Can dogs become senile?
Dogs are living longer than ever and that means they have a chance to develop diseases associated with advanced age. Cognitive dysfunction syndrome (CDS) is the name assigned to a set of symptoms associated with behavior changes that may include:
- Waking at night/disrupted sleep cycles
- House soiling
- Escalating separation anxiety
- Disorientation
- Excessive vocalization
- Increased irritability
- Phobias or new fears
Dogs showing one or more of these signs could have a loss of memory or learned behaviors, perception deficits, or a loss of spatial awareness.
It is important to identify the patterns of behavior that are consistent with CDS to provide appropriate early intervention that may improve the quality and length of life. Currently, age, gender, and neuter status are recognized as risk factors for CDS. Dogs at greater risk of developing CDS are those older than 10 years, females more than males, and neutered more than intact dogs.
What happens in the brain when a dog develops CDS?
The brain is separated from the circulation by the “blood-brain barrier”, which regulates the delivery of nutrients from the bloodstream to all the cells of the brain. As dogs get older, the blood-brain barrier becomes more permeable (or “leaky”), allowing some potentially harmful molecules access to brain tissue, which can contribute to a decline in cognitive function.
Normal metabolism in all organs leads to oxidative damage and the production of free radicals – unstable molecules that can damage proteins, cellular fats, and molecules responsible for cellular health and reproduction. In the brain, damage from free radicals can lead to nerve cell dysfunction and death. Another factor in the development of CDS is that the brain shrinks and the tissue is replaced by cerebrospinal fluid (CSF), which causes brain swelling.
Is there any way to slow or reverse the process of oxidative damage to the brain?
Antioxidants are molecules that decrease the number of oxidants and free radicals in the body's tissues. Several antioxidants are found in food, including:
- Vitamin E
- Vitamin C
- Selenium
- L-carnitine
- Alpha-lipoic acid
- Flavonoids
- Carotenoids
Research shows that feeding a diet with high levels of antioxidants can slow the rate of cognitive decline in some older dogs by decreasing the production of free radicals and increasing the body’s ability to clear free radicals. The studies showed significant improvement in learning and memory of learned tasks in old dogs fed an antioxidant-fortified food. However, there were no beneficial effects in learning or memory in young dogs. It was conjectured that young dogs had not yet developed oxidative damage at a level impacted by increased antioxidants in the diet.
What can I feed my dog to preserve his mental capacity?
Before nutrition can be of any benefit to cognitive function, CDS must be confirmed as the appropriate diagnosis. Many diseases can cause symptoms similar to CDS. For instance, chronic pain is quite distracting and can cause a dog to behave very differently from the way they behave when not experiencing pain or discomfort. If pain or a systemic disease is present, it is important to resolve or treat those medical issues first.
Once CDS is confirmed, work with your veterinarian to examine your dog's current food and compare levels of the key nutritional factors that support cognitive function. There are veterinary therapeutic diets in the marketplace specifically designed to help support brain health (e.g., learning and memory of learned tasks).
Research also shows that dogs with CDS may benefit from environmental enrichment, such as increased activity through regular exercise, interactive toys, and regular interaction with other dogs. The combination of nutrition and environmental enrichment was more effective than nutrition alone.
Improvements in the abnormal behaviors associated with CDS are typically seen within 6–12 weeks after starting to feed a diet containing high enough levels of antioxidants. If no improvements are seen within 12 weeks, it is unlikely that nutrition alone will make a difference. Dogs who don’t respond will need additional follow-up and investigation by their family veterinarian. Medications and supplements can be discussed with your veterinarian in conjunction with diet therapy.
