• Canine cognitive dysfunction

Simon Bertram
RCVS recognised Specialist in Veterinary Neurology
EBVS® European Specialist in Veterinary Neurology

What is canine cognitive dysfunction (CCD)?

CCD is also referred to as ‘canine dementia’ and is a neurobehavioural syndrome identified in older dogs (generally those >8 years). It shares similarities with human Alzheimer’s with deposition of amyloid plaques and cerebral amyloid angiopathy throughout the brain. The prevalence increases with age with 28% of dogs aged 11-12 years showing clinical signs, and up to 68% of dogs aged 15-16 years showing clinical signs. The condition is poorly recognised by owners and vets with only 2% of potential cases being diagnosed. It's a progressive condition and cannot be cured, but management strategies like medication, dietary supplements, and environmental enrichment can help alleviate symptoms and improve quality of life for affected dogs.

What are the main risk factors?

The major risk factor for CCD is age. However other risk factors identified include genetics, nutrition (dogs fed a low grade commercial diet or non-commercial diets were at higher risk of developing CCD), training history and concurrent diseases (particularly idiopathic epilepsy but there also is a possible association with hypothyroidism and hypertension).

What are the main clinical signs?

The main clinical signs associated with CCD include:

  1. Disorientation: Confusion or getting lost in familiar surroundings.
  2. Changes in sleep patterns: Increased restlessness at night or sleeping more during the day.
  3. Decreased activity levels: Reduced interest in playing or going for walks.
  4. Loss of house training: Accidents indoors despite previous house training.
  5. Alterations in social interactions: Changes in how the dog interacts with family members or other pets.
  6. Anxiety or agitation: Restlessness, pacing, or vocalizing for no apparent reason.
  7. Decreased responsiveness: Slower response to commands or cues.
  8. Changes in appetite or drinking habits: Increased or decreased appetite and/or thirst.
  9. Repetitive behaviours: Engaging in repetitive actions like pacing or licking.
  10. Loss of learned behaviours: Forgetting previously learned commands or tricks.

How is CCD diagnosed?

Canine cognitive dysfunction (CCD) is typically diagnosed through a combination of clinical signs reported by the owner, physical examination by a neurologist to rule out other medical conditions with similar symptoms, and sometimes specific cognitive function tests. There isn't a definitive diagnostic test for CCD, so diagnosis often involves ruling out other possible causes of the observed symptoms. Blood tests, urine tests, and imaging studies may be conducted to rule out underlying medical conditions. Sometimes MRI will be performed to rule out other conditions of the brain (esp. brain tumours) and look for changes typical for CCD (see below).

If other conditions are ruled out and the clinical signs are consistent with CCD, a diagnosis may be made based on the dog's age and symptom presentation.

Cognitive function tests:

CCDR, CADES, and DISHAA are all acronyms related to tools or methods used in the assessment or diagnosis of cognitive dysfunction in dogs:

  1. CCDR: Canine Cognitive Dysfunction Rating (CCDR) is a rating scale used by veterinarians to assess the severity of cognitive dysfunction in dogs. It evaluates various aspects of the dog's behaviour and cognitive function to determine the level of impairment.
  2. CADES: Canine Dementia Scale (CADES) is another rating scale used to assess cognitive dysfunction in dogs. Similar to CCDR, CADES evaluates different aspects of the dog's behaviour and cognitive abilities to gauge the severity of cognitive impairment.
  3. DISHAA: DISHAA stands for Dog Impairment in Spontaneous Home Activities Assessment. It is a method developed to assess cognitive dysfunction in dogs based on their spontaneous activities at home. This method involves observing the dog's behaviour and interactions in its natural environment to detect signs of cognitive decline.

Typical findings on MRI

Typical findings on MRI (Magnetic Resonance Imaging) related to canine cognitive dysfunction (CCD) are not always specific, but they may show changes consistent with brain atrophy and other age-related changes. These changes can include:

  1. Cerebral Atrophy: Shrinkage of the brain tissue, particularly in regions associated with memory and cognition.
  2. Ventricular Enlargement: Expansion of the fluid-filled spaces within the brain (ventricles), which can occur due to brain tissue loss.
  3. White Matter Lesions: Abnormalities in specific areas of the white matter of the brain, which is called Leukoariosis
  4. Microbleeds: very small areas of old and new bleed in the brain has been shown to be associated with CCD
  5. Size of the interthalamic adhesion: this is an area of the midbrain where the left and the right side of the brain meet. It has been shown that a reduction if the size of this structure is associated with CCD.

These findings on MRI can provide supportive evidence for a diagnosis of cognitive dysfunction in dogs, especially when correlated with clinical signs. However, it's important to note that these changes are not unique to CCD and can also be seen in other neurological conditions or as part of the normal aging process.

brain scans 2

Is there any treatment?

The treatment and management of canine cognitive dysfunction (CCD) typically involve a combination of strategies aimed at slowing the progression of cognitive decline and improving the quality of life for affected dogs. Some common approaches include:

  • Nutrition: Hills B/D is high in anti-oxidants and reported to improve brain function
  • Medium chain triglycerides (MCT) oils: provide an alternative energy source for the brain
  • Supplements: Phospatidylserine + S-Adenosyl-L-methionine (SAMe)
  • Environmental enrichment: regular exercise, social interactions and introduction of new toys and games has been shown to prevent or delay cognitive decline in older dogs
  • Regular Exercise: Physical activity is important for maintaining overall health and cognitive function in dogs. Regular walks, playtime, and other forms of exercise can help reduce anxiety, improve mood, and promote mental stimulation.
  • Routine and Structure: Establishing a predictable daily routine and environment can help reduce confusion and anxiety in dogs with CCD.
  • Behavioural Therapy: Working with a veterinary behaviourist to address specific behavioural issues associated with CCD, such as house soiling or night-time restlessness, can be helpful.
  • Anti-anxiety medications: gabapentin/pregabalin, fluoxetine, benzodiazepines
  • Selegiline: thought to exert beneficial effects by restoring dopaminergic balance some benefit has been shown in clinical trials but this will vary markedly according to the individual dog and the duration of use
  • Other complementary therapies: with the primary goal of reducing anxiety and normalising the sleep/wake cycle include melatonin, acupuncture, pheromones (DAP), lavender essential oils, valerian root. There is no evidence to support the use of these therapies.

While there is no cure for CCD, these management strategies can help slow the progression of the disease and improve the dog's quality of life. It's essential for owners to work closely with their veterinarian to develop a comprehensive treatment plan tailored to the individual needs of their dog.

Top Tips:

  • The diagnosis is based on specific clinical signs and the combination of any other intracranial structural disease
  • Owner questionnaires like DISHAA, CCDR and CADES are very useful
  • “Typical” MRI changes are not always present
  • Despite there not being any treatment different management strategies can help to improve or slow down the deterioration of Quality of life

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