There's a lot of buzz in dogdom about selective hearing. This somewhat derogatory term applies to Chihuahuas who haven't yet mastered the recall, among other things. Unlike people, though, Chihuahua's don't reason and purposely decide to turn a deaf ear.
A combination of distractions, doing what they were bred to do, and often ineffective training makes some Chihuahuas appear stubborn. Instead of yelling at the top of your lungs, whisper, "cookie" and he'll instantly become a better listener.
But what if your formerly responsive Chihuahua is suddenly tuning you out? It's possible he may be experiencing hearing loss. Whether it's an easily remedied wax build-up or treatable ear infection, old age, or a congenital (present at birth) or acquired hearing loss, you'll need to do a little detective work to learn if your Chihuahua is hearing-compromised.
You can perform a simple at-home hearing test to get an idea of the degree of loss, then consult with your veterinarian for a professional Brainstem Auditory Evoked Response or BAER hearing test, which looks at brain activity caused when the ears register sounds.
Chihuahuas hearing versus humans
Chihuahua listens to things we never hear. Second, only to their phenomenal sense of smell, a Chihuahua's hearing is amazing! They can hear the bodily movements of termites in a wall and hear their owner's heartbeat from the other side of the room.
In fact, Chihuahuas' superior hearing has played a major role in thousands of years of success as a species. In the wild, if a Chihuahua or wolf couldn't hear the beating heart of their prey from a fair distance away, they would have no chance to catch it, thus wouldn't eat that day.
The sense of hearing is measured in frequencies or pitches, and humans, depending on their age, can hear sounds beginning at 20 hertz and ranging up to 12,000-to-20,000 hertz. In contrast to our seemingly limited spectrum of audible sounds, at least by canine standards, Chihuahua, depending on their breed and age, can hear in the range of 40,000-to-60,000 hertz.
Human and Chihuahua ears share similar anatomy of the middle and inner ear with an eardrum, which is known as a tympanic membrane and little bones in the inner ear called ossicles that vibrate sending signals to the brain via the auditory nerve. But, of course, Chihuahua ears are larger, and they also contain at least 18 muscles that control the pinna, or ear flap.
These muscles allow them to fine-tune the position of the ear canal, thus localizing sounds and hearing more accurately from farther away than a human ever could.
Chihuahuas with hereditary hearing loss
While it's normal for Chihuahua to be born deaf with closed ear canals, some Chihuahuas will remains deaf. It seems that congenital deafness is mostly genetic and, according to Stanley Coren, PhD., is associated with certain coat colors. A normal pup's ear canal opens 10-to-14 days after birth. If a puppy doesn't seem to hear by the time he's three weeks old, a BAER test should be administered, because it may take several weeks before a veterinarian or breeder recognize it.
At high risk of congenital hearing loss are Chihuahuas with a white coat with spots, or piebald, pure white, roan, and merle. A classic example of the piebald is the Dalmatian breed where 22 percent are born deaf in one ear, 8 percent are deaf in both ears, and 30 percent are affected with some level of a hearing deficiency.
What can affect hearing temporarily?
Dirty ears can affect hearing. Like people, Chihuahuas can get a wax build-up in their ears that impacts their hearing. Consult with your vet for the best ear cleaner to do the job at home or have your Chihuahua's ear cleaned in the vet's office. Ear infections can also cause a partial loss of hearing and often can go undetected until the infection blocks off a portion of the ear. Ear infections are treatable, and a trip to the vets and some aftercare at home will usually resolve the issue.
What can cause a loss of hearing?
When a condition reduces the diameter of the ear canal or blocks sounds from entering, partial or complete hearing loss is the result. Here are some of the most common causes of a hearing loss in Chihuahuas:
- Ear inflammation or infection, which can be caused by seasonal, food, or flea allergies, and promotes the growth of infectious bacteria and yeast.
- Ear mites.
- Toxic exposure.
- Blunt trauma to the neck, skull, or other body parts; for example, being hit by a car or kicked by a horse.
- Tumors that are cancerous or benign since the mass takes up space and exerts pressure on the inner ear structures.
- Glandular disorders like hypothyroidism contribute to abnormal nerve function.
Detecting hearing loss
Most likely, a loss of hearing in your Chihuahua will be apparent as you observe his day-to-day habits. Watch for these clues that hearing loss may have occurred and immediately consult with your veterinarian who will perform a physical exam using an otoscope to visualize the ear canal and eardrum for a preliminary diagnosis, which can be followed up with a BAER test for definitive diagnosis:
- You return home and your Chihuahua doesn't respond to the opening of the door or greet you as he always has in the past, but seems to respond only when he hears the vibrations of your footsteps on the floor.
- Your Chihuahua does not respond when you call his name, nor to other familiar sounds.
- Other pets in your home suddenly seem to be able to sneak up on your Chihuahua, encroaching on his personal space.
- When you stand in another room, out of sight, and make loud sounds like whistles, jingle keys, clap hands, or bang pots, your Chihuahua do not turn his head toward the sound.
Where to get a Brainstem Auditory Evoked Response (BAER) test
Many veterinarians offer the BAER test in their clinic, or they may refer you to a veterinary neurologist who administers the test. Also, mobile services are available; for example, Advanced Veterinary Mobile (Judy Pawlusiow, DVM) which operates in New York, New Jersey, Connecticut, Pennsylvania, New Hampshire, Massachusetts, Vermont, and Rhode Island.
Originally developed for humans, the BAER test measures how your brain processes the sounds you hear by detecting electrical activity in the cochlea and auditory pathways in the brain, in a similar way to an EKG, which detects the electrical activity of the heart. For Chihuahuas, it's the same test, and it takes about 10-to-15 minutes to complete. It's administered by placing tiny electrodes under the skin in the front of each ear, the top of the head, and one between the shoulders.
It is rare that a Chihuahua exhibits any pain during this procedure. Ears are tested individually with a stimulus click produced by the computer-directed into the ear with a foam insert earphone. The computer records the waveform responses consisting of peaks numbered with Roman numerals, starting at 1, indicating variations of hearing, to flatline, which indicates no response, or deafness. After the test, you get a printout of the results showing the recorded waveform; test results are confidential.
Is there any treatment for hearing loss?
Hearing aids for Chihuahuas have been developed after years of research, but the cost is prohibitive for many Chihuahua owners. Also, keep in mind, the chances of getting your Chihuahua comfortable with a foreign object in her ear may be slim to none in the case of many Chihuahuas. However, smaller Chihuahuas seem to tolerate hearing devices better than larger Chihuahuas.
Living with a deaf Chihuahua
Unless a Chihuahua was born deaf and has become used to living without hearing, a Chihuahua with acquired deafness will not be as responsive as a Chihuahua who can hear, for obvious reasons. However, other senses do kick in, and a deaf Chihuahua's sense of touch intensifies.
After the initial confusion, many deaf Chihuahuas live an excellent quality of life with families sensitive to their limitations. In many cases, a Chihuahua with total hearing loss will thrive; masters of adaptation that they are!
