degradarea in imbatranire Flashcards
what is the typical cognitive decline
since the age of 20 there is cognitive decline in most cognitive functions
e.g.
memory
reasoning
spatial visualisation
perceptual speed
what is pathological ageing
not all people age as well
modifications which take place due to age based illness, as independent from modifications correlated with typical healthy ageing
what is dementia
significant cognitive decline
Affects cognitive abilities
Dementia is heterogenous - different types of dementia will lead to different cognitive difficulties
Also associated with behavioural and psychological symptoms
What is the prevalence of dementia
7.1% of all ppl will develop dementia in their lifetime
There will be 1 million by 2025 and 2 million by 2050
what are risks for developing dementia
age
genetic facotrs
male
ethnicity
smoking
depression
high blood pressure
lack of excercise
diet/eight
what are the cognitive difficulties associated with different dementias
Alzheimer’s disease
-episodic memory
Vascular Dementia
-executive function
-attention and processing speed
what is the background of how Alzheimer’s disease was discovered
one of his patients has gone through 7 years of memory problems and confusion
he identified plaques and tangles after autopsy
what is AD
most common form of dementia
neurodegenerative - loss of neurones in the brain
slow, progressive, fatal, incurable
prominent episodic memory deficit - loss of personal unique recollection of experiences
What is the prevalence of AD
increases with age
84 year+ is 42% prevalance
How do you get a diagnosis of definite AD
you can’t be sure until autopsy until you look at the number of plaques and tangles
How do you get a diagnosis of probable AD?
Dementia observed
Cognitive impairment in memory and 1 other area
Decline progressive
Onset between ages 40-90
No other cause for symptoms
where does AD start
in hippocampus
atrophy of hippocampal formation
Study found that atrophy 2.5 times greater in AD than controls
what are causes of AD?
not fully understood
associated with age
plaques and tangles are present in temporal lobe which contains the hippocampus
what are plaques
-they form outside of neurones
-clusters of beta amyloid proteins
-plaques are not broken down normally and become insoluble
-they build up between neurones which affects
functioning
-block communication between neurones
how to plaques form
they form around amyloid precursor protein - which helps neurones grow and repiar
what are tangles
twisted fibres of protein tau within neurones
in a healthy CNS tau has important role for stabilising microtubules which transport nutrients around neurone
in AD tau protein is abnormal and microtubule collapses
cell dies due to lack of nutrients
what was found about brain in people with dementia
People with dementia had reduced blood flow in entorhinal cortex
Blood flow in entorhinal cortex is associated with memory tasks
They demonstrated cognitive difficulties primarily in memory
Memory is a hippocampal related task
what is vascular dementia
second most common type of dementia
150,000 ppl in UK
progression of symptoms
problems with blood supply to the brain
neurones rely on blood for oxygen and glucose
without they die
associated with damage to white matter and deep grey matter structures
symptoms of VAD
Memory loss not necessarily main presentation
main problems is executive function and attention deficits
What is the vascular dementia criteria
cognitive decline is due to decline from previous functioning
in diagnoses we are looking for impairment in 2 or more cognitive domains: executive function, attention, language, visuospatial, motor control, memory
physiological: evidence for cardiovascular disease, with or without stroke
what are causes of vascular dementia
based on damage to large OR small vessel disease
narrowing of blood vessels deep in the brain
gradual slowing of thinking and problem solving
What is the progression of vascular dementia
Progression from risk factors through cardiovascular disease to vascular dementia
Therefore preventable
what are the precursors of dementia
dementia is a gradual process
there are many steps preceding a dementia diagnosis
what is mild cognitive impairment (MCI)
Transitional stage before dementia
Not always converts to dementia
whats the conversion from MCI to dementia
not always
studies 105 patients with MCI over the course of 3 years
22% of them diagnosed with dementia
38% cognitive decline but not dementia
32% stable
8% showed cognitive improvement
What are the sub types of MCI?
Amnestic MCI
Non-amnestic MCI
What is Amnestic MCI
when memory is primary deficit
precursor to alzheimers
What is non-amnestic MCI?
memory is not major diagnoses
there is a decline in cognitive function but memory is not primary one
precursor to vascular dementia where executive function and attention is impaired
Why is much of the research conducted on people who have MCI rather than dementia
They are able to give consent
Actively take part in research - complete cognitive tasks
Have brain scans without sedation
How can we identify likelihood of conversion from MCI to AD?
compared resting state in fMRI machine
compared patients with AD, MCI and healthy adults
2.4 years later they followed up to see who has AD
fMRI distinguished MCI who converted to AD versus those who don’t
what are the early stages of vascular dementia
VaD is the result of cardiovascular damage
Usually referred to as small vessel disease (SVD)
A common presentation of SVD is a stroke
What is cardiovascular damage (SVD)
when there is major disruption of blood supply to brain causing a shortage of oxygen and glucose (ischaemic)
visible damage on MRI scans
a single large stroke can affect cognitive processes
SVD related to white matter damage
found progressive white matter damage in patients with SVD
so increase in white matter lesions (WHM)
What is test to distinguish between dementias?
Cognitive performance can distinguish between AD and VaD with 89% accuracy
Cognitive deficits in:
-episodic memory = AD
-VaD = executive function
what are things to consider about AD
although early AD sings are in temporal grey matter,
later changes occur throughout the brain,
affecting both grey and white matter
what are some things to consider about VAD and AD
although early primary cognitive deficits usually distinguish VAD and AD,
some studies have shown no difference on executive function task performance
by the time dementia occurs and progresses, cognitive difficulties are widespread
in late stage-dementia, there are fewer cognitive differences between different types of dementia
Does normal ageing brain also have plaques and tangles
normal ageing brain also has some plaques and tangles
Why has the purity of dementia been questioned
AD and VAD often co-occur
