Aging, MCI, dementia Flashcards
What happens with normal brain aging?
brain volume shrinks; dopamine and serotonin levels decline; cerebral blood flow decreases; accumulation of ischemic white matter lesions; mild AD pathology
Which brain functions decline with age?
working memory, STM, LTM, speed of processing, but not verbal knowledge or wisdom
Mild cognitive impairment
mild cognitive difficulties in excess of normal aging with preserved activities of daily living
Prevalence of MCI
12-18% of people over age 60 globally
Conversion rate of MCI to dementia
5-6% per year
5 predictors of conversion of MCI to dementia
older age, high medical burden, APOE ε4 status (more copies of allele = higher risk), low education, low participation in leisure activities
2 main types of MCI
amnestic (memory mainly affected) and non-amnestic (other cognitive functions affected)
2 subtypes of amnestic and non-amnestic MCI
single domain and multi-domain
Single domain amnestic MCI
only memory is affected; risk of AD
Multi-domain amnestic MCI
memory and other domains are affected; risk of AD/VaD or vascular dementia
Disease risks of single and multi-domain non-amnestic MCI
other dementias (e.g. FTD, DLB, PDD)
Dementia
impairment of multiple cognitive functions and activities of daily living; an insidious decline from normal functioning
Onset and course of dementia
onset in middle to late adulthood with a progressive course
Which gender has higher risk of dementia?
females, because they live longer
When does dementia prevalence begin to exponentially increase?
ages 70-79
Modifiable risk factors of dementia in early and middle ages
less education and health problems (e.g. hearing loss, hypertension)
Modifiable risk factors of dementia in later life (above 65)
health problems (e.g. smoking, depression, physical inactivity)
5 ways to diagnose dementia
history of progression; neuropsychological confirmation; interview with collateral regarding ADL; MRI (regional atrophy); blood biomarkers and neuroimaging techniques specific for each type
Prevalence of AD
7% of people over age 65
Incidence of AD
14 per 1000 people over age 65
Who is AD more common in?
females and APOE ε4 allele carriers
Clinical presentation of AD in early stages
mild episodic memory deficit
Clinical presentation of AD in middle stages
moderate-severe episodic memory deficit; semantic memory loss; non-fluent speech and/or visuospatial difficulties; executive dysfunction
Clinical presentation of AD in late stages
symptoms in early and middle stages, apraxia, apathy, paranoia
Macro or structural changes in brain with AD
progressive loss of connections between neurons and neurons themselves; brain shrinks; cerebral cortex shrivels and fluid-filled ventricles expand
2 microscopic changes in brain with AD
peptide amyloid-β or plaques accumulate between neurons and microtubule-associated protein tau aggregate into neurofibrillary tangles inside neurons, which persist afters neurons die
Prognosis of AD
typically starts in the medial temporal lobe 20 years before symptoms show the MCI converts into dementia within 4-8 years
4 ways to diagnose AD and their biomarkers
MRI (medial temporal atrophy); PET (tau ligand binding in medial temporal lobes); Cerebrospinal fluid (elevated phosphorylated tau); Blood (low Aβ42/40 ratios)
3 treatments for AD
acetylcholinesterase inhibitors (e.g. donzepil); glutaminergic antagonists (e.g. memantine); anti-amyloid antibody (e.g. aducanumab, lecanemab)
How effective is lecanemab?
very effective in clearing amyloid plaques compared to a placebo
Frontotemporal dementia
atrophy in the frontal and anterior temporal lobes in the brain
3 main variants of FTD
language, behavioral, motor
Clinical presentation of behavioral variant of FTD (bvFTD)
inhibition, apathy, social inappropriateness, executive dysfunction, anosognosia, preserved memory
2 primary progressive aphasia variants in FTD
non-fluent aphasia (halting speech with agrammatism) and semantic dementia
Semantic dementia
impaired confrontation naming, single-word comprehension, and object knowledge
2 ways to diagnose bvFTD
neuropsychological testing and social cognitive testing
Treatments for FTD
only symptom management due to diverse neuropathology each with different pharmacological agents needed
Clinical presentation of lewy body dementia
fluctuations in attention and awareness; visuospatial difficulties; hallucinations; parkinsonism (symmetric); REM sleep behavior disorder
Neuropathology of lewy body dementia
intracellular aggregation of α-synuclein especially in cortex, substantia nigra, limbic system, brain stem
Treatments for LBD
acetylcholinesterase inhibitors; L-dopa for parkinson’s symptoms; NOT antipsychotics
Clinical presentation vascular dementia
cumulative ischemic vascular disease and clinically symptomatic strokes; subcortical dementia profile; vascular risk factors; progressive or stepwise decline
Clinical presentation of subcortical dementia
cognitive slowing, executive dysfunction, language, preserved visuospatial processing