal's ability to hear -- this can either be complete or partial loss. If the dog is deaf at birth (congenital), it will be very apparent to you at a young age. More than 30 breeds of dogs have a known susceptibility for deafness, including the Australian shepherd, Boston terrier, cocker spaniel, Dalmatian, German shepherd, Jack Russell terrier, Maltese, toy and miniature poodle, and West Highland white terrier. Typically, it is more common in senior dogs.

 

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the petMD health library.

 

Symptoms

 

• Unresponsive to everyday sounds
• Unresponsive to its name
• Unresponsive to the sounds of squeaky toys
• Not woken by a loud noise

 

Causes

 

• Conduction (sound waves do not reach the nerves in the ear)
  • Inflammation of the outer ear and other external ear canal disease (e.g., narrowing of the ear canal, presence of tumors, or ruptured ear drum) 
  • Inflammation of the middle ear 

 

• Nerve
  • Degenerative nerve changes in elderly dogs
  • Anatomic disorders — poor development (or lack of development) in the part of the ear that contains the nerve receptors used for hearing; the condition leads to fluid buildup in specific areas of the brain and damages the part of the brain involved with hearing
  • Tumors or cancer involving the nerves used for hearing
  • Inflammatory and infectious diseases — inflammation of the inner ear; canine distemper virus may cause alterations in hearing, but not complete deafness; inflammatory masses that develop in the middle ear or eustachian tube
  • Trauma

 

• Toxins and Drugs
  • Antibiotics
  • Antiseptics
  • Chemotherapy drugs
  • Medications to remove excess fluid from the body
  • Heavy metals such as arsenic, lead, or mercury
  • Miscellaneous — products used to break down waxy material in the ear canal

 

• Other risk factors
  • Long-term (chronic) inflammation of the outer, middle, or inner ear
  • Certain genes or white coat color

 

 

Diagnosis

 

A complete history of the dog, including any drugs that may have damaged the ear or caused a chronic ear disease, is completed by the veterinarian. Early age onset usually suggests birth defects (congenital causes) in predisposed breeds. On the other hand, brain disease is a slow progressive disease of the cerebral cortex, usually caused by senility or cancer -- making the brain not able to register what the ear can hear. Bacterial cultures and hearing tests, as well as sensitivity testing of the ear canal, may also used to diagnose the underlying condition.

 

Treatment

 

Unfortunately, any deafness present in the dog at birth (congenital) is irreversible. If it is caused by an inflammation of the outer, middle, or inner ear, medical or surgical approaches may be used. These two methods, however, are dependent on extent of disease, bacterial cultures, sensitivity test results and X-ray findings.  Conduction problems, in which sound waves do not reach the nerves of hearing, may improve as inflammation of the outer or middle ear are resolved. Hearing aids can also sometimes be used for dogs.

 

Living and Management

 

Your dog's activity should be reduced to avoid any any possible injury (e.g., a deaf dog cannot hear an approaching car). The home environment may also need to be controlled for the dog's protection.

 

The veterinarian will need to see your dog weekly and treat it for the ear disease, or until the condition is resolved.