Is your dog going deaf? Perhaps he’s just getting older, but there are other causes of hearing loss in canines, so it’s always a good idea to have him checked out by a veterinarian.
When people find out their dogs have hearing loss, they often feel concerned. But in most cases, the cause is either treatable or simply a normal part of aging, and not harmful or fatal to the dog. This article will discuss hearing loss and deafness in dogs, along with treatments to try with the guidance of your veterinarian.
In clinical practice, there are five common causes of hearing loss in dogs.
1. Normal aging
This type of hearing loss is often termed “sensorineural hearing loss”. It results from missing or damaged sensory cells (hair cells) in the cochlea of the inner ear, and is usually permanent. Damage to the auditory nerve in the brain can cause neural hearing loss, which is also usually permanent. Hearing tests using an electroencephalogram (EEG) are often recommended, along with a brain stem auditory evoked response (BAER) test. I typically notice age-related hearing deficits or total deafness beginning late in a dog’s life, typically at 12 to 15 years of age. I usually find the hearing loss is not complete, as the dog may hear certain high-pitched such as a doorbell ringing or a fork hitting a metal food bowl.
“Sensorineural hearing loss” results from missing or damaged sensory cells (hair cells) in the cochlea of the inner ear, and is usually permanent.
Before diagnosing “old age” as the cause of a hearing deficit, it is important to rule out the other causes of hearing loss discussed below. These other issues are usually treatable if they’re diagnosed early and treated properly.
2. An ear infection involving both ears
Often, people don’t even know their dogs have ear infections. A physical examination usually reveals a large amount of debris in the vertical ear canal. This debris is placed on a slide and examined microscopically. Usually, yeasts or bacteria are seen, although ear mites are occasionally found.
Once the proper diagnosis is made, the correct treatment can be chosen to cure the infection. If the infection has caused hearing loss, the deafness is usually temporary and resolves with treatment. Dogs with extensive ear infections may need repeated treatments, which usually involve flushing the ear debris (often under sedation) and applying the appropriate medication (natural or conventional). Infections that do not resolve with treatment may have an underlying cause such as allergies, thyroid disease, or adrenal disease.
If the infection has caused hearing loss, the deafness is usually temporary and resolves with treatment.
Keep in mind that the ears may sometimes look clean, yet there’s a deeper infection down in the horizontal part of the ear canals. These dogs often require sedation or anesthesia in order to adequately examine the ear, collect specimens for diagnostic testing, and for treatment. Also, know that ear treatment medication rarely causes hearing loss. I have only seen this once in practice, and the hearing loss resolved shortly after it began.
3. Hypothyroidism or low thyroid disease
Hearing loss as the sole sign of hypothyroidism is rare, because thyroid hormones affect all body systems (including the nervous system). But it is nevertheless important to make sure a dog with hearing loss is not suffering from a thyroid problem. Blood testing should be done for every dog with hearing loss and should include a complete blood count, organ profile, and thyroid testing (total T4 and free T4.) Even dogs with borderline “normal” thyroid hormone levels should be treated for at least one to two weeks to see what extent the hypothyroidism is contributing to their hearing loss.
4. Cognitive disorder (doggy Alzheimer’s)
Hearing loss can occur due to cognitive disorder. I first “discovered” this condition, which is somewhat related to aging, almost 30 years ago when I first graduated from veterinary school. I noticed a number of aged dogs acting “senile”. Many of these senile dogs also had hearing loss and where hypothyroid. They responded partially to thyroid supplementation. An article I read while investigating these cases (written in the 1970s) suggested that senile dementia was a possible “new” condition in older dogs. Supplementation with phosphatidylcholine was “curative” for these senile pets.
Again, I must stress the importance of a thorough examination and lab testing to look for underlying causes of any disease or symptoms, including deafness, so those causes can be treated.
For dogs with cognitive disorder, treatment with phosphatidylcholine, antioxidants, fatty acids, ginkgo biloba, and other supplements, returns most to normal function. However, true cure is unlikely, as dogs with cognitive disorder usually regress and act senile if treatment is stopped.
5. Organic brain disease, such as GME, encephalitis or a brain tumor
Usually, dogs with organic brain disease have other clinical signs besides hearing loss, such as seizures, depression, or changes in cranial nerve function (blindness, paralysis, circling, etc.). These dogs must have advanced imaging done (CT, MRI, etc.) in order to properly diagnose and treat the underlying problem. These causes of hearing loss are serious and expensive to diagnose and treat — but fortunately, they are very rare.
Deafness in dogs can have a variety of causes and treatments. In many cases, it results simply from “old age” and treatment is neither needed nor effective. However, it’s important to rule out other conditions rather than let a dog that could be cured remain deaf for the rest of his life.