Dementias Flashcards
Why do we have more age related diseases than ever before?
Increased medical care awareness and disease research has created an ageing population, which results in people living longer and being at greater risk for dementia
What is dementia?
A group of disorders associated with global declines in cognitive and behavioural functioning
What is the greatest risk factor for dementia?
Age, the risk of getting dementia increases linearly from age 65
Why would it be good to find a cure or prevention for dementia?
It has a large economic impact, because it allows people to work for longer. It also relieves a massive social burden.
What is successful ageing?
Living as long as you can, as healthily as you can.
How does variability in cognitive functioning work, age wise?
It’s like a two mouthed vuvuzela, there is a lot of variation with children, it levels out more or less with adults and then variation increases again in the older generation
Two causes of cognitive decline
Brain diseases associated with ageing or normal age related declines
Relationship between normal ageing and dementia
It’s not a continuum, there are qualitative differences
What is crystallised intelligence?
It’s semantic knowledge gained from books that increases with a diverse range of experiences
How is crystallised intelligence affected by age?
It changes only slightly
How does crystallised intelligence play a role in preventing dementia?
Crystallised intelligence forms a functional cognitive reserve, which creates a barrier through which the dementia has to break before it can set in.
Examples of functional cognitive reserve
Nun study: women who wrote with more complex vocab in their twenties were less likely to have developed dementia in their older years
Scottish study: adolescent IQ tests done nation wide and found that kids who scored higher in these were less likely to develop dementia
What is fluid intelligence?
Abilities like novel reasoning, adaptability and response to abstract ideas.
How is fluid intelligence found and its relation to age
It’s unrelated to formal education, strongly related to biological factors. It shows definite changed as people age.
What are the three most reliable declines in cognition?
- Processing speed
- Abstract and complex new problem solving
- Memory and new learning
Aspects of memory affected by ageing
- Decline in free recall, partly due to poor encoding
- Decline in working memory
- Decline in less contextualised and effortful tasks
Four aspects of memory that remain intact with age
- Storage processes
- Performance on recognition tasks
- Procedural memory tasks
- Short term memory
Age related structural changes in the brain
- Loss of weight and volume
- Flattening of cortical surfaces
- Widening of ventricles
Neuronal age related changes (6)
- Shrinking and death of ageing cells
- Loss of dendritic processes
- Neurofibrillary tangles
- Neuritic plaque
- White matter abnormalities
- Grey matter loss
Regions vulnerable to age related brain changes
- Hippocampus
- Frontal lobes, mostly PFC
- Temporal and parietal association areas
Regions preserved in age related brain changes
- Occipital cortex
- Somatosensory cortex
Grey matter atrophy patterns
Cortical atrophy varies, grey matter atrophy, plaque and tangles are not invariably associated with dementia, particularly in ages 84-90.
Genetic and environmental factors in dementia
The apoE4 gene, the one linked to Alzheimer’s.
Stress, affects the telomeres and cortisol and hippocampal vulnerability
Exercise
What is the differential preservation hypothesis?
There are individual differences in how well a person is going to age, and these stem from how active a person is both physically and mentally, the activity can be started later in life.
This suggests that staying active will allow you to maintain your cognitive functions.
What is the preserved differentiation hypothesis?
Individual differences stem from cognitive reserve, which suggests that those who performed physically and cognitively when they were younger are better off with successful ageing.
What neuronal changes are always associated with dementia?
- Grey matter atrophy
- Plaque
- Tangles
What is mild cognitive impairment?
A stage of cognitive impairment that indicates that a person is not cognitively intact but does not meet the criteria for dementia
Three criteria for mild cognitive impairment
- Objective cognitive problems: 1.5 std dev below the mean
- Subjective cognitive problems: complaints of cognitive function loss
- Intact ADLs: daily living functions are fine
Mild cognitive impairment and dementia
MCI doesn’t always lead to dementia. But there is an increased risk of developing it and it will occur at a faster rate.
Three different types of MCI
- Amnestic - only memory impaired
- Vascular - only executive functioning is impaired
- Multiple domain - more than one cognitive domain is impaired
Nature of amnestic MCI
There are deficits in encoding and retrieval, like Alzheimer’s. Other cognitive areas and activities of daily living are intact. Damage is in the hippocampal atrophy
Definition of dementia:
A behavioral syndrome, not one disease. It includes multiple conditions, with a variety of aetiologies.
How are dementia subcategories defined? (3)
- Site of damage
- Cause
- Suspected disease
Classifications of dementia
- Cortical vs subcortical
- Static vs progressive
- Reversible vs irreversible
Cortical vs subcortical dementia
Cortical: primary effects in the cerebral cortex and grey matter structures. Alzheimer’s.
Subcortical: primary effects in the white matter and subcortical grey matter
Problems with the cortical vs subcortical dichotomy
Dementia does not conform to boundaries and at the very end stages, most dementia looks the same
Static vs progressive dementia
Static: steady state cognitive disorder, it won’t decline once arrested. Caused by infection or neurotoxic substance
Progressive: it only gets worse, caused by the disease process. Alzheimer’s
Reversible vs irreversible dementia
Reversible: decline in functioning gets reversed and goes back to baseline functioning
Irreversible: usually seen with progressive dementia, Alzheimer’s
Two different sets of diagnostic criteria for dementia
DSM-IV-TR and NINCDS-ADRDA
Agreed upon criteria for dementia (from DSM-IV-TR and NINCDS-ADRDA)
- Loss of cognitive or intellectual functioning
- Multiple areas of cognitive impairment
- No confusion or disorientation (it’s not delirium)
Classification of Alzheimer’s
Cortical, progressive and irreversible
Epidemiology of Alzheimer’s
It’s found globally, and is the most prevalent of the dementias. The incidence of it increases with age.
Risk factors for Alzheimer’s
- Age
- Sex
- Education
- Genetics (ApoE4)
Diagnostic criteria for Alzheimer’s
- Behavioural presence of dementia (see a change of personality, irritable and aggressive)
- Identification of neuropathological markers
- Definitive diagnosis can only be made on an autopsy
Diagnostic problem with Alzheimer’s
It’s overdiagnosed because people don’t distinguish between AD and other dementias
If I looked at an MRI of a person with Alzheimer’s, what would I see?
- Large ventricles
- Neuron loss
- Dark spots on hippocampi
Presentation of early stage Alzheimer’s, functions impaired:
- Recent memory
- Delayed recall
- Visuospatial abilities
- Naming
Presentation of early stage Alzheimer’s, functions intact
- Receptive language
- Expressive language
- Strength
- Motor and processing speed
- Executive function
