Neurobehavioural variables in assesment

Question 1

What disease variables can affect clinical assessment?

Answer 1

1. Generalised effects
2. Disconnection/diachisis
3. Plasticity

Question 2

What subjective variables can affect clinical assessment?

Answer 2

1. Premorbid competence

2. Emotion and cognition

Question 3

What are generalised effects?

Answer 3

• Brain lesions can cause swelling and compression of other brain areas, creating diffuse effects away from lesion area
• Early stages of focal brain disease resemble each other in terms of cognitive impairments in memory, executive function and reasoning

Question 4

What is diachisis?

Answer 4

Loss of function in brain area that is anatomically intact due to loss of input from damaged area

Question 5

Give an example of diachisis

Answer 5

Parkinsons
- Only a small area damaged (substantia nigra) that affects function of basal ganglia, thalamus and neocortex as they stop receiving dopaminergic input

Question 6

What is disconnection?

Answer 6

Disorder of pathways (white matter) between brain areas which can occcur in demyelinating diseases such as multiple sclerosis

Question 7

Give an example of disconnection and its effect

Answer 7

Interhemispheric disconnection done in patients with severe epilepsy

• Present word to left and right, ask patient to say word they see and pick up corresponding object with left hand
• Say word presented on right (left hemisphere is language dominant) and as left hand is controlled by the right they pick up object presented on the left (hemispheres cannot share information)

Question 8

What is plasticity?

Answer 8

Reorganisation of brain functional modules where healthy tissue takes over function of the lesioned area

Question 9

Give an example of neuronal plasticity?

Answer 9

Left sided functional hemispherectomy (removal of left hemisphere) in epilepsy patients

• Left side believed to be language dominant
• However patients with this procedure, 23 had unchanged cognitive ability and 4 had improved cognitive and language ability
• Brain adapts to loss

Question 10

What is cognitive reserve?

Answer 10

• Individual variability in clinical outcome of brain pathology
• High reserve patients may have a later change point after which decrease in cognitive status is detected

Question 11

Give an example of high cognitive reserve

Answer 11

‘Silent stroke’

• Patient was giving out faulty building permits, was unaware that he was doing wrong
• Tested normally in verbal tests and was alert and aware
• However bed results on contruction tests
• Revealed that he had suffered a large stoke

Question 12

What has been linked with cognitive reserve?

Answer 12

• Education and participating in social events/hobbies

- Brain games can help improve certain cognitive domains in the elderly however no causal link has been established

Question 13

What test is often used to test for intelligence?

Answer 13

WAIS tests

Tests episodic memory, working memory, verbal comprehension, processing speed, perceptual reasoning etc.

Question 14

What are the features of the WAIS test?

Answer 14

• One of the most complete and highly used tests
• Very long and thorough (therefore requires time and skill to administer)
• well standardised with good inter-reater reliability and accuracy

Question 15

What WAIS tasks test verbal comprehension?

Answer 15

General knowledge questions, voabulary test, similarities test (explain relationship between incresingly abstract words)

Question 16

What WAIS tasks test perceptual reasoning?

Answer 16

block design (recreate pattern using an increasing number of blocks), matrix reasoning (what image best fits the sample), visual puzzles (3 components to complete image)

Question 17

What WAIS tasks test working memory?

Answer 17

“Repeat back to me” and arithmetic

Question 18

Is there a genetic element to intelligence?

Answer 18

Yes - twin and adoption studies suggest a 30-80% heritability of intelligence, however no gene specifically implicated
No - adopted vs non-adopted sibling, adopted sibling shows higher IQ when adopted by ‘intelligent’ family

Question 19

Are there nenuronal correlates of intelligence?

Answer 19

Voxel-based morphometry shows neuronal correlates (increased cortical thickness) of “g” more on the left hemisphere

Question 20

How can emotion and cognition interact?

Answer 20

• Depressed patients have a decreased memory
• Decrease hippocampal volume which is correlated with the length of depressive episode
• Not due to lack of effort/motivation

Question 21

When can cognitive and emotional effects interfere with diagnosis?

Answer 21

In elderly, dementia and and depression are hard to distinguish

Question 22

What components are encompassed in a full-scale IQ score?

Answer 22

• Perceptual reasoning
• Working memory
• Verbal comprehension
• Processing speed
• Semantic memory
• Episodic memory
• Procedural memory

Question 23

How does WAIS test processing speed?

Answer 23

• Through a symbol search, finding a target in a busy image

- ‘Coding’ presented with a symbol legend, must fill in blank spaces with correct symbol