1. The Ageing Brain
Fergus Doubal
October 2007

2. Plan
Age is a case of mind over matter – if you don’t mind it doesn’t matter (Wilde)
What matters most is function
Then structure – largely studied with MRI
Then functional imaging, cortical plasticity etc
Defining normal ageing difficult

3. Questions Forget science and evidence etc.
What do you think happens in normal ageing – to your granny, to your patients?
In your practice, what happens to brains on CT scans as age increases?

4. Fergus’ answers
Become slightly forgetful – ie forget where they put things, peoples names, perhaps unable to work new things eg remote controls
Brains seem to shrink on CT or rather on the ocasional young persons CT you see there seems to be quite a lot of brain (MCA)

5. Cognitive Function and Age

6. Cognition 1. Crystallised intelligence 2. Memory – short and long term
Cumulative end product of information acquired – vocab, knowledge based
2. Memory – short and long term
3. Cognitive speed – timed performance on perceptual tasks eg digit symbol subtraction

7. Canberra Longitudinal Study
10 years of testing old people
1. Crystallised intelligence – unchanged
2. Memory – decreases with age
3. Cognitive speed – decreases with age

8. What causes this decline?
Predictive factors are:
Education level,
High blood pressure
Poor health
Presence of APOE E4 allele
ANZ J Psych :

9. Brain Imaging Brain size (volumetric or scales)
White matter disease (volumetric or scales)
All on MRI

10. The Framingham Study for brain ageing changes
Currently consists of 2 cohorts – the original 1948 (5,000) and their offspring (5,000)
Predominately white middle class
Follow up ongoing
2,000 had brain MRI (cross sectional study)
Looked at regional brain volume, WMH and silent infarcts (those w neurol d excl)

11. Findings Men had bigger brains than women (but not after correction)
Before 50 age did not affect brain size
After 50, age explained 50% of volume loss – frontal and temporal lobes affected the most.
No differences between men and women
Infarcts unsurprisingly assoc w volume loss

12. Brain atrophy
Can be measured with scale (0-4) or volumetrically

13. Neurobiology of Aging Information Center
2% reduction in weight/volume per decade
Not due to neronal loss but shrinkage
Frontal lobe affected in normal ageing
Hippocampus (and perhaps different areas within the HC) affected in AD – mention dentate gyrus and entorhinal cortex

14. WMH Seen as hyperintensities on T2 MRI Common Assoc w hypertension,
Assoc w cognitive function
Progress w age – best predictor is baseline WMH
Assoc w lacunar stroke and cerebral microhaemorrhages
Fine when looking at path etc but how do they relate to individual patients
Could they be used as a surrogate marker for trials in vasc cognitive impariment

15. WMH – non confluent

16. WMH – confluent

17. Neurobiology of Aging Information Center
Connections – decrease, may account for cognitive slowing
ACh and dopamine decrease w age
But brain retains plasticity – ability to make new connections after insult as seen with stroke and then devastaing effects of bilateral strokes

18. Summary Crystallized intelligence remains
Memory and cognitive speed decrease
Brains shrink w regional variation
White matter hyperintensities increase.
To relate back –your granny will become more forgetful and her brain will shrink