Dog Cognitive Dysfunction

Veterinarian Reviewed on January 4, 2008 by Dr. Janice Huntingford

Dog Cognitive Dysfunction–Alzheimer’s in Animals

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Signs and Symptoms

Due to advances in veterinary medicine and the quality care of loving pet owners, dogs are now living longer than ever before. This also means that the incidence of geriatric-related illnesses and diseases has increased. As an animal ages, its internal organs and systems inevitably undergo changes and deterioration which can potentially lead to a variety of different health problems and medical conditions. One geriatric-onset medical condition that affects some senior dogs is canine Cognitive Dysfunction Syndrome (CDS). Similar to Alzheimer’s disease in humans, dog Cognitive Dysfunction Syndrome causes behavioral changes that are not a normal part of the aging process.

The various symptoms and behavioral changes that canine Cognitive Dysfunction Syndrome can give rise to fall into four general categories that can be abbreviated into the acronym DISH — disorientation, interaction changes, sleep changes, and house soiling. When a dog becomes disoriented, it may display a number of different behaviors including forgetfulness. A disoriented dog may stop responding to its name and once-familiar commands. An animal with this condition may also fail to recognize familiar people, such as family members, and familiar places like its own backyard. When a dog is suffering from disorientation, it may walk in circles, pace, or stare aimlessly at walls and objects. Becoming confused and lost in familiar places is also common and may lead to situations such as the animal becoming stuck behind furniture or trying to pass through an entry way at the hinged side of a door.

Social interaction changes resulting from this Alzheimer’s-type disease in dogs typically results in the afflicted animal no longer enjoying attention or being petted. Dogs with Cognitive Dysfunction Syndrome also tend to stop greeting visitors and family members and will walk away while in the midst of receiving attention. Depression is also common, as is the deterioration of social hierarchies in a multiple pet household. Sleep changes also arise as a result of dog cognitive problems. Typically, dogs with Cognitive Dysfunction Syndrome sleep less during the night and more during the daytime. Crying and pacing instead of sleeping are also common behaviors. With respect to the house soiling category of behavioral changes, previously house-trained dogs will begin to have accidents indoors, even if they have recently been outside. Animals with a cognitive disorder often forget to ask to be let outside and when they are outdoors, they will often forget why they are there.

If you observe your dog exhibiting any of the above warning signs, it’s vital to consult with a veterinarian immediately. A professional will be able to determine whether these behavioral changes are being caused by Cognitive Dysfunction Syndrome or a medical condition such as deafness, a thyroid disorder, a urinary tract infection, or a brain tumor. Once the cause of your pet’s symptoms has been identified, a proper care regime and treatment plan can be developed to help make your dog’s senior years as comfortable and as enjoyable as possible.


Unfortunately, there is no special test or procedure that can be used to diagnose canine Cognitive Dysfunction Syndrome. Furthermore, the clinical signs of this disorder will not show up during a physical examination. For these reasons, the observations that you, as the pet owner, make at home will be very important with respect to a veterinarian’s diagnosis. If you have been noticing behavioral changes in your pet, it’s a good idea to write down what you have observed and when and where the behaviors are exhibited. This will be of great help to your veterinarian when it comes to identifying the cause of your pet’s symptoms.

In addition to taking a complete medical and behavioral history of your pet and speaking to you about the behaviors observed in the home environment, a veterinarian will also conduct a thorough physical examination. Rather than to identify the presence of Cognitive Dysfunction Syndrome, this step is more for ruling out other medical conditions that could potentially be causing the observed symptoms and warning signs. Blood tests and urinalysis will also likely be performed in order to rule out other causes. Depending upon the symptoms displayed by the canine patient, other diagnostic tests may be performed, such as analysis of cerebrospinal fluid or a neurological exam. Once underlying diseases have been ruled out and your pet’s symptoms and behaviors have been confidently attributed Cognitive Dysfunction Syndrome, treatment can be discussed and pursued.


It can be heartbreaking and upsetting to watch your dog grow confused and lose the personality it’s had all through its life. The behavioral changes caused by dementia and disorientation can not only disrupt your pet’s life, but the lives of everyone in the household. If your dog is suffering from Cognitive Dysfunction Syndrome, understanding what this disorder involves may at least help you to comprehend the situation and will hopefully help you to provide the best care possible for your beloved pet.

Canine Cognitive Dysfunction Syndrome refers to the typically gradual, geriatric onset of one or more behavioral changes not caused by an illness or medical condition. Similar to Alzheimer’s disease in humans, cognitive dysfunction in dogs involves the deterioration of a canine’s brain and nervous system. It leads to the loss of cognitive abilities and functions, which then triggers behavioral changes. The changes that occur as a result of cognitive dysfunction are not part of the normal aging process and can be very disruptive and upsetting for the afflicted animal and all members of the household. Since onset of these behavioral changes is usually gradual, they may first appear mild and grow progressively more noticeable and severe over time.


The underlying cause of canine Cognitive Dysfunction Syndrome is unknown, leaving it a mystery as to why one dog develops this disorder when another does not. However, while the actual cause of this syndrome remains unknown, certain physiological changes that occur with the onset of this condition have been observed and identified.

As mentioned previously, canine cognitive dysfunction involves the deterioration of a dog’s brain and nervous system. More specifically, physical changes in the animal’s brain and brain chemicals occur, leading to the degeneration of cognitive abilities. Autopsies conducted on dogs with this condition have revealed the presence of brain lesions, very similar to those found in human brains affected by Alzheimer’s. Several occurrences that are thought to lead to the development of Alzheimer’s in humans are also thought to contribute to Cognitive Dysfunction Syndrome in dogs. Some such occurrences include the accumulation of B-amyloid proteins and the increased activity of monoamine oxidase-B.

With respect to B-amyloid proteins, a certain level of accumulation is perfectly natural. With age, these nerve-damaging proteins accumulate and form a plaque-like substance. This plaque then inhibits brain function by disrupting the organ’s ability to transmit signals. A dog with Cognitive Dysfunction Syndrome has excessive amounts of this plaque, leading to severe cognitive degeneration. However, why excessive buildup of these damaging proteins takes place, and therefore what actually causes cognitive dysfunction, remains unknown.


While there is no cure available for canine Cognitive Dysfunction Syndrome, there are a number of treatment methods that can reduce symptoms and greatly improve your dog’s quality of life. Medication is one treatment option that involves the administration of a prescription drug which increases levels of the neurotransmitter dopamine. While it can take up to two months for a dog to show improvement under this form of treatment, such drugs have been known to temporarily reverse some of the changes caused by this syndrome and to increase comfort and happiness.

In addition to drug therapy, there are several other forms of treatment that are known to be quite successful. Antioxidant treatment and supplements of omega-3 fatty acids have both proven effective for some dogs with cognitive dysfunction. B vitamin supplementation is also a safe and effective way of reducing the symptoms and behaviors caused by Cognitive Dysfunction Syndrome. The added benefit of the three previously mentioned treatments is that they are more natural than drug therapy.

While using medication or more natural forms of treatment, there are also other steps you can take to improve your geriatric pet’s quality of life. For example, providing mental stimulation will help all senior dogs to stay healthy and enjoy life. Some forms of mental stimulation include playing with your dog, taking it for walks, petting it, and talking to it. Another step you can take to make life easier for your dog is to keep your yard fenced and to use a leash when walking your dog. This will prevent your senior dog from wandering away and becoming lost or confused. In addition, it’s a good idea to minimize stress by sticking to a daily routine and rearranging furniture as little as possible. These steps will help to improve the quality of life for all senior pets, and will especially have an impact on the comfort and happiness of dogs suffering from canine Cognitive Dysfunction Syndrome.

See Also Caring for Aging Dogs

Read also: Dog Mast Cell Tumors
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Our Expert

Dr. Janice Huntingford
Janice Huntingford, DVM, has been in veterinary practice for over 30 years and has founded two veterinary clinics since receiving her Doctor of Veterinary Medicine at the Ontario Veterinary College, University of Guelph. She has studied extensively in both conventional and holistic modalities. Ask Dr. Jan

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