What is cognitive dysfunction and how is it diagnosed?
Senior pet cognitive dysfunction refers to age-related changes in cognitive ability. Changes in cognition can occur at the same time as other medical disorders.
If your dog or cat has one or more of the signs below, it is important to rule out possible concurrent conditions before diagnosing cognitive dysfunction. Both medical and behavioral assessments are important in determining the cause of each sign.
The acronym DISHAA is used to describe the signs associated with cognitive dysfunction. DISHA refers to the following (with specific signs):
- Disorientation: Getting lost in familiar areas, not recognizing familiar people, and going to the wrong side of the door.
- Interactions: Changes in social interactions with household people and pets; becoming more clingy, becoming reclusive, irritability when approached.
- Sleep-wake cycle changes: Increased sleeping during the day, pacing and restlessness at night.
- House soiling, learning and memory: Soiling in atypical or inappropriate locations, soiling immediately upon returning to the house from the yard. You may notice your pet does not respond to previously learned behavioral cues. Aging pets may not adjust to changes (new schedules) as quickly as when they were younger.
- Activity level changes: Showing a reduced interest in play, difficulty settling, wandering or pacing, engaging in repetitive behaviors such as licking.
- Anxiety: Pets may become frightened of new stimuli, develop phobias related to thunderstorms, or become less tolerant of being left home alone (separation anxiety).
At what age might cognitive decline begin?
In one study, 28% of owners with dogs aged 11 to 12 reported that their dog exhibited at least one DISHAA sign. That number increased to 68% of owners with dogs aged 15 to 16. Research has shown after 7 years of age, your dog may not learn a new task as quickly and, more importantly, she may not remember as well.
Similarly, 35% of owners of cats aged 11 to 15 reported at least one sign of cognitive decline, rising to 50% in cats over the age of 15. Treatment options for slowing or reversing cognitive dysfunction are most effective with early disease detection.
Report any of these signs to your veterinarian immediately.
Do pets get Alzheimer’s?
Dogs and cats develop brain changes and lesions like those associated with Alzheimer’s disease in people, though the disease is not identical. As in people with Alzheimer’s disease, cognitive dysfunction is progressive, and not reversible.
Can behavior problems in senior pets be treated?
In many cases, the answer is yes. The first step in treating a pet, regardless of age, is to have a full medical and behavioral assessment completed. The diagnosis will guide the treatment of both the underlying medical conditions and the behavioral conditions. Treatment of behavioral conditions for pets of any age typically includes adjustments to the environment, behavior modification and, in some cases, psychotropic medication.
You may need to continue aspects of the behavioral treatment program even when medical conditions are well controlled. For example, medical conditions that trigger an increase in thirst may require you to continue to take your dog out to eliminate more often or provide an indoor toilet area; otherwise, house soiling may persist. Aging cats may need additional litter boxes to ensure they always find a clean box in an easily accessible area. For further information, see the handout “Cat Behavior Problems: House Soiling”.
Are there treatments that can improve the signs or slow the progress of brain aging?
Treatments have been designed to slow the progress of cognitive dysfunction. Some treatments are aimed at reducing the formation of beta-amyloid, a protein that binds together and blocks normal brain function. Additional treatments aim to improve declining cognitive function by reducing brain cell (neuron) loss, scavenging free radicals (a normal by-product of cell metabolism that also contribute to cellular breakdown), or affecting certain neurotransmitters (brain chemicals like dopamine) involved in cognition and other brain functions.
The medication selegiline (Anipryl® Pfizer Animal Health) has been licensed for the treatment of cognitive decline in dogs in North America. It is classed as a monoamine oxidase B (MAO-B) inhibitor and may enhance the function of neurotransmitters such as noradrenaline and dopamine. Selegiline may also reduce free radical damage in the brain and function as a neuroprotective drug. Many of the signs listed above (DISHAA) may be improved by treatment with selegiline.
For dogs, special diets are available. Hill’s Prescription Diet B/D is designed to protect against and possibly reverse damage due to toxic free radicals. The food is enhanced with a variety of antioxidants, including vitamin E, selenium, vitamin C, and fruits and vegetables. Hill’s B/D diet has been shown to improve learning ability and memory in senior dogs and improve the signs of DISHAA. Purina Pro Plan Bright Mind is a non-prescription diet designed to support cognition in dogs.
"Research is ongoing in this area."
Nutraceuticals are food-based products that may slow brain aging and reduce signs of cognitive dysfunction, though research is limited (see handout “Behavior Counseling - Complementary Treatments”). Products like: Denamarin®, Denosyl, and Novifit® contain SAMe; Neutricks® contains apoaequorin; and Senilife® contains Ginkgo biloba, phosphatidylserine, and a combination of antioxidants. You can discuss these products with your veterinarian.
Research is ongoing in this area. Drugs that improve circulation to the brain and decrease the chance of blood clots (infarcts) show some promise. Propentofylline is licensed for use in some countries outside North America. It is believed to improve blood flow in the area of the brain responsible for cognition (cerebrum).
Research has also shown that a specific type of brain activity (cholinergic transmission) can be affected in elderly pets, so veterinarians will avoid drugs that negatively impact this activity, where possible. Drugs that positively affect this brain activity may soon be on the horizon.
Finally, for treatment of specific signs such as anxiety disorders and altered sleep-wake cycles, medications and natural therapeutics may be useful. Special caution and consideration to side effects should be given when medicating or supplementing elderly pets.
Is there anything I can do to help my pet live a longer and healthier life?
In addition to finding the right diet for your pet’s age and health, ensuring your pet is not overweight can have significant health benefits.
Environmental enrichment is very helpful for maintaining brain health (the concept of “use it or lose it”). Continuing to provide your pet with physical exercise, play sessions, new toys, and even new training can all help enrich the lives and brains of our older pets.
Exercise and enrichment programs can be modified to suit the physical and behavioral needs of your senior pet. For example, physical exercise might need to be limited to short walks to sniff around the neighborhood.
Is there anything else I can do to help my pet live happily in its senior years?
Your senior pet may need more frequent access to appropriate bathroom areas. Dogs benefit from more frequent trips outside, or access to a suitable indoor potty area. Be sure your cat has a clean litter box that is easy to access. Some cats are less flexible as they age. Consider providing an extra-large litter box with low sides, and ample room to turn around.
If your floors are slippery, runners and floor coverings can be used to provide traction. If your dog or cat enjoys sharing furniture with you, provide a ramp or portable steps to allow her to easily climb up. When pets begin to lose vision, they benefit from additional lighting or aroma cues to help them navigate the home. Most importantly, continue to find ways to do things you and your pet enjoy doing together - especially play!
