L1 - Memory systems (diagnosis of AD)

Question 1

What tests can be done to diagnose Dementia?

Answer 1

• General physical examination / neuro exam
• Cognitive testing
• Brain imaging
• EEG
• Genetic testing
• Blood / CSF biomarkers
• Post-mortem confirmation

Question 2

Talk about GPs ability to recognise and diagnose dementia?

Answer 2

GPs have very low PPV (positive prediction value) of only 54.8%

NPV is much better at 97.2%

The message - were not good at diagnosing dementia

Question 3

Why are EEGs good for diagnosing dementia?

Answer 3

• Measures brain activity/function in real time
• Cheap, well tolerated, fast and non-invasive
• Likely the first affected parameter in dementia
• Applicable to humans and animal subjects (good 4 science)

Question 4

On EEGs - brain wave things come in different frequencies

What type of brain activity is associated with:

a) Low frequency (delta) waves
b) High frequency (beta-gamma) waves

Answer 4

a) Low frequency (delta) waves are seen when the brain is at rest - ie not engaging with cognitive processes
b) High frequency (beta-gamma) waves associated with engaged brain networks

Question 5

What EEG changes can be seen in dementia (specifically AD)

Answer 5

Reduced high frequency (beta-gamma) brain waves (= reduced cognitive engagement)

Increased low frequency (delta) brain waves (= increased brain ‘resting’)