Adrienne is a certified dog trainer, behavior consultant, former veterinarian assistant, and author of Brain Training for Dogs.
Sensory decline in old dogs is a normal part of the aging process. Knowing what to expect with an aging dog allows dog owners to better understand the aging process in their senior dogs. Just as it happens in humans, as the years go by, sooner or later, dogs will undergo several physical, sensory and mental changes that are simply due to the wear and tear of life.
It's normal for old dogs to slow down, stiffen and turn gray. We all know that. The rate at which this happens though may vary from breed to breed and dog to dog. More than breed though, the rate of aging in dogs appears to be size-dependent, meaning that in general, smaller dogs will live longer than larger ones, and the larger ones will live longer than the giant ones.
Even among dogs of the same breed, and therefore, dogs of the same or similar size, there are many individual factors. This happens as well in humans, after all. There are 70-year old seniors in nursing homes or depending on assisted living and then there are 70-year old seniors still running marathons!
The aging process can therefore affect dogs at different rates based on individual factors such as genetics, diet, exercise,and level of care provided. There is such a thing as aging gracefully in dogs and this is often the result of a winning combination of good genes and a good environment.
Stiffening, going gray, slowing down, cognitive changes are recognized by most dog owners dog owners. However, signs of sensory decline in old dogs are often missed or confused for behavior issues.
Changes to the Dog's Sense of Hearing
Your dog's ears have been working as a pair of sentinels for many years, twitching and turning to capture the slightest sounds. It's inevitable that, as dogs age, the nerve cells of the ear, along with other parts of the dog's hearing apparatus start to degenerate.
This specific type of loss of nerve function is referred to as neurogenic deafness and it's the most common cause of deafness in aging dogs, explains veterinarian Dr. William D. Fortney.
This degeneration causes the ear drum to lose its capacity to easily respond to vibrations as it used to. This results in hearing loss. In one study, about 48 percent of dogs over the age of 12 manifested some significant deficits in their ability to hear, and that included deafness. By the age of 16, 97 percent of dogs showed significant deficits and that included complete deafness.
Loss of hearing can cause aging dogs to feel more vulnerable and this may lead to behavior changes as well. Some dogs may get startled more easily when touched (because they missed the auditory cues signaling your closer presence or the closer presence of another dog). Other dogs may stick closer to their owners, almost as if they feel more vulnerable and start to depend on their owners as their "hearing aids."
If your dog's sense of hearing seems to be declining, see your vet before assuming it's just a part of aging. You may first want to rule out other possible causes for loss of hearing which might be temporary such as exposure to loud noises, accumulation of ear wax or a side effect from the use of ototoxic drugs.
What you can do: Some dogs owners may find the use of a vibrating collar helpful when they need to get their dog' attention. For instance, you can use the collar to alert your dog when you are coming through the door so he can get up and come greet you rather than being startled by your abrupt presence in the house.
Owners of dogs who have still some retained hearing, may find it helpful to use a high-frequency dog whistle as a temporary aid, at least until the dog's ultra-high frequency sound receptors are also lost, further suggests Dr. Fortney.
Training is always beneficial to dogs, even the older ones.Dogs love consistency and continuing your dog's training makes for a calmer and more confident dog. In this case, taking some time to teach your dog to respond to visual cues for rewards rather than verbal ones can prove beneficial.
Changes to the Dog's Sense of Vision
Just as in humans, dogs are prone to vision changes as they age. You won' t ever find Rover wearing thick glasses to read the newspaper, but you might find him bumping into things or not being able to discern things as he used to before.
Aging brings several changes to a dog's eyes. First of all, as the years go by, the pupils may no longer expand and contract as well as before in response to light and dark. Therefore, you can expect your older dog to have a harder time seeing in dark or in very bright conditions due to this loss of elasticity in the lens of the eye.
Also, regular exposure over the years to ultraviolet light ends up having a cumulative effective causing damage to the eye's lens. As dogs get older, they therefore tend to develop a hardening of the lens in their eyes. Expect to see a slightly opaque, grayish-blue hue when you look into your dog's pupils. This condition is known as nuclear sclerosis, also known as lenticular sclerosis. Despite the cloudy appearance, this condition though doesn't typically cause vision impairment.
However, there are several other eye conditions affecting old dogs which may lead to vision loss. Cataracts and glaucoma are both vision-impairing conditions. Cataracts are cloudy or opaque areas in the lens of the eye which may appear as "crushed glass." These areas may impair vision because they change the ability of light being able to pass through the retina.
Glaucoma, on the other hand, can cause the rapid onset of cloudy, blood-shot eyes, dilated pupils and a bulging appearance. Glaucoma is a medical emergency, because it can cause vision loss due to increased pressure in the eye.
A study has shown that 41 percent of dogs over 12 years old had some degree of vision loss, and by the age of 16, 68 percent of dogs are affected.
What you can do: If your dog appears to not see well as before, see your vet, especially if the loss of vision seems to have occurred suddenly or if there are other symptoms such as squinting, redness, bulging of the eye. Some eye conditions need to be seen on an emergency basis to prevent irreversible loss of vision.
If your dog's vision is declining, there are several things you can do to help your dog. For instance, now is not the time to re-arrange all your furniture. Your dog needs to navigate based on his memory and other senses.Try to keep everything the same so your dog won't be bumping into new things, and if you need to move furniture around limit to moving only one piece at a time. Guide your dog on leash around the new furniture so your dog has a change to learn about its new location.
You will also need to be your dog's ambassador when people ask to pet him from now on. If your dog was standoffish prior to losing his vision you may want to use great caution. Blind dogs can startle and even may manage to snap. Have the person alert your dog by speaking to him and allowing him to sniff his hand before any petting take place just to give your dog a head's up.
On walks, make sure your dog remains at your side rather than in front of you. You may want to skip the retractable leash if that's what you used before. Use a 4 or 6-foot one instead.
If you have a large yard or acreage, you may find it helpful installing some wind chimes, so your dog can find his way back in the home. Letting him wear a bell on his collar, on the other hand, can help you easily locate him if he manages to get lost.
If you own other dogs or pets, letting them wear a bell as well on their collars can help your dog be more aware about their whereabouts. If you need to approach your dog, or want to pet him, let him know of your intentions by talking to him first.
Changes to the Dog's Sense of Smell
Your dog's sense of smell if his strongest sense, but even a dog's sense of smell can be impacted by the effect of wear and tear. The medical term for loss of smell is "anosmia" and it can be just temporary or permanent. Fortunately, in most cases, in dogs the issue tends to be more often temporary, rather than permanent, explains veterinarian Dr. Pete.
For example, an infection of the dog's nasal passages causing inflammation to the membranes responsible for carrying smell sensors may be a culprit, but so can an obstruction of the nasal passages. In some cases, loss of smelling ability may happen if something toxic or caustic happens to scar the dog's nose. Once these issues are addressed, the dog's sense of smell is likely to return.
As dog age though, their sense of smell may be diminishing, and any added issues affecting the dog's nasal passages may exaggerate this. Older dogs are more prone to develop polyp or tumors in their nose. Both of these can trigger dogs to breathe through their mouths which can impact their ability to smell.
Not to mention that older dogs are likely to have bad teeth, and when the roots of the upper teeth go bad, they can cause an infection affecting the dog's nasal passages, further explains Dr. Pete. In some cases, loss of smelling capability can occur due to a brain issue / tumor which the incidence of such conditions occurring get higher as dogs age.
What you can do: consult with your vet about your dog's loss of sense of smell. As mentioned, in some cases, there may be medical causes behind it.
Changes to the Dog's Sense of Taste
A dog's sense of taste is very closely associated with his sense of smell. If you ever had a cold, you probably already know all about it. Eating doesn't feel much appealing when your nose is all clogged up!
Humans have many more taste buds than dogs do, but dogs have a powerful nose which helps a whole lot. Many dog owners report that their senior dogs become more finicky in their eating habits as the years go by. Changes in the sense of smell and taste is problematic in older dogs because it lowers their interest in food which can cause weight loss.
While a loss of interest in food can be part of aging, a loss of appetite in old dogs can be due to other medical problems.
For instance, most old dogs have to certain extent some level of periodontal disease, which can cause pain when eating due to the presence of an abscess or infection. It's therefore important to see the vet before assuming a senior dog is not eating due decreased ability to taste and smell food.
What you can do: see your vet to play it safe. Your vet can check for any underlying medical problems that may cause a decrease in eating such as cancer cachexia or metabolic issues.
If your dog checks out fine and has a good bill of health, consider increasing the palability of the foods you are feeding. Warming up food is often a great way to make food more palatable. Your vet may carry a line of products suitable for older dogs that are particularly palatable.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2017 Adrienne Farricelli
Adrienne Farricelli (author) on December 09, 2017:
Suhail, I was writing about this because my dogs are getting older and am trying to learn as much as possible what they are going through. Both my dogs already have the cloudy appearance of their lens. Your dog is in great hands having a dedicated owner like you!
Suhail Zubaid aka Clark Kent from Mississauga, ON on November 26, 2017:
I am bookmarking this superb article that is going to be a reference source for me perhaps 3-4 years down the road.
Suhail and my dog