cognitive ageing Flashcards
Cognitive Ageing: ‘Normal’ Decline
- Slower thinking
- Slower doing
- Hesitating more
- More likely to think before acting
- Knowing the person but not the name
- Pausing to find words
- Being reminded of the past
Cognitive Ageing: Not ‘Normal’ Decline
- Not thinking the same
- Not doing the same
- Can’t get started
- Thinking but not acting
- Not knowing the person
- Not being able to find words
- Confusion about past versus now
What is Negatively Affected by Cog Ageing?
- Memory (particularly working memory)
- Reasoning
- Attention
- Visual processing
- Reaction time/processing speed
Biology Behind Cog Ageing
- white & grey matter deteriorate with age
- white matter loss may be responsible for many typical symptoms - ‘fluid intelligence’
- decrease in plasticity
What is Grey and White Matter
Grey Matter:
* in the cerebrum
* creates the cerebral cortex
* responsible for conscious perception of movement, sensation, & association between the two
White matter:
* in the cerebrum
* connects areas of the same or different hemispheres
* communicates with the spinal cord
Where Does the ‘Use It or Lose It’ Idea Come From?
Brain Plasticity
4 Ways
Ways to Reduce Cog Ageing
- develop new skills earlier in life
- early IQ
- hobbies & lifestyle choices
- gaming
Preventing Cog Ageing: Evidence for Developing New Skills Earlier in Life
- Maguire, Woollett, & Spires (2006) found large hippocampi in London taxi drivers
- Draganski et al., (2004) found growth in ppts who learned to juggle
- Boyke et al., (2008) replicated with ppts aged 50-67
What Impacts Early Decline?
- early IQ
- exercise
- hormones
- vitamins
- diet
What is Homocysteine?
Homocysteine is an amino acid produced when proteins are broken down
What is the Normal Level for Homocysteine in the Blood?
A normal level of homocysteine in the blood is less than 15 micromoles per liter (mcmol/L) of blood
What do High Levels of Homocysteine in the Blood Indicate?
High homocysteine levels usually indicate a deficiency in vitamin B-12 or folate
How can High Levels of Homocysteine Affect Cog Ageing?
- high levels may increase the risk of cardiovascular disease - a risk factor for dementia
- this happens by promoting silent brain infarcts and atherosclerosis, causing cognitive impairment
- high levels may also produce neuronal cell damage by activating N-methyl-D-aspartate receptors
The Effect of Oestrogen on Homocysteine
Oestrogen lowers homocysteine levels
Evidence for Oestrogen Lowering Homocysteine Levels
Lakryc et al (2015):
* 20.7% reduction in homocysteine levels after 6 months of unopposed oestrogen therapy
* 2.2% decrease in homocysteine levels after 6 months of oestrogen-progestin therapy
* data suggests that hormone therapy may have a positive influence on decreasing cardiovascular risk due to a significant reduction in homocysteine levels
What Do Oestrogens Do in the Brain?
- stimulate cerebral blood flow, glucose uptake
- stimulate branching dendrites (through NGF)
- influence factor that affects neuronal death/survival & function
- modulates NT release & receptors
Describe the Cycle of Homocysteine Metabolism
S-adenosylmethionine (acceptor)
-> S-adenosylhomocysteine (methylated acceptor)
-> Homocysteine (B6->Cystathionine->B6->Cysteine)
-> Folate (B12)
-> Methionine
3 Substances which can Lower Homocysteine Levels
- oestrogens
- folic acid
- vitamin B12
Evidence for Folic Acid & B12 Lowering Homocysteine Levels
Homocysteine Lowering Trialists’ (HLT) Collaboration (1998):
* meta-analysis of 12 randomised controlled trials
* 0.5-5mg folic acid reduced homocysteine by 25%
* 0.5mg B12 reduced homocysteine by +7%
* (vitamin B-6 (mean 16.5 mg daily) did not have a significant additional effect)
Interventions to Reduce Cog Ageing
- encouraged as lifestyle choices - especially effective if adopted early
- exercise - particularly sport-based
- healthy eating
- cognitively engaging hobbies - e.g. chess
- two prep papers – music and language
Interventions = i.e. lifestyle choices such as exercise
What Do Interventions Cause which Reduces Cog Ageing?
Build a buffer called ‘cognitive reserve’
Cognitive Reserve
- you (or most of you) engage certain areas when completing complex cognitive tasks
- frontal lobe decays heavily with age, but some older people still perform well on these tasks - Why?
- cognitively engaging hobbies and lifestyle have kept them sharp, which means they can recruit extra brain areas
- They have built up a reserve of cognitive support
- But these activities only engage certain aspects of cognition – can we improve overall with just one measure?
Which aspects of Cognition can be Improved by Gaming?
- working memory
- spatial awareness
- abstract reasoning
- reaction time
- distraction control
- plasticity
Gaming: The Effect of Action Games on Cognition
- force the player to filter out distracting info - building cognitive reserve (top down vs bottom up)
