MCI & SCD Flashcards
Describe the continuum of cognitive decline
Cognitively normal aging -> Subjective Cognitive Decline (SCD) (perceived decline without objective evidence) -> Mild Cognitive Impairment (MCI) (objective decline, no impact on daily function) -> Dementia (objective decline impacting daily function). Progression is not necessarily linear .
Normal Aging
Cognitively healthy older adults experience some declines in cognitive functioning
- Working memory
- Reasoning
- Episodic memory
- Processing speed
What is Mild Cognitive Impairment (MCI)?
Cognitive decline beyond what is expected in normal aging, noticeable by the person and others, but does not impair daily functioning. May or may not progress to dementia
What are some risk factors for MCI?
Lower education, APOE ε4 status, increased age, family history of Alzheimer’s or another dementia, conditions associated with cardiovascular disease
What are some common cognitive issues in MCI?
Forget things more often, miss appointments, lost train of thought, trouble following books/movies/conversations, difficulty making decisions/finishing tasks/following instructions, trouble finding way around familiar places, poor judgment
How is MCI misdiagnosed?
Sometimes MCI can be treated because it’s associated with some underlying condition
- Depression
- Metabolic causes
- Infectious causes
- Sleep disorders
- Neurological disorders
- Perceived stress
MCI Subtypes
- Cognitive tests will determine which subtype of MCI a person has
- Single domain = one cognitive domain impaired
- Multiple domain = multiple cognitive domains impaired
Brain Changes in MCI
- Atrophy: typically see people with MCI having less brain volume compared to Cognitively normal (CN)
- Amyloid buildup: Increases in amyloid deposits throughout the brain
- Tau buildup: Increases in tau, particularly in temporal lobe structures
**brain changes observed in MCI are reflective
of that for whatever dementia they are going to progress to. In the example provided that would be for someone with MCI who is likely to progress to AD because they have amyloid & tau. MCI can be a transition stage therefore if they are going to convert they will show dementia related brain pathology
MCI to Dementia
- 10-15% of individuals with MCI develop dementia each year
- 1/3rd of people with MCI due to AD develop dementia within 5 years
Factors that increase risk of development from MCI to Dementia:
- Older age
- APOE ε4 status
- Hippocampal atrophy on structural MRI
- Vascular abnormalities
- Biomarker positivity
- Tau
- Amyloid
Reducing progression from MCI to Dementia
- Treat underlying conditions
- Stopping medications that may be causing cognitive decline
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
What is Subjective Cognitive Decline (SCD)?
A self-perceived decline in memory and/or other cognitive abilities relative to a previous level, with an absence of objective neuropsychological deficits. May increase the likelihood of biomarker abnormalities and risk for future cognitive decline.
How is SCD Assessed?
*There is no standard method, it is self-report.
How is this problematic, examples?
- Bias: Mood (e.g., anxiety, depression) can distort perception.
- Lack of Insight: Some may not recognize their own decline.
- Vague Language: Terms like “memory problems” are subjective.
SCD outcomes
- At an individual level they do not exhibit more cognitive decline (by definition there are no objective declines in cognition), but at a group level they do show lower performance at baseline and more
decline over time. - Those who continuously report SCD are more likely to decline than those who are inconsistent
- Those who are concerned about their SCD decline more than those who are not concerned
Brain Changes in SCD
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 hippocampi
*If someone is going to progress they are more likely to have brain changes related to dementia
Conversion from SCD to MCI/Dementia
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 domain of cognition
➢ Onset of SCD within the last 5 years
➢ Age at onset of SCD ≥ 60 years
➢ Concerns 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)
SCD additional factors
Race, education, sex all influence SCD
