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Canine Cognitive Dysfunction

Cognitive behavior includes spatial orientation; problems with memory, learning, housetraining; and recognizing and reacting to human family members.

Pet owners have long been frustrated by age-related behavior changes, including house-training problems, apparent memory loss, disorientation, confusion, staring, wandering, getting stuck in corners, sleep disturbances (waking at the wrong time, sleeping unusually deeply, night pacing), restlessness, barking, separation anxiety, panting, drooling, obsessive licking, etc. Progression of clinical signs is very gradual; most owners fail to recognize the early stages.

These changes are often written off as being due to normal aging. A recent study at the University of California School of Veterinary Medicine demonstrates how common these observations are: out of 69 dogs participating, 32% of the 11-year old dogs were affected by this syndrome and 100% of the dogs 16 years of age older were affected.

Still, the high frequency with which the syndrome is seen in older dogs does not make the behavior normal. Other studies have shown that dogs affected by this syndrome show deposition of amyloid (a protein) in their brains in patterns very similar to the amyloid plaques found in the brains of human Alzheimer’s patients.

In addition, cognitive dysfunction is often associated with the depletion of dopamine, a neurotransmitter.


Treatments that may help improve cognitive dysfunction include L-Deprenyl, dietary changes, and environmental enrichment.

L-Deprenyl (Anipryl)

L-Deprenyl helps prolong dopamine activity. This may account for part of its efficacy in treating cognitive dysfunction. In addition, since dopamine breakdown results free radicals, L-Deprenyl also helps reduce amounts of free radicals in the brain.Of the 69 dogs mentioned in the above University of California study, approximately 76% showed improvement on L-Deprenyl after one month of therapy. Some dogs improved in the first few days or weeks; some dogs did not show improvement until the second month. Often dogs continued to improve during the first three months. Anecdotally, the earlier L-Deprenyl is started, the better the result.

When using L-Deprenyl to treat cognitive dysfunction, if no improvement is seen after the first month, your veterinarian may recommend doubling the dose for an additional month before deciding the drug may not be useful in that particular pet.

Dietary Changes

Hill’s Prescription Diet B/D contains antioxidants (mixed tocopherols, vitamin C, beta-carotene, carotenoids, and flavenoids), mitochondrial cofactors, and omega-3 fatty acids (EPA, DHA). The diet has been shown to improve the performance of a number of cognitive tasks, when compared to older dogs on a non-supplemented diet. Improvements have been seen as early as to 2 to 8 weeks after the onset of therapy.

Environmental Enrichment

Just because they’re old doesn’t mean your dogs can’t learn new things. Use their intelligence to improve the quality of their lives.

If your old dog’s vision is still good, teach signals. This will serve as a back-up if hearing fails, which it often does. Signals are fun for dogs and are a more natural language for them than words.

Grooming (touch) will help your dog cope with vision and hearing loss. Your touch will help guide your dog.

In a laboratory study of older dogs over a 2-year period, environmental enrichment (e.g., housing with another dog, playing daily with toys) was shown to be effective tool for task learning. In fact, the combined effect of a special diet and enriched environment provided the greatest improvement in learning ability when compared to the dogs who did not have either dietary or environmental enrichment.

With proper care, older dogs can be helped to manage the cognitive changes they will encounter. Old age is not a disease.


By Wendy C. Brooks, DVM, DipABVP

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