CCC- Dysexecutive syndrome Flashcards
What does the primary motor cortex do?
Production of skilled movements
What does the premotor cortex do?
Organization of more complex actions
What does the prefrontal cortex do?
Controlled behaviour
What does the dorsolateral prefrontal cortex do?
inhibition, planning, working memory
What does the ventrolateral prefrontal cortex do?
Emotional control/regulation
Role of the prefrontal cortex in cognition
What do the frontal lobes mediate?
Mediate “higher” cognitive functions, and the co-ordination and strategic use of other cognitive resources
These are commonly referred to as “executive functions”
What are some examples of executive functions?
Organizing, planning, prioritizing
Making decisions, thinking strategically
Deploying attention, focusing, following a plan
Monitoring performance, actions
Multi-tasking, task switching, inhibition
Problem-solving, abstract thinking, integration of knowledge
Working memory, prospective memory, future thinking
Regulating emotions, appropriateness to the context
What causes disexecutive syndrome?
Damage to the frontal lobes- (damaging executive functions)
What are the common reasons for prefrontal damage?
Traumatic brain injury (TBI)- (e.g. car crash)
Stroke or rupture of aneurysm of anterior communicating/cerebral artery
Tumor (e.g., meningioma)
What happened to Phineas Gage?
1848: 25 years old, railroad construction foreman
An accident caused penetrating head injury – a metal bar went up through his eye and skull
A few hours later he was able to speak to the doctors
Two weeks later his memory for familiar people and recent events was intact
Survival for another 11.5 years
Haemorrhage and infections damaged particularly the ventromedial prefrontal cortex
What was Phineas Gage like after the injury?
He could perform normal actions in day to day life
Personality changed in bad way
Couldn’t keep a job/ kept losing them- wouldn’t go back to life like it was before.
Cognitive and behavioural changes- considered unpopular & weird.
What area of the brain was damaged for Phineas Gage?
Ventromedial prefrontal cortex
What is Utilisation behaviour?
The tendency to grasp common objects when presented, and perform the function commonly associated with the object.
Indicates lack of appropriateness to the context, impulsivity.
Individuals with prefrontal damage find it difficult to resist the impulse to use the objects in front of them, even when these actions are not appropriate to the situation.
What are examples of executive dis-functions?
Inability to organize and plan
Distractibility
Inability to inhibit prepotent responses, impulsivity
Inability to switch/shift focus
Inability to solve complex problems, think in abstract ways
Inability to make farsighted decisions
Inability to envision future situations
Inability to respond the context appropriately
What is a way of testing executive functions?
Wisconsin Card Sorting Test (WCST)
Tests: set-shifting, rule abstraction, flexible thinking
3 possible ways of categorising stimuli: number, colour, shape
Task: learn what is the correct rule to categorise stimuli based on feedback
Wisconsin Card Sorting Test (WCST)
How did individuals with prefrontal damage do on the task?
What is the behaviour referred to as?
Individuals with prefrontal damage get “stuck”, carrying on sorting by a rule even if told it was wrong.
This behaviour is referred to as perseveration (Milner, 1963)
What other test other than the Wisconsin Card Sorting Test (WCST) can be used to test executive functions?
How do individuals find this test?
Stroop test!
Individuals with prefrontal damage cannot inhibit the more prepotent, automatic response of reading the words, despite knowing their task it to name the colour of the ink the word is written with.
What does the Hayling test do?
Tests: response inhibition and strategy generation
A series of sentences are read with the last word missing
“The captain wanted to stay with the sinking…”
“He posted the letter without a…”
Part A: complete the sentence with an appropriate word – “ship”/ “stamp”
Part B: complete the sentence with an unrelated word – e.g., “chair”/ “blue”
How do individuals do in the Hayling test?
Individuals with prefrontal damage cannot inhibit the automatic response of completing the sentence with the obvious word.
They also cannot generate a strategy to find unrelated words
(e.g., listing words belonging to a certain category).
Testing Executive functions
What are the pros/ cons/ discussion
Some individuals will perform well on tests of general IQ, attention and even traditional tests of executive function but…
They are disorganised in their daily life – e.g., poor at making a plan and sticking to it
Most lab-based tests are very structured vs real life situations are not well structured
Tests need to be open-ended, require multi-tasking and planning
Ecologically valid tests predict functioning in “the real world”
What is the Multiple Errands Test?
Shallice & Burgess, 1991
Tests: planning, strategy thinking, problem-solving
6 simple tasks (e.g., buy a brown loaf, buy a packet of throat pastilles)
A seventh task requires the subject to be at a certain place 15 minutes after starting
An eighth task requires to obtain four sets of information and write them on a postcard (i.e., the name of the shop in the street likely to have the most expensive item; the price of a pound of tomatoes; the name of the coldest place in Britain yesterday; the rate of the exchange of the French franc yesterday).
Takes place in the real world (in a small shopping precinct near the hospital previously unknown to the patients)
Requires to obey various rules
Only go into each shop once
Only use a watch to assist you
Stay within a certain area
Spend as little money and time as possible
How did healthy controls do in the Multiple Errands Test?
How did the individuals with pre-frontal damage do?
They managed to do all the tasks in the right amount of time- went to post office when tasks completed & didnt spend much money.
Went back and fourth to shops- didn’t do stuff in right order- behaviour was disorganised- cant plan schedule & stick to plan- found hard to focus attention on the list of tasks they had to do- didn’t stay within the boundaries.
The Multiple Errands Test
What errors were typically made by patients with prefrontal damage?
Plan formulation or modification
Going to Post Office before all relevant information obtained (Cases 1-3)
Failure to look at watch at start (Case 3)
Generation of inappropriate criteria
Marker creation or triggering
Going out of bounds (Cases 2, 3)
Attempt not to pay for item in shop (Case l, 2)
Looking in irrelevant shops (Cases 1, 2)
Evaluation and goal articulation
Posting postcard without all information (Cases 2, 3)
Failure to keep a check of money (Cases 2, 3)
Thinking finished when had not (Case 1)
What is a theory which explains Prefrontal Damage?
Supervisory attentional system (SAS)
Norman & Shallice, 1986
