Perception, Planning and Action: Deficits in Planning

What the frontal lobes are involved in
(1) Motor Functions
(2) Higher Order Functions
(3) Planning / Impulse Control
(4) Reasoning / Problem solving
(5) Memory
Phineas Gage (1848)
- 25 year old railroad worker
- Accident caused a metal rod to pierce his brain (orbito-frontal areas, Damasio et al., 1994)
- Survived accident but Gage's behaviour had 'changed'
- Behaviour post-accident suggests that frontal lobes are involved in the planning and maintenance of behaviours
Phineas Gage prior to accident
- Gage was 'shrewd, smart businessman...'
- Persistent in executing all his plans of operation
- Efficient and capable
Phineas Gage post-accident
- "vulgar... intolerable to decent people"
- "Impatient of restraint or advice when it conflicts his desires"
- Abandoning "future plans for others that appear more feasible"
- Entertained nephews with "fabulous recitals of his wonderful feats" that were not true
Saver and Damasio (1991) - Patient EVR
- Operation removed parts of the frontal lobes
- High IQ
- Developed socially abnormal behaviour
- Had problems planning and organising life
- Relationships suffered
- Bad financial decisions leading to bankruptcy
- Much deliberation on simple decisions
Karpov et al (1968)
- Asked a patient to scan a picture to answer a specific question e.g. how old are people in the painting?
- Frontal lobe patient had difficulty modulating eye movements
- Failure to adopt or generate an appropriate strategy
"Executive" function of frontal lobes - Luria (1966)
-Frontal lobes responsible for...
- Programming and regulating behaviour
- Verifying whether behaviour is appropriate for a situation
- Frontal lobe patients may therefore have problems with this
Normal & Shallice (1986)
- Developed the idea of the executive
- Responses can be controlled by different ways
Automatic/Partially automatic control (Norman & Shallice)
Triggered by environmental factors
Willed Actions (Normal & Shallice)
- Supervisory Activating System
- More complex routine control is insufficient (e.g. in novel situations)
SAS may help with
(1) Planning or decision making
(2) Error correction / trouble shooting
(3) Responses that are not well learned
(4) Novel actions
(5) Responses that are technically difficult or dangerous
(6) Overcoming strong habitual response/resisting temptation
If there are problems with the SAS
(1) Automatic actions will persist until inhibited by the SAS so if damaged, these actions will continue
(2) Rigid, inflexible behaviour
(3) Patients respond inappropriately in some situations
Neuropsychological Evidence for the SAS
(1) Wisconsin Card Sorting Task (WCST)
(2) Perseveration
(3) Fluency Test
(4) Alternate Uses Test
(5) Utilization Behaviour
(6) Hayling Sentence Completion Test
Wisconsin Card Sorting Task (WCST)
- Patients asked to sort cards by a rule
- Rule can be sort by "colour", "number", "shape"
- After sorting by the rule for 6-10 consecutive times, the rule changes and participants need to sort by a different rule
- Frontal lobe patients continue to sort by old rule despite being told it's wrong
- Patients show behavioural rigidity
Perseveration (Luria (1965)
- Unable to inhibit actions
- E.g. continue to draw circle until pen is taken away
- When patient asked to write a dictation and then draw they blend the letters and picures
Fluency Test
- Patients with frontal lobe problems have big problems generating a list of words beginning with a certain letter
- Often perseverate with the same word or derivatives of that word
- Patient L.E. said 3 words beginning with F in 60 seconds
Alternate Uses Test
- Think of an atypical use for an everyday object
- Patients have problems inhibiting the automatic response
- Stroop Task
- Asked to name the colour of the ink
- Sometimes the word is incongongruent to the colour of the ink
- Have to ignore word to respond correctly
- Frontal lobe patients perform poorly (due to increased distraction)?
Utilization Behaviour
- Reach out and use objects that are within their reach
- E.g. If glasses are on the table, reach out and put them on (even if not theirs)
- Objects afford a response
SAS and Utilization Behaviour
- Perceptual input leads to activation of "action schema"
- If no SAS then these actions are carried out
- No inhibition of action schemas triggered by perceptual input
Tower of London Task
- Participants have to move disks to match goal position
- Do this in certain number of moves
- Requires forward planning
- Owens et al (1990) - Patients fine at making the first move
- But took more time than controls on subsequent moves
Hayling Sentence Completion Test
- Patients presented with a sentence to complete -
- In task A - respond with correct word "the captain wanted to stay with the sinking...(ship)"
- In task B - respond with a nonsensical word "the captain wanted to stay with the sinking..(mustard)"
- Frontal lobe patients delay in response to task A and find task B very difficult
More sensitive measures of frontal lobe problems
- Deficits in strategy application
- Real life situations
- Problems with Neuropsychological tests
- Six Element Test
- Multiple Errands Test
Deficits in Strategy Application
- Some patients show fine performance on neuropsychological tests but are impaired on everyday activities where patients need to plan behaviour over longer times
Problems with Neuropsychological Tests
(1) The patient only has one problem to tackle at a time
(2) Trials are short
(3) Clear goals - know exactly what is to be achieved
Real life situations
- Multiple goals
- Tasks generally longer than a minute
- Many ways to do a task (often no clear goal)
- Sometimes have to overcome problems
Shallice & Burgess (1991) New tests
- Constructed tests to investigate more open-ended multiple goal situations
- Investigated with 3 patients
Shallice & Burgess (Case 1)
- AP, 23, traffic accident - bi-frontal damage
- Severe organisational difficulties in everyday life
- Unable to shop for himself - buy one item at a time and return to his car between buying items
- Fine IQ and on WCST, stroop task, verbal fluency and tower of London
Six Element Test
- Investigates patients ability to complete 6 tasks in 15 minutes
- E.g. dictating a route; arithmetic problems
- Patients performed below normal range on these tasks
Multiple Errands Test
- Mirrors everyday tasks
- Go to busy shopping precinct and perform various simple tasks
- Being in a certain place 15 mins after the task started
- Patients found these tasks difficult
- Performed worse than controls
- Inefficient in time
- Broke rules
- Failed tasks
- Interpretation failure of rules
Real-life tests require
- Maintenance of goals and intentions and planning
- In these tasks need to plan on-line in relation to environment
- Cannot carry out these tasks by "routine actions" this need SAS
Real-life tests highlight the need for the SAS to be involved in
- Goal articulation
- Provisional Plan Formation
- Evaluation of process
- Plan modification
Goldstein et al (1993)
- 51 year old patient undergone left frontal lobectomy
- Patient had difficulty making decisions
- No significant changes in IQ or memory
- Fine on WCST, Hayling sentence completion task & Six Element Test
- Less efficient than control on Multiple Errants Test
- Broke rules of tasks
- Deficit in strategy application most likely due to impaired SAS
- Multiple Errands Task more sensitive measure of frontal love impairment