Recurring Topics

Question 1

The Ageing Brain: Neurodegenerative Disorders

Answer 1

• The best way to treat dementia/neurodegenerative disorders is to prevent them.
• Signs of dementia include - memory loss/changes in short-term memory, difficulty focusing, frequent mood changes, failing sense of direction, loss of general thinking abilities - significant enough to interfere with daily life.
• Alzheimer’s is the most common type of dementia = represents 60-80% of cases.
• 60% of the risk is gene-related but 40% is related to modifiable risk factors - which can be targeted to slow the development of the disorder.
• The past few decades have seen continuing increases in life expectancy, hence understanding the factors influencing healthy ageing has become an increasingly more prevalent concern (Kirkwood, 2017)

Question 2

The Cognitive Reserve Model

Answer 2

• Unlike the Brain Reserve Capacity Model, this model suggests that the reserve against brain damage is more active than passive (i.e., developed throughout the lifespan as opposed to innate)
• In essence, the model proposes that better cognitive reserve helps to protect against age-related changes in the brain. This is achieved by using pre-existing cognitive processing approaches to cope with damage. Higher levels of intelligence, educational and occupational attainment are potential predictors of which individuals can sustain greater brain damage before demonstrating functional deficit (i.e., people with high cognitive reserve cope better with pathology and remain clinically intact for longer).
• This delay in showing functional signs of neural deficits may be due to either neural reserve ( the individual’s brain networks are less susceptible to disruption, perhaps because they are more efficient or have greater capacity) or due to neural compensation (individuals turn to brain structures/networks/cognitive strategies not normally used by healthy people to compensate for the growing damage)
• Reserve may be structural (‘extra’ neurons and synapses, brain volume, head circumference or dendritic branching or arborization) or functional (a degree of excess capacity or compensatory mechanisms such that the brain could continue to perform well despite damage).
• Evidence for cognitive reserve comes from findings that there is a lower incidence of dementia in those with higher educational attainment (and slower functional/cognitive decline even from healthy aging), greater occupational attainment, less involvement in leisure activities, and in those with less extensive social networks. Notably, in Alzheimer’s patients who were matched for clinical severity, those with greater educational/occupational attainment died sooner. This supports the hypothesis - because they likely had greater brain damage than their level of clinical severity suggested.