Advancements in Assessment and Management of Canine Cognitive Dysfunction
Canine cognitive dysfunction (CCD) is a progressive, neurodegenerative disease in which there is a decline in cognitive function. Functional tasks such as learning, memory, perception, and awareness are affected . Despite its detrimental effects on the quality of life of senior dogs, there is hope that with the development of early detection tests and nutritional and nutraceutical supplementation, a preventative approach to managing this disease can be taken.
CCD may not be a well-known condition amongst pet owners. Perhaps the colloquial term of “doggy Alzheimer’s” might sound more familiar. Despite the differences in terminology, there are pathophysiologic and symptomatic commonalities between the canine and human versions of this condition .
Regardless of the pet owner’s knowledge of the correct vocabulary, the symptoms of CCD are being recognized by the owners of aged pets. House-soiling, disorientation, and changes in sleep-wake cycles are common observations. Unfortunately, these symptoms are rarely noticed until the pet is of at least 11 years or older, at which point significant loss of cognitive function has occurred . The exact cause of CCD is not known; however, individuals with CCD do possess various shared characteristics including brain lesions of beta-amyloid protein deposits, increased oxidative stress, and a reduction in neurons .
Araujo, et al., (2008), found that symptoms were detected much earlier when cognitive function was tested in a laboratory setting. Neuropsychological tests designed to assess short-term working memory indicated deficits in this capacity in dogs as early as 6 years of age. For these reasons, there is a need to detect and treat CCD early to minimize age-related impairment. Detection methods used in research are designed to assess several aspects of cognitive capacity and function. Examples include the assessment of complex learning ability in the Oddity Discrimination Task and testing of spatial memory using the Delayed Non-Matching to Sample (DNMP) Test .
Therapies for CCD including nutritional management and nutraceutical supplementation have shown promising results. A multimodal approach seems to provide the maximum benefits and should be considered when managing CCD . A number of strategic nutritional enhancements to the animal’s diet can be implemented fairly easily. Due to its high lipid content and limited ability for repair, the brain is highly susceptible to oxidative damage. Antioxidants, such as Vitamin E and C can reduce this oxidative cellular damage by scavenging free radicals. Other beneficial antioxidants include flavonoids and carotenoids from fruit and vegetable sources. During a 2005 study by Landsberg, G., dogs supplemented with antioxidants were found to have had improvement in performance in cognitive tasks as early as 2 to 8 weeks into the testing period . Long-chain polyunsaturated fatty acids (PUFA) are known for their anti-inflammatory properties. Fish oil provides two important PUFAs which are Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), commonly known as omega-3s . DHA is required for normal brain function and, a decrease in DHA levels in aged animals may contribute to a decline in cognitive function. Preliminary studies are showing that DHA can improve memory in dogs, and as a result, contribute to an improved overall quality of life . The dietary addition of medium chain triglycerides (MCT) increases ketone levels in the brain, which are used as an alternative energy source. This action reduces the amount of oxidation occurring that can damage cellular membranes as well as spares DHA from oxidative damage . There is a complementary benefit to providing a blend of PUFA and MCT as part of an animal’s dietary fat intake .
Several nutraceuticals have been identified as having beneficial effects for improving and delaying the onset of CCD. Gingko biloba can improve memory loss and reduce fatigue and anxiety in the elderly and slows the progression of Alzheimer’s in humans . Gingko biloba also stimulates several neurotransmitters and has antioxidant effects. Pyridoxine (Vitamin B6) and phosphatidylserine are important for the synthesis of several neurotransmitters and can inhibit age-related loss of receptors in the brain, respectively . Araujo, et al., (2008) found that dogs that were given a nutraceutical supplement containing Gingko biloba, phosphatidylserine, vitamin E and pyridoxine showed improved short-term memory when tested with the DNMP technique.
There is still much left that is unknown about CCD, but by understanding the pathophysiology of the dysfunction, we can begin preventative treatment early. With the addition of nutrition supplements and nutraceuticals to an animal’s preventative health care regiment, it is possible to delay the onset of symptoms. This preemptive approach not only addresses CCD but contributes to an overall good quality of life for dogs well into their senior years.
Brianne Bellwood, RVT, VTS (Clinical Pathology), CCRVN
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