Professionals

Canine Cognitive Dysfunction

Canine Cognitive Dysfunction

One Health

Canine Cognitive Dysfunction is often referred to as dog dementia due to its similarities with dementia and Alzheimer's disease in humans.

“Canine cognitive decline (CCD) is a major determinant of morbidity in older animals, with alterations in blood biomarkers, neuropathology, physiology, and behavior comparable to those seen in humans diagnosed with dementia and Alzheimer disease.”

Ehrenzweig J, Hunter RP. Canine cognitive decline and Alzheimer disease: clinical insights to solve a shared one-health problem. J Am Vet Med Assoc. 2023 Sep 27;261(11):1597-1604. doi: 10.2460/javma.23.02.0095. PMID: 37758186

Due to these similarities, researchers and scientists have used case studies relating to CCD as a model for their research into finding treatment for Alzheimer's disease in humans.

“Timely identification of CCD also opens opportunities for innovative interdisciplinary research that will contribute to a better understanding of the underlying mechanisms, early detection, and effective treatments for AD, ultimately benefiting human health as well.”

Ehrenzweig J, Hunter RP. Canine cognitive decline and Alzheimer disease: clinical insights to solve a shared one-health problem. J Am Vet Med Assoc. 2023 Sep 27;261(11):1597-1604. doi: 10.2460/javma.23.02.0095. PMID: 37758186

 

Finding a diagnosis

Between 14-22% of dogs older than eight suffer from age-related cognitive impairment (Salvin et al 2010), but diagnosing CCD can still be difficult. Traditional symptoms of CCD are often mistaken for normal signs of aging amongst most dog owners, leading to the condition often going undiagnosed. Since early diagnosis is vital in effectively slowing down the progression of CCD, establishing awareness amongst owners is crucial.

“Owners are our eyes and ears at home. Without their input, we'll miss the early signs of declining health or cognitive function, to be able to provide timely intervention to ensure optimum behavioral and physical health” – Dr Gary Landsberg, Veterinary Behaviorist and Scientific Advisor at SoluPet.

Diagnosing CCD is often done through a process of elimination. Many symptoms overlap with other common conditions in senior dogs. Therefore, veterinarians must rule out other medical causes before attributing them to cognitive decline – including pain (especially musculoskeletal and dental), loss of sense and systemic or local disease. This can be done by thoroughly evaluating the patient’s complete history and conducting a complete physical examination, including neurological and musculoskeletal evaluations.

Tracking symptoms is also an important step in coming to a correct diagnosis. Detecting early changes allows owners and veterinarians to establish a baseline comparison and track the disease’s progression. There are a few measures that can be taken by both parties to do so. Veterinarians should include:

  • Starting cognitive screenings around the age of 7 or 8 years of age, with more detailed assessments based on findings.

  • Using validated tools such as the DISHAA Scale, Canine Dementia Scale (CADES) questionnaire or Canine Cognitive Dysfunction Rating (CCDR) Scale to help track behavioral changes over time.

Owners can also track symptoms over a period of time using SoluPet’s Cognitive Symptom Tracker to aid their veterinarian in determining a diagnosis.

“Aging pets are at a higher risk for cognitive dysfunction and medical disease necessitating routine behavioral and physical screens and record keeping for early identification and treatment.”

Provoost L. Cognitive Changes Associated with Aging and Physical Disease in Dogs and Cats. Vet Clin North Am Small Anim Pract. 2024 Jan;54(1):101-119. doi: 10.1016/j.cvsm.2023.08.002. Epub 2023 Sep 16. PMID: 37722947.

Treatments and Management Strategies

Although there is no known cure for CCD, once an official diagnosis has been made there are a number of approaches that can be taken to help support the patient both medically and holistically.

Pharmaceutical options

When it comes to medications, there are few options on the market that treat CCD. Anipryl (selegiline) – a selective irreversible monoamine oxidase B inhibitor – is the only drug labeled for use for CCD. It has been shown to be effective for up to 70% of dogs being treated for CCD.

“Two classes of pharmaceuticals have shown clinical efficacy in reducing signs of CDS in dogs, monoamine oxidase inhibitors, and cholinergic drugs. Selegiline (also known as L-deprenyl or Anipryl), a monoamine oxidase inhibitor, is an FDA-approved treatment of CDS in dogs that has been shown to slow progression and increase life span by 6 months. Selegiline prevents the catabolism of dopamine, serotonin, epinephrine, and norepinephrine and is thought to have neuroprotective, antioxidant, and anti-inflammatory effects. However, response to selegiline varies, and in an early study, it proved effective in improving visuospatial working memory in aged dogs but failed to improve performance in young dogs. Interestingly, selegiline has been found to improve operant conditioning, as well as attention, in young dogs. These differing results may indicate an age effect on different cognitive domains, as well as a population effect. Treatment of pain and systemic disease to increase quality of life is warranted. Medications that may be useful for treating pain and sleep disruptions include gabapentin, amantadine, nonsteroidal anti-inflammatories, and benzodiazepines. Although both classes of medications may be helpful to ensure a restful night, paradoxical effects can be observed with either so trial before use is recommended. If selegiline is not used for cognitive health, due to contraindication, cost, poor response, or adverse reactions, SSRIs can be considered to treat fears and anxieties in senior cats and dogs. Care should be taken when using medications with anticholinergic side effects, such as TCAs.”

Provoost L. Cognitive Changes Associated with Aging and Physical Disease in Dogs and Cats. Vet Clin North Am Small Anim Pract. 2024 Jan;54(1):101-119. doi: 10.1016/j.cvsm.2023.08.002. Epub 2023 Sep 16. PMID: 37722947

Exercise the mind and body

Other ways to treat CCD that don’t include medication include mental enrichment and physical exercise. 

Exercise is a simple way to provide neuroprotection to a senior dog. Shorter, more frequent walks to encourage sniffing provide mental stimulation while also aiding their physical health. In cases where patients suffer from mobility issues, using the aid of a stroller or wagon to allow new sniffing opportunities is beneficial for a dog’s mental enrichment.

Pet parents can also aid mental stimulation in their homes. Simple additions such as puzzle toys, sniffing games, reteaching simple commands like sit/stay, and fetch with soft, safe chew toys can help to engage otherwise unexercised parts of their brain. 

It’s important to ensure that any exercise and enrichment activities meet the specific cognitive and mobility abilities of each individual pet. Try to avoid making things too difficult so that the outcome results in stimulation, not frustration. 

Adjusting your patient's environment

Similar to humans, senior dogs’ mobility declines. This, combined with the cognitive impacts caused by CCD, can make navigating their normal environment challenging. To help dogs living with CCD, there are a few measures that owners can take to make their pets more comfortable. Simple steps like ensuring their dog has designated areas to sleep and relax when they feel anxious, regulating their body temperature, eliminating slippery surfaces, and providing steps to help them access elevated areas can help reduce stress and boost their pet’s sense of confidence and security.

“Environmental changes at home may be helpful for any senior companion animal and should focus around meeting their functional needs. Companion
animals should have a comfortable space dedicated to them to sleep and
relax. As companion animals age, they lose their ability to thermoregulate efficiently, so it is important they can stay warm during cold times and keep cool when hot. They should be able to navigate their home with ease that will allow them to easily access resources such as food and places to eliminate. For instance, traction on slippery flooring (ie, carpets, runners) can reduce fear associated with slipping in companion animals affected with neurologic or musculoskeletal disease. Consider providing steps or low shelving to get to elevated surfaces more easily. There are commercial
products but at home, items may be just as useful, such as linen-filled suitcases or old sofa cushions strategically placed.”
Provoost L. Cognitive Changes Associated with Aging and Physical Disease in Dogs and Cats. Vet Clin North Am Small Anim Pract. 2024 Jan;54(1):101-119. doi: 10.1016/j.cvsm.2023.08.002. Epub 2023 Sep 16. PMID: 37722947.

The importance of nutrition

Diet can play a pivotal role in supporting a dog suffering from CCD. A lack of B vitamins and docosahexaenoic acid (DHA), chronic oxidative stress, inflammation, and reduced brain glucose metabolism can lead to mitochondrial dysfunction, decreased neuronal function and cognitive decline.

Studies have shown that dogs who are fed high-quality commercial diets designed for their age, size, or health were 2.8 times less likely to develop CCD than dogs fed low-quality commercial food or table scraps.

“The effectiveness of two interventions, dietary fortification with antioxidants and a program of behavioral enrichment, was assessed in a longitudinal study of cognitive aging in beagle dogs. A baseline protocol of cognitive testing was used to select four cognitively equivalent groups: control food-control experience (C-C), control food-enriched experience (C-E), antioxidant fortified food-control experience (A-C), and antioxidant fortified food-enriched experience(A-E). We also included two groups of young behaviorally enriched dogs, one receiving the control food and the other the fortified food. Discrimination learning and reversal was assessed after one year of treatment with a size discrimination task, and again after two years with a black/white discrimination task. The four aged groups were comparable at baseline. At one and two years, the aged combined treatment group showed more accurate learning than the other aged groups. Discrimination learning was significantly improved by behavioral enrichment. Reversal learning was improved by both behavioral enrichment and dietary fortification. By contrast, the fortified food had no effect on the young dogs. These results suggest that behavioral enrichment or dietary fortification with antioxidants over a long-duration can slow age-dependent cognitive decline, and that the two treatments together are more effective than either alone in older dogs.”

Milgram NW, Head E, Zicker SC, et al. Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study. Neurobiol Aging. 2005;26(1):77-90. doi:10.1016/j.neurobiolaging.2004.02.014


Future biomarkers

Establishing reliable and definitive biomarkers for CCD is a difficult but essential task in the fight against the disease. Researchers are constantly looking into various tests that could unlock new possibilities when it comes to diagnosing CCD.

Although more research is required before it can be widely applied, a biomarker that is promising is the plasma neurofilament light (NfL) protein level, which increases as dogs age. It is a non-specific biomarker of neuronal death, making its rate of change over time a possible indicator for CCD. In conjunction with the use of the CCD Rating scale, a recent study, which used an immunomagnetic reduction assay to detect the concentration of plasma NfL in dogs, found that dogs diagnosed with CCD demonstrated significantly higher NfL levels than dogs that have not been diagnosed. 

Another potential biomarker that is being investigated is Cerebrospinal fluid amyloid β (CSF Aβ42). Research shows that laboratory beagles with higher levels of CSF Aβ42 had lower performances in cognitive tasks, possibly indicating that cognitive impairment is likely to occur prior to cerebral amyloid deposits. 

 

*The information on this page is intended solely for use by veterinary professionals.  It is for informational purposes only and not a substitute for independent professional medical judgment, expertise, or clinical decision-making.  Veterinarians are responsible for evaluating the applicability of any information for their patients and exercising appropriate clinical judgment.  Nothing on this page constitutes medical advice, diagnosis, treatment, or an endorsement of any specific therapeutic approach.  If you are not a veterinary professional, you should not rely on this information and should discuss any questions about the information on this page with your Veterinary professional.

Helpful resources

2023 AAHA Senior Care Guidelines for Dogs and Cats:
https://www.aaha.org/resources/2023-aaha-senior-care-guidelines-for-dogs-and-cats/ 

 

Senior Dog Veterinary Society:
https://www.seniordogvets.com 

 

Canine Cognitive Dysfunction Rating Scale:
https://www.sciencedirect.com/science/article/abs/pii/S1090023310001644 

Canine Dementia Scale (CADES):
https://www.sciencedirect.com/science/article/abs/pii/S0168159115002373 

 

Senior Dog Enrichment:
https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information/senior-dog-enrichment

Read more