Largely thanks to you, your cat has always enjoyed a safe and apparently happy life. And largely thanks to you, it can continue to do so, even though it has become, for one reason or another, totally deaf. Indeed, Dr. James Flanders observes, life can become quite comfortable for a cat that is no longer startled by the yapping of a neighbor’s dog or the harsh snorting of your vacuum cleaner.
If your cat has become deaf, Dr. Flanders advises, the first thing you’ll want to do is make it a strictly indoor animal, out of harm’s way when it comes to sounds that it can longer perceive and respond to — the roar of an oncoming car, for instance, or the stealthy movements of an approaching enemy.
Indoors, he points out, you must always be aware of your cat’s hearing loss and adjust your behavior accordingly. He suggests the following: “Avoid startling the animal. Never approach it from behind without signaling your approach. Clap your hands sharply or stomp on the floor. The vibrations will let the cat know that you’re nearby. If it’s asleep on the sofa and you want it to wake up, move a pillow. The cat will pick up those vibrations, too.”
Perhaps your cat has been trained to respond to verbal cues, such as “Here, kitty, kitty.” If so, you’ll have to replace such verbal communication with visual commands — a hand signal, for example, to announce that dinner is served. Or you may be able to communicate with the cat by flicking a light switch on and off.
A wide range of afflictions can cause discomfort; some may even lead to deafness. Here's how to protect your cat.
Among a normal, healthy, and properly cared-for cat’s many distinctive attributes is its astoundingly acute sense of hearing. While the human auditory system is capable of detecting sounds ranging in frequency up to about 20,000 vibrations per second, cats typically can sense sounds pulsating at 60,000 vibrations per second or greater. This impressive acoustic sensitivity has been honed over the ages to serve a cat in countless ways—signaling the stealthy approach of a dangerous predator, for example, or detecting the underground movement of a burrowing rodent.
Although most cats will go through life without experiencing a serious problem with their ears, owners should know that a variety of conditions—including congenital defects, infections, trauma and age-related changes—can be extremely painful and may compromise an animal’s hearing. Most feline ear disorders are readily treatable and will not result in permanent hearing loss, notes James Flanders, DVM, an associate professor of surgery at Cornell University’s College of Veterinary Medicine. However, some conditions may render a cat partially or totally deaf, especially if they remain unrecognized and untreated.
A cat’s ears, like those of other mammals, are made up of three structural areas: the outer ear, middle ear and inner ear. The outer ear consists of the external earflap (pinna), and the ear canal—a narrow tubular passage through which sound vibrations enter the ear from the outside environment.
The middle ear contains the eardrum, a taut membrane that vibrates according to the incoming sound waves, and the auditory ossicles, small bones that transmit the eardrum vibrations to the inner ear. And the inner ear—located deeper within the skull—contains the cochlea, a snail-shaped structure containing nerve endings that receive the vibrations and passes them along to the brain, thereby enabling a cat’s hearing. The inner ear is also the site of the vestibular system, a complex arrangement of nerves and receptors that govern a cat’s sense of balance.
Some feline ear abnormalities are genetically transferred from parents to offspring. Among these is an inherited condition known as “fold-ears,” in which the tip of a cat’s pinna is bent sharply either toward or away from the skull. This bizarre condition is not often associated with hearing loss. However, cats whose ears are unusually distorted in this manner frequently experience accompanying skeletal problems that may have troublesome consequences.
Another primarily heritable abnormality, says Dr. Flanders, is atresia—a defect in the development of the ear canal that may result in partial or total obstruction of the channel. “In this condition,” he points out, “a wall develops in the ear canal that makes it difficult or impossible for sound to reach the cochlea. It’s sometimes operable, and if this wall can be removed, hearing can potentially be restored.”
Some cats are born deaf, and the disability cannot be corrected. Due to an anomaly in their genetic makeup, white cats with blue eyes are at greatest risk for congenital deafness. Indeed, says Dr. Flanders, “About 80 percent of white cats with two blue eyes will start to show signs of deafness when they are about four days old as the result of cochlear degeneration.”
The great majority of feline ear disorders are acquired. A cat that fights a lot or is in the habit of scratching its ears excessively, for example, might experience hematoma, a collection of blood from broken vessels that collects between the skin covering the ear and the underlying cartilage. Cats may also be afflicted by various polyps (small growths protruding from the surface of a mucous membrane) and squamous cell carcinoma—a cancer that can emerge on the ear tips and is especially common in cats that are frequently exposed to harsh sunlight.
Owners should also keep in mind that a cat’s eardrum thickens with age. Thus, hearing difficulties and potential deafness are often found in geriatric cats. Moreover, deafness can occur as a side effect of various medications—certain antibiotics or diuretics, for example.
Among all acquired feline ear conditions, Dr. Flanders notes, the most common by far is otitis externa, an infection of the outer ear canal. This disorder results from infestation of the ear canal with infectious agents, usually ear mites.
Otitis externa is most prevalent in cats that are especially susceptible to seborrhea, a skin ailment marked by excess oily secretions from the sebaceous glands. This results in the accumulation of surplus ear wax in which invading mites, bacteria, and other organisms can flourish. If otitis externa is not appropriately treated, the infection can migrate to the middle ear, where it is termed otitis media, and to the inner ear (otitis interna). In the most severe cases, the ear drum and inner ear can be irreparably damaged, resulting in deafness and—because of the condition’s impact on the vestibular system—an acute disturbance of balance on the affected side or sides.
Reducing the Risk
Most feline ear disorders, including otitis externa, can be treated with medicine, says Dr. Flanders, although surgery may sometimes be the only option. Unfortunately, deafness in one or both ears is most often a permanent condition.
A few simple measures, he points out, will substantially reduce the chances that a cat will experience a serious ear disorder. He advises the following:
If you observe your cat persistently scratching at its ears, do not probe into them to find the cause. Instead, consult your veterinarian as soon as possible.
By Tom Ewing