12 - MCI and SCD

Question 1

What is it called when people feel like there is problems with their function, but they do not experience objective evidence of decline on cognitive tests?

Answer 1

Subjective cognitive decline

Question 2

What is it called when people experience cognitive decline beyond what is expected for normal aging, but it does not impair their daily functioning?

Answer 2

Mild cognitive impairment

Question 3

True or false: Some decline can continue to progress to the point they impair daily functioning.

Answer 3

True: This leads to dementia

Question 4

What are the 6 stages of impairment through aging.

Answer 4

Stage 1: No objective or subjective evidence for cognitive decline or impairment + no behavioural symptoms
Stage 2: Subjective or subtle objective cognitive decline (or both) , and not meeting criteria for impairment, mild, recent onset behavioural symptoms could co-occur
Stage 3: Objective cognitive decline to the level of impairment, and mild functional impairment possible, but independence perserved
Stage 4: Mild dementia
Stage 5: Moderate dementia
Stage 6: Severe dementia

Question 5

True or false: The progress through the stages of cognitive decline are linear.

Answer 5

False: It is not necessarily linear
→ may even improve or remain stable without progressing to dementia

Question 6

True or false: There is no gurantee of progression to dementia.

Answer 6

True: some people can move from stage 1 to stage 4 for example
→ p.ex: we see this in vascular dementia which can result from acute events like a stroke, which expedites cognitive decline and impairs cognitive function to stage 4, rather than passing through progressive phases (stage 2 and 3)
→ you don’t have to pass through every stage, although some do

Question 7

__ - __% convert from MCI to dementia.

Answer 7

10 - 15%

Question 8

Cognitively healthy older adults experience some declines in cognitive functioning over time BUT these declines do not impair daily functioning; this includes declines in… (4)

Answer 8

→ Working memory
→ Reasoning
→ Episodic memory
→ Processing speed

Question 9

What is pre-clinical dementia?

Answer 9

• Otherwise known as SCD
• Silent phase: brain changes without measurable symptoms
• Individual may notice changes, but not detectable on tests
• “A stage where the patient knows, but the doctor doesn’t”
  → brain changes without measurable symptoms, individuals are typically first to notice (dr. doesn’t know but patient knows)

Question 10

Explain what happens in the process from general aging to MCI.

Answer 10

• Declines that are more severe then what is expected for their age and education is considered mild cognitive impairment
  → show objective results of cognitive impairment
  → 1.5 standard deviation below when compared to people at the same age and education, in at least one cognitive domain
  → start to score objectively lower and we can see a significant difference
  → Changes in memory
  → Changes in language
  → Changes in visuospatial function
  → Changes in attention or executive functioning

Question 11

What are changes seen from general aging to MCI?

Answer 11

• Cognitive changes are of concern to individual and/or family
• One or more cognitive domains impaired significantly
• Preserved activities of daily living

Question 12

Once the declines begin to impair ___ ___, the individual is diagnosed as having dementia.

Answer 12

Daily functioning

Question 13

What is MCI?

Answer 13

• A condition in which someone experiences cognitive declines beyond what is expected in normal aging
• These declines are severe enough to be noticed by the person (and family members/friends)
• The declines do not affect their ability to carry out everyday activities
• May (or may not) progress to develop dementia
  → those with MCI are at a greater risk of developing though

Question 14

What are risk factors of MCI?

Answer 14

• Lower education
• APOE ε4 status
  → we all have APOE 1, 2 and 3, but 4 shows that we can potentially develop alzheimers
• Increased age
• Family history of Alzheimer’s or another dementia
• Conditions associated with cardiovascular disease
• addressing some of the modifiable risk factors can help you revert back

Question 15

What is the trouble with diagnosing MCI?

Answer 15

• Misdiagnosis often happens because we focus on one specific symptom
  → p.ex: telling your doctor you’re having sleep issues, they’ll only focus on that one instead of other cognitive decline issues
• Often misdiagnosed because it’s associated with some underlying condition, such as:
• Depression
  → just by treating depression, we can revert back to stage 1
  → but untreated, it can continue to progress to dementia
  → depression is often a key underlying condition
• Metabolic causes
• Infectious causes
  → UTI can also cause impairment at a later age, but these are treatable so can help revert back to stage 1
• Sleep disorders
  → can cause daytime fatigue and MCI and cognitive decline
  → just addressing your sleep disorder can help move away from MCI or further decline
• Neurological disorders
• Perceived stress
  → can lead people with MCI to develop dementia

Question 16

What are cognitive problems seen in MCI?

Answer 16

• changes in memory
• changes in language
• changes in visuospatial function
• changes in attention/executive function
• typical cutoff is 1.5 standard deviations below age- and education-matched means
  → we wanna be 24+, anything lower is worrisome

Question 17

What does the MoCa do for MCI?

Answer 17

• Designed to detect MCI
• scored out of 30; <26 = diagnosis of MCI/dementia
• sample questions:
  → name pictures of animals
  → remember 5 words
  → providing the date and location

Question 18

What are common cognitive issues seen in MCI?

Answer 18

→ You forget things more often
→ You miss appointments or social events
→ You lose your train of thought
→ You can’t follow the plot of a book or movie
→ You have trouble following a conversation
→ You find it hard to make decisions, finish a task or follow instructions
→ You start to have trouble finding your way around places you know well
→ You begin to have poor judgment
→ Your family and friends notice any of these changes

Question 19

True or false: Cognitive tests can determine which subtype of MCI a person has.

Answer 19

True

Question 20

Explain the different trajectories to MCI subtypes.

Answer 20

Amnestic MCI: Memory is mainly affected
- Single-domain MCI: memory only
–> Risk of Alzheimers
- Multi-domain MCI: memory + other domains
–> Risk of Alzheimers and vascular Alzheimers
Non-amnestic MCI: Other cognitive functions are affected
- Single-domain MCI: one domain
–> Risk of other dementia (frontotemporal dementia; lewy body dementia; parkinson’s disease dementia)
- Multi-domain MCI: Several domains
–> Risk of other dementia (frontotemporal dementia; lewy body dementia; parkinson’s disease dementia)

Question 21

What are the brain changes in MCI?

Answer 21

• Atrophy: typically see people with MCI having less brain volume compared to CN – neurodegeneration (loss of volume in grey matter)
• Amyloid buildup: increases in amyloid deposits throughout the brain
  → more amyloid in the brain, you see more yellow and red
  → this is retention of the amyloid binding tracer
  → amnestic MCI: intermediate amount of tracer retention
  → alzheimers: large amount of tracer retention
• Tau buildup: increases in tau, particularly in temporal lobe structures
  → presented in amnestic and non-amnestic subtypes

Question 22

What are some statistics about MCI to dementia progression?

Answer 22

→ 10-15% of individuals with MCI develop dementia each year
→ 1/3rd of people with MCI develop dementia within 5 years

Question 23

What are some factors that increase risk of development from MCI to dementia?

Answer 23

• Older age
• APOE ε4 status
• Hippocampal atrophy on structural MRI
• Vascular abnormalities
• Biomarker positivity
  → Tau
  → Amyloid

Question 24

How can we reduce progression from MCI to dementia?

Answer 24

• Treat underlying conditions
• Stopping medications that may be causing cognitive decline
  → benzos are used often for other conditions which can influence other problems
• Non-pharmalogic interventions include:
  → Regular physical exercise
  → A diet in low fat and rich in fruits and vegetables
  → Omega-3 fatty acids
  → Keeping your brain active
  → Being social

Question 25

What is SCD?

Answer 25

• Individuals may succumb to and perceive subtle declines in their cognitive abilities, even though cognitive test performances remain the same
  → refers to the self-perception of cognitive decline and does not require confirmation by external sources (friends, family, doctor, etc.)
  → early indicator of compensation
  → Perceived deficits in cognition
  → No objective deficits in cognition (absence of objective change in cognitive tests)
  → overlaps with the normal aging phase

Question 26

SCD occurs when an older adult presents with…

Answer 26

→ A self-perceived decline in memory and/or other cognitive abilities relative to the previous level of performance,
→ An absence of objective neuropsychological deficits

Question 27

SCD increases the likelihood of having biomarker abnormalities consistent with ___ pathology - may show an increase amyloid and tau buildup associated with ___

Answer 27

Dementia; AD
→ but because there’s no objective way to test this, doctors won’t typically send them to get an MRI done – if they did, they would see this buildup

Question 28

SCD increases risk for…

Answer 28

future pathological cognitive decline and dementia

Question 29

How can we look at SCD?

Answer 29

• The cognitive change index questionnaire
  → questions in a very subjective way
• Examples of questions:
  → About how often do you have trouble remembering things? 1 = Very often; 2 = often; 3 = Sometimes; 4 = Rarely; 5 = Never
  → Compared to 10 years ago, would you say that your memory is: 1 = much worse; 2 = a little worse; 3 = the same; 4 = a little better; 5 = or much better
  → first 12 questions of the Cognitive change index focus on memory (organization, planning, attention, etc.)
• There’s no common threshold to determine whether someone has SCD or not
  → no standardized test, researchers use different questionnaires

Question 30

What does a study say about the correlation between subjective and objective cognitive performance?

Answer 30

→ as you progress closer to a clinical diagnosis over months, it switches from self to informant reports, as informant reports become more correlated with cognition than the reported self
→ if a healthy older adult makes memory complains, and over time the person that’s closest to them starts to say the same thing, you can be more confident that this person is on the SCD trajectory, which allows double confirmation

Question 31

Are there differences in baseline cognition between those with and without SCD?

Answer 31

• Baseline cognition between those with and without SCD differs in some domains and not all
• there are some differences, but they aren’t very specific - even with liberal stats there are no differences in working memory and visuospatial ability, only in the first 4
  → SCD differs in some domains but not all

Question 32

Are there differences in cognition between those with and without SCD in the long-term?

Answer 32

• Visuospatial ability and working memory, are significantly different in longitudinal sets (even though at baseline showed virtually no differences)
  → this shows a steeper decline in cognitive function over time

Question 33

Those who repeatedly and continuously report SCD are more likely to…

Answer 33

• Those who repeatedly report SCD are more likely to decline to dementia
• Those who continuously report SCD are more likely to decline than those who are inconsistent
  → declines are much steeper over time for those who consistently report SCD
• those who report consistently: 4x at risk of developing AD compared to individuals without SCD, and 2.5x compared to those with inconsistent SCD, and still double to those who had SCD but were not worried
  → but still, the only consistent method at this stage is MRI or PET scans

Question 34

Those who are concerned about their SCD…

Answer 34

decline more than those who are not concerned

Question 35

What are brain changes in SCD?

Answer 35

• Atrophy: typically see people with SCD have less brain volume compared to non-SCD older adults
  → Increase complaints = more decline in the left and right hippocampus (reduced grey matter)
  → this indicates that if a person were to do a working memory test or verbal memory test, they may have lower scores but it won’t show at the time, it would be over time
• MCI and SCD groups showed a similar pattern of reduced grey matter density in the medial temporal, frontal, and other regional distributed brain regions
• Amyloid buildup: Increases in amyloid deposits throughout the brain
• Tau buildup: Increases in tau, particularly in the entorhinal region
  → SCD has a moderate association with tao buildup

Question 36

What are the features that increase likelihood of preclinical AD for those who report SCD?

Answer 36

• Twice as likely to develop dementia than those without SCD
• Features that increase likelihood of preclinical AD (SCD Plus)
  → Subjective decline in memory rather than in other domains of cognition
  → Onset of SCD within the last 5 years
  → Age at onset of SCD ≥ 60 years
  → Concerns (worries) associated with SCD
  → Feeling of performing worse than others of the same age group
  → Confirmation of cognitive decline by an informant
  → Presence of the APOE ε4 genotype
  → Biomarker evidence for AD (defines preclinical AD)
  → other risk factors similar to AD (lifestyle; smoking, physical activity, etc.)

Question 37

What are the factors that play a role in the conversion from SCD to deeper decline? (3)

Answer 37

Higher education:
- Higher education in SCD = greater risk of conversion to dementia
- Those with higher education may be more sensitive to declines in their cognitive functioning than lower educated individuals
→ more likely able to subjectively detect the change (much more self-aware to this change)
- Think of cognitive reserve…. Higher educated individuals require more pathology for a decline
→ may be able to compensate for a longer period of time and may appear clinically normal (which later shows greater amount of amyloid buildup)
Sex differences:
- There are more females diagnosed with dementia than males
- Females exhibit more pathology than males
- Females also show more decline in cognition associated with the same amount of brain changes as males
- Females are more likely to have a faster progression than males
Race differences:
- Black older adults are twice as likely to develop dementia than White older adults
- Racial differences exist in prevalence of risk factors (cardiovascular health p.ex)
- Some studies suggest Black older adults have a faster progression and shorter survival time after diagnosis than White older adults