Cognitive Dysfunction Flashcards
1
Q
What is Cognitive Dysfunction?
A
- Cognitive functions include the mental processes of perception, awareness, learning, and memory, which allow an individual to acquire information about the environment and decide how to act
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Cognitive dysfunction syndrome (CDS) is a neurobehavioral disorder affecting geriatric dogs and cats that is characterized by an age-related decline in:
- Cognitive abilities sufficient to affecting functioning
- Behavior changes that are not attributable to other medical conditions
2
Q
What is the incidence of CDS in dogs?
A
- Prevalence is extremely high
- the older the dog the greater the prevalence
- 28% in 11-12 years old
- 68% in 15-16 years old
- Nearly 100% of dogs >16 displayed at least 1 sign
3
Q
Are there sex or breed correlations with CDS?
A
- No sex or size correlations
- No breed predilections
4
Q
Why is CDS under-reported?
A
- Short appointment times - contribute to the reason why clinical signs of CDS are often overlooked by both practitioners and owners
- Owners may not notice subtle signs or think it is necessary to discuss them, especially if they suspect that nothing can be done
-
Better education of both clients and veterinarians is needed to increase the diagnosis of CDS
- more dogs may then receive treatment
5
Q
What is Canine Cognitive dysfunction syndrome (CDS)?
A
- As dogs age, most body systems undergo physiologic and metabolic changes
- These changes can manifest as behavioral issues, with the most common being:
- Separation anxiety
- Destruction
- House soiling
- Each body system can undergo differing metabolic and physiologic abnormalities that also overlap with each other
6
Q
What is the appropriate Medical Evaluation for CDS?
A
-
Thorough physical examination
- Neurologic examination
- Orthopedic examination
- Pain assessment
-
Appropriate diagnostic testing
- CBC
- Biochemistry panel
- Urinalysis
- Systemic blood pressure
7
Q
What additional testing is may be needed depending on the clinical signs?
A
- Radiography
- Ultrasonography
- Endocrine tests
- Thyroid
- Cushing’s
- Magnetic resonance imaging and cerebral spinal fluid to assess for the presence of certain intracranial lesions/diseases that might mimic CDS
- Inflammatory
- Infectious
- Neoplastic
8
Q
What are some physical changes that could be mistaken for CDS?
A
- Arthritis in joints
- Spinal spondylosis
- Decreased muscle mass (sarcopenia)
- Nuclear sclerosis
- Cataracts
- Deafness
- Decreased smelling ability
- Decreased taste senses
- Changes in digestion and respiration
- Urinary incontinence
9
Q
What are the similarities of canine CDS and Alzheimer’s?
A
- Human patients often exhibit movement disorders, including restlessness, impaired gait, and tremors
- Concurrent behavioral and neurologic signs in aging canine patients have also been documented
- In a study of 21 dogs >7years
- Those with CDS were 2x as likely to show neurologic deficits as dogs without CDS
- Brains of Dogs with CDS have neuropathological lesions similar to those seen in people with dementia
10
Q
What are the symptoms of Canine Cognitive Dysfunction Syndrome?
A
- Decreased reaction to stimuli
- Decreased exploratory behavior
- Confusion
- Disorientation
- Cognitively impaired older dogs have higher locomotor activity and spend more time in aimless activity than young dogs (younger than 9 years)
- The more severe the cognitive impairment, the higher both of these measures
- Cognitively impaired older dogs have higher locomotor activity and spend more time in aimless activity than young dogs (younger than 9 years)
-
Decreased interaction with owners and other dogs
- Social responsiveness is primarily affected by age but is also influenced by severity of cognitive impairment
- Young dogs
- Engage in more physical contact with humans
- Have more vocalizations in response to social isolation
- Aged dogs spent more time near a mirror
- suggests deficit in habituation to the reflection of a dog image
- Irritability
- Slowness in obeying commands
- Decreased responsiveness to sensory input
- Problems performing previously learned behaviors
- Altered sleep-wake cycles
- Radiotelemetry monitoring in elderly dogs
- Sleep-wake patterns were dramatically altered
- Increase in the total amount of time spent in slow-wave sleep during the daytime
- Increase in the time spent awake during the night
- Sleep-wake patterns were dramatically altered
- Radiotelemetry monitoring in elderly dogs
11
Q
What pathogenic changes are believed to contribute to CDS?
A
- Decreased in gray and white matter
- Reduction in number of neurons
- Generalized gliosis
- Degeneration of white matter
- Demyelination
- Neuroaxonal degeneration
- Increases in ventricular size
- Meningeal fibrosis and calcification
- Presence of B-amyloid (AB) plaques
12
Q
What are Amyloid Plaques?
A
- Deposition of amyloid plaques in the brain parenchyma an the walls of the cerebral blood vessels can play a role
- AB is a protein produced by the degradation of amyloid precursor protein
- The prefrontal cortex is the first area affected, followed by the temporal cortex, the hippocampus, and the occipital cortex
- Regardless of position, the amount and extent of AB deposits correlate with the severity of cognitive impairment
13
Q
What affects brain health and vitality?
A
- Free radicals - problematic because of the high lipid content of the brain
-
Decreased glucose metabolism
- executive function and learning are affected
-
Reduced perfusion of brain tissue due to perivascular changes
- brain consumes 20% of the body’s total oxygen
14
Q
How does oxidative stress affect the brain?
A
- The brain’s high percentage of polyunsaturated fatty acids and lower levels of endogenous antioxidant activity make it very susceptible to oxidative damage
- Cellular metabolic processes release reactive oxygen species
- Oxidative damage to proteins, lipids, DNA, and RNA
- Results in neuronal death
- Normal activity of endogenous antioxidants balances the production of toxic free radicals
- Protective mechanisms begin to fail with age
- Oxidative damage ⇢ cognitive decline in dogs
- An increase in oxidative end products in the brain of aged dogs correlates with more severe behavioral changes
15
Q
What nervous system functional changes are seen in CDS?
A
-
Neurotransmitter function changes as chemical levels are altered
-
Depletion of catecholamine neurotransmitters
- Monoamine oxidase
- Serotonin
- Dopamine
- Decline in the cholinergic system
- Acetylcholine
- Increase in monoamine oxidase B (MAO-B) activity
- Reduction of endogenous antioxidants
-
Depletion of catecholamine neurotransmitters
16
Q
How is CDS diagnosed?
A
- Diagnosis of exclusion
- Although CDS is a diagnosis of exclusion, the presence of any of these signs as a new behavior in middle-aged dogs should create suspicion of CDS
- Any 2 of these signs should raise a very high index of suspicion (DISHAA)
-
Owners may be slower to perceive
- Reduced interaction with their dog
-
Confusion on the part of their dog
- These are not as obvious as noting whether the dog paces all night or abandons established house-training
17
Q
What is DISHAA?
A
- D - Disorientation
- I - Altered interactions
- S - Sleep-wake cycle disturbances
- H - Problems with house-training
- A - Activity
- A - Anxiety
18
Q
Why is a Physical exam and medical workup essential?
A
- May have underlying, treatable metabolic issues
- These may be chronic and continue to contribute to the behavior issues, even if treated
- Treat behavior issues after any medical issues have been addressed and treated
