Post on 15-Nov-2021
transcript
11/6/2015
1
Clinicians Beware!Appearances May Be Deceiving
Donald T. Stuss, PhD, Founding President and Scientific
DirectorOntario Brain Institute
Financial Disclosure
I have no financial relationships to disclose:
• Mick Alexander, Tim Shallice, Terry Picton,
• Antonio Valessi - fMRI
• Susan Gillingham, and a host of others
• Funders: CIHR, OMHF
ACKNOWLEDGMENTS
Share with you for consideration and discussion
some 35 years of lessons learned in the study of
individuals with frontal lobe dysfunction on why to
be wary when you study, diagnose and treat such
individuals
Overarching Objective
4
• Identify and differentiate the four major categories of frontal lobe functioning
• Map the relationship between anatomical development and connectivity to frontal lobe functions
• Identify how “basic” research can be used for the development of neurorehabilitation techniques to patients with frontal lobe dysfunction
Specific Learning Objectives
5
Examples of the “Mystery” of the Frontal lobes
Research findings that shed some light
The value of these findings to clinical application
Summary of the Lessons
OUTLINE
6
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• Clinical investigation of the frontal lobes has led to many “teachings” that we use for diagnosis
• Using clinical examples, will highlight the reasons for wariness in diagnosis and indeed even understanding the frontal lobes – perhaps because we view the individuals through our cognitive and clinical models
• Through this, will summarize lessons learned7
THERE IS A REASON WHY THE FRONTAL LOBES WERE CALLED A MYSTERY
Examples of the “Mystery” of the Frontal lobes
Research findings that shed some light
The value of these findings to clinical application
Summary of the Lessons
OUTLINE
8
MYSTERY # 1 - GAGE ET AL.
• “No longer Gage” – “the equilibrium ..betweenhis intellectual faculty and animal propensities,seems to have been destroyed.”
• Ackerly & Benton (1947) – congenital bilateral prefrontal lesion. As he grew, significant problems in emotional control
Figure 1. Modeling the path of the tamping iron through the Gage skull and its effects on white matter structure.
Van Horn JD, Irimia A, Torgerson CM, Chambers MC, et al. (2012) Mapping Connectivity Damage in the Case of Phineas Gage. PLoS ONE 7(5): e37454. doi:10.1371/journal.pone.0037454http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037454
EARLY REPORTS – BUT…
• Gage
a) The most dramatic changes occurred in early stages post-injury, and decreased
b) Many of the reports apparently exaggerated (Macmillan)
c) Gage could hold a job – but not consistently
• Ackerley & Benton – patient could hold a job under certain circumstances
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IMPLICATIONS
• There are subtleties to study and understand, which are important for rehabilitation and management
• Context (time since injury, environmental circumstances) appears particularly relevant
MYSTERY # 2 – LEUCOTOMY STUDIES
• In the mid 1970s we studied the effects of pre-
frontal leucotomies 25 years post-surgery
GROUP DESCRIPTIONS
• Five groups of individuals were studied:
• Matched control group
• Four patient groups from the same hospital, diagnosed by the same physicians as psychotic
• Three groups had received a frontal leucotomy as treatment; sub-divided into three groups based on degree of recovery: good, moderate, poor
• The fourth – no surgery even though one had been prepped
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EMOTIONAL SITUATIONS TEST
8
0
1
2
3
4
5
6
7
I II III IV V
I Good RecoveryLeukotomy
II Moderate RecoveryLeukotomy
III No RecoveryLeukotomy
IV NonleukotomizedSchizophrenics
V Controls
LEUCOTOMY IMPACTS SOCIAL BEHAVIOURS - BUT….
• The Boston bus station
• Going dancing
• Catatonia and a sense of humour
• Changing neuropsychological examiners -a lesson about social behaviour
IMPLICATIONS
• Social changes are not an all-or-nothing phenomenon
• There are qualitative differences in abnormal social responsiveness
• Context again is important
MYSTERY # 3 – MORE LEUCOTOMY
• During the leucotomy research, DF Benson was on sabbatical at the Maudsley in the UK
• The Context
• My Response:– even though I had not analyzed the data, I had been working with these individuals for months. I was trained as a clinical psychologist before neuropsychology – I was a confident observer and diagnostician.
• FRANK, TRUST ME – the major deficit after frontal leucotomy is a severe attentional deficit
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BUT…
• THEN – I ANALYZED THE DATA
26
SPAN TESTS
0
1
2
3
4
5
6
7
8
I II III IV V
Mean Span
Length
Group
Digit Span
Forward
Backward
Stuss et. al., 1981
0
2
4
6
8
10
12
14
I II III IV V
Mean Trials Correct
Group
Knox Cube
I – Good RecoveryII – Moderate RecoveryIII – No RecoveryIV – Schizophrenic ControlsV – Normal Controls
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ATTENTION MEASURES
0
50
100
150
200
250
300
350
400
Time Time Errors Time A Time B Errors B
Tim
e
I - Good Recovery
II - Moderate Recovery
III - No Recovery
IV - Schizophrenic Controls
V - Normal Controls
Count by three
Serial sevens Trail-makingStuss et. al., 1981
IMPLICATIONS
• What you see is not necessarily indicative of theactual abilities; it may represent the unfolding ofabilities under certain contexts
• You can become the frontal lobes of the patient, compensating for the problems – and this itself is a type of context
MYSTERY # 4 – PSYCHOSIS OR NOT
• Canadian volunteer to US Army in Vietnam way discharged for psychiatric reasons
• One year later – recalled
• The day before recall – ended up in hospital with tentative diagnosis of acute psychotic reaction with catatonic symptoms
• Description of patient examination
• Lesion – small left posterior frontal ventrolaterallesion
IMPLICATIONS
• One more lesson on the importance of under-standing context when you examine a patient
• Lesion location within the frontal lobes is important
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MYSTERY # 5 - TBI CASE STUDY
• Patient suffers mild-moderate TBI. After initialrecovery, has normal intelligence, attention,language, relatively good ability to learn new information, good visual-spatial skills, goodgeneral knowledge of the world.
• BUT – has lost all episodic memory. That is, he has no memory of his personal past, but can remember all factual information.
• TBI – loss of all pre-injury personal memories,but semantic memories intact
• Post injury, he could remember past memories , but devoid of emotion
• Questions: malingerer? If a real deficit, how to explain?
MYSTERY # 5 – CLINICAL FACTS
• More recent research indicated importance of right frontal lobe to a) retrieval; b) self-awareness and episodic memories
• Hypothesis: if right frontal lobe important to self-awareness and episodic memories, a focal lesion disconnecting RFL could theoretically result in a) lost of pre-injury episodic memories because could notretrieve; b) post-injury lost of “episodic” (warm, personal) nature of memories (Levine et al., Brain, 1998, 121)
BUT…a
+ 1 mm-4 mm-9 mm
b
47
10
45
10
47
1010
47
1111
IMPLICATIONS
• You need both anatomy and cognitive theory tounderstand the functions of the frontal lobes
• Experimental attempt to demonstrate focused attention deficit after TBI
• Moderate to severe TBI group compared to matched control group
• Procedure was developed to isolate the process of focused attention
• And – to show that effect was reliable, groups were tested twice, same time of day, one week apart
MYSTERY # 6 – TBI and FL Dysfunction
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3737
FEATURE INTEGRATION TEST
Test Target Distractors
Simple
Easy Choice
Complex Choice
Redundant Choice
none
blue bluered yellow
yellow red bluegreen37
Inconsistency in TBI
38
Stuss & Binns, 2008
Controls TBI
Inconsistency in Concussion
39
-15
-10
-5
0
5
10
15
20
25
30
Dif
fere
nce
(m
s)
Visit
Control
Concussed
1 2 3 4 5
Performance on correct trials in all three conditions of the
Multiple Choice Reaction Time Task over five visits
Stuss & Binns, 2008
LESSON
• Had to use my own frontal lobes to break my mental set from training as experimental psychologist which suggests that if resultsare not replicable, they are not valid; the results are “noise”
• Had to think as a clinician and listen to patients
• And one can show that variability itself is reliable in its own way
• But what causes variability? We postulated some “type” of frontal lobe control dysfunction
IMPLICATIONS
• The variability WAS THE DATA
• We use the terms “frontal functions” or “frontal dysfunction”
MYSTERY # 7 –FRONTAL LOBE ANATOMY
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• Look at the anatomy
BUT….
CENTRAL SULCUS CENTRAL
SULCUS
47 48
POLAR10Superior
Inferior 10
14INFERIOR MEDIAL
Ventromedial
Cingulate 24, 25
Paracingulate
SUPERIORMEDIAL
Superior Posteromedial 6a, 4
Superior Anteromedial 8b, 9
Cingulate 24
Ventrolateral 47/12, 45a, 45b, 44, 6b, 4
9, 46, 9/46d, 9/46v, 8b, 8ad, 8av, 6a, 4
Dorsolateral
LATERAL
SURFACE REGION
ORBITO-FRONTAL
14, 11, 13, 47/12
Paracingulate 32
32
CYTOARCHITECTURE
Stuss et al., 2002
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49
Summary of Lessons
• The reason that it is difficult to understandthe functions of the frontal lobes is that one has to consider many factors:
- functional/anatomical specificity- context of different types- the sophistication of cognitive theory- possible different types of control- the effect of disturbance in control onconsistency of performance
Examples of the “Mystery” of the Frontal lobes
Research findings that shed some light
The value of these findings to clinical application
Summary of the Lessons
OUTLINE
50
51
QUESTION
• If the frontal lobes have a dominant central organizing role, is this system unitary (an “executive”) or fragmented (a series of domain general control processes)?
• Frame within the role of the frontal lobes in “attention”
ContentionScheduling
(3)
TriggerDataBase
Special-purposeCognitiveSubsystems (1)
PerceptualSystem
SupervisoryAttentional System (4)
SchemaControl Units
(Action)
(2)
ANTERIOR ATTENTIONAL SYSTEMShallice (1991)
• Shallice, Alexander, Picton and myself
• Start with patients with focal lesions, to evaluate which brain regions are necessary for functions
• Differentiated “task” from “process”
• Differentiated “descriptive term” from “fundamental process”
• Scaffolded difficulty - why? – to demonstrate that frontal lobe patients could do simple tasks, and highlight at which level of difficulty problems arose
WE STARTED FROM SCRATCH
• We proposed five different frontal attentional processes, related to different frontal regions
• These processes are fundamental, in that they can explain performance on a series of differenttasks
- Energization- Inhibition- Contention Scheduling (setting of)- Monitoring- Logic – adjusting goals and energization based
on monitoring (setting the task)(Stuss et al., ANYAS, 1995, 769)
WITH THIS APPROACH
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5555
LET’S START WITH ATTENTION
• There are (at least) three separate processesrelated to attention within the frontal lobes, each related to a different frontal region
• Energization
• Task Setting
• Monitoring
55 5656
• TOP: Bar graph by coarse lesion localization:
RL – right lateral;
LL – left lateral;
SM – superior medial;
IM – inferior medial
• BOTTOM: Architectonic localization
STRUCTURE of DATA PRESENTATION
56
5757
• ENERGIZATION
– “The process of initiation and sustaining of any response made”
TELL THEM
57 58
ENERGIZATIONCONCENTRATE (ROBBIA)
Press Button
59
ENERGIZATIONCONCENTRATE (ROBBIA)
400
500
600
700
RT
(m
s)
LL RL IM SM CTL
Stuss et al., 2005; Stuss & Alexander, 2007 60
IMPLICATIONS
• Frontal processes are important even for simple
tasks – have to rethink idea of complexity
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IMAGING EVIDENCE of ENERGIZATION
Experimental Aim:
– to investigate the brain mechanisms and associated distinct processes related to the regulation of speed-accuracy strategy trial-by-trial by using fMRI.
62
METHOD:Speed/Accuracy Tradeoff
• Participants: 12 right-handed healthy subjects (6 F; mean age: 24 years, range: 19-37).
• Session: 6 runs (6 practice and 40 test trials per each run), preceded by two practice runs with feedback (on the 0 T scanner).
Targ
et-R
elat
ed
Brain Cluster
The Anterior Cingulate was mostly activated when it was necessary to
sustain a speeded response (no-switch SPD trials), consistently with a
role in energization (Paus, 2001; Stuss et al., 2005).Vallesi et al., 2012
RESULTS
6464
Anatomical Connectivity
FunctionalConnectivity
• Slower RT
• Inability to sustain task
Energization
65
TASK SETTING
– “The ability to establish a stimulus-response relationship”, requiring formation of a criterion to respond to a defined target with specific attributes, organization of the schemata to do a task, and adjustment of contention scheduling
66
TASK SETTING
• Can also be seen as a “sculpting” activity (Fletcher et al., 2000; Frith, 2000), where surface material to be carved represents a prepotent habitual response that needs to be overcome
• Emerging shape is the new strategy, or S-R association
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TASK SETTINGCONCENTRATE (ROBBIA)
0
0.5
1.0
1.5
2.0
# o
f F
als
e A
larm
s
LL RL IM SM CTL
Stuss et al., 2005; Stuss & Alexander, 2007
Test Target Distractors
Simple
Easy Choice
Complex Choice
Redundant Choice
none
blue bluered yellow
yellow red bluegreen68
FEATURE INTEGRATION TEST
69
TASK SETTINGCOMPLEX (FIT)
LL RL IM SM CTL
Fa
lse
Ala
rms
–F
als
e N
eg
ati
ve
s
0
2
4
6
10
8
70
TASK SETTINGIMAGING EVIDENCE
Experimental Aim:
– Speed-accuracy trade-off
71
-8
-6
-4
-2
0
2
4
6
8
10
ACC NS ACC SW SPD NS SPD SW
Be
ta V
alu
es
at
[-3
2 3
0 2
8]
Brain Cluster fMRI parameter estimate
Correlation with Accuracy
Cu
e-R
elat
ed
Correlation with Speed
r = .596, p<.05 r = -.64, p<.05r = -.64, p<.02
Vallesi et al., HBM, 2012.
SPEED-ACCURACY TRADE-OFFfMRI STUDY
7272
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
Executive Function
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73
MONITORING
– “The process of checking the task over time for ‘quality control’ and the adjustment of behaviour ”
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MONITORINGSIMPLE RT (ROBBIA)
• 5 different Inter-stimulus Intervals(ISI) (3,4,5,6, or 7 seconds), each occurring 10 times randomly
• Short ISI = 3 and 4 seconds
• Long ISI = 6 and 7 seconds
75
MONITORINGSIMPLE RT (ROBBIA)
-40
-30
-20
-10
0
10
20
ISIShort Long
ISI
Eff
ec
t
RL
Stuss et al., 2005; Stuss & Alexander, 2007
Test Target Distractors
Simple
Easy Choice
Complex Choice
Redundant Choice
none
blue bluered yellow
yellow red bluegreen76
FEATURE INTEGRATION TEST
77
MONITORINGCOMPLEX (FIT)
LL RL IM SM CTL
# o
f F
als
e N
eg
ati
ve
s
0
1
2
3
4
5
Stuss et al., 2005; Stuss & Alexander, 2007 78
or Foreperiod (FP)
*
Target Stimulus(0.3 sec)
Warning Stimulus
Task: choice RT (shape discrimination)
ITI(0.5-2.5 sec)
(2 sec)
Paradigm:
Fixed
Variable FP 1 sec
FP 3 sec
FP 1 secFP 3 sec
Baseline
MONITORING FOREPERIOD & fMRI
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Vallesi, McIntosh,Shallice & Stuss., J Cog Neurosc, 2009
Talairach coord. of right DLPFC: 52 40 26
r = .53, p < .05
8080
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
8181
LEFT LATERAL
Task Setting
RIGHT LATERAL
MonitoringEnergization
SUPERIOR MEDIAL 81 8282
THREE FRONTAL LOBE ATTENTIONAL CONTROL PROCESSES
• There are (at least) three separate processesrelated to attention within the frontal lobes, each related to a different frontal region
• Energization
• Task Setting
• Monitoring
8383
LET’S RETURN TO VARIABILITY
• Can the three separate processes related to attention within the frontal lobes, explain variability
• Examine response to errors within a task;
• The common response in a reaction time task is often to speed up over time, and thenwhen an error is made, slow down for the to trial to adapt to the situation and not makeanother error
83
Frontal Processes Underlying Variability
84
300
600
900
1200
Antecedent Error Subsequent
Mea
n R
eact
ion
Tim
e
Relationship in RT speed for trials antecedent and subsequent to an error
Stuss et. al., 2003
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85
Observations on Variability
• Individual variability can be caused by impairment in different control processes
• These different control processes are revealed by examining performance under a specific context – reaction to making an error
• The observation, the measurement of variability, is not the process; one has to unveil the process to develop focused rehabilitation
8686
FROM ATTENTION TO EMOTIONS AND META-COGNITION
• Let’s look at possible other functions associated with the frontal lobes
- Behavioural/emotional self-regulation
- Meta-cognition/integration
86
8787
BEHAVIOURAL/EMOTIONALSELF-REGULATION
• Emotional Processing:
♦ Difficulty in understanding the emotionalconsequences of behaviour
• Behavioural Self-Regulation:
♦ Required in situations where cognitive analysis, habit, or environmental cues are not sufficient to determine the most adaptive response
87 8888
Knower SubjectBasic Paradigm
?
BEHAVIOURAL/EMOTIONALSELF-REGULATION
Deception Task
88
8989
BF RNF LNF
Per
cen
t p
er G
rou
p (
SD
>2)
RF LF
80-
0
10-
20-30-
40-50-60-70-
ImpairedNon-Impaired
DECEPTION TASK
89 9090
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
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9191
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
9292
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
DorsolateralCircuit9, 46
9393
Lateral/MedialOrbitofrontal
Circuit11,12,13,14
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
DorsolateralCircuit9, 46
9494
Lateral/MedialOrbitofrontal
Circuit11,12,13,14
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
DorsolateralCircuit9, 46
Caudate
GlobusPallidus
Thalamus
MotorCircuit
Oculo-motorCircuit
5 circuits - Figure Motor CircuitDorsolateral
prefrontal-subcortical circuit
Oculomotor Circuit
SuperiorMedialCircuit
Lateral/MedialOrbitofrontal
Circuit
Origin:9, 46
Origin:AC & SM
Origin:Lateral & orbital 12
Origin:8
Origin:Motor Cortex
Executive Function
Affect & Social Behaviour
Executive Function
Motivational Function
Executive Function
Behavioural Effects: What the literature says
Behavioural &Emotional
Self-Regulation
Energization Executive Function
Behavioural Effects: What we say
Caudate
Globus Pallidus
Thalamus
9696
METACOGNITIVE PROCESSES
• A reflective representation of one’s own mental states, beliefs, attitudes and experiences
• Affects ability to make inferences about the world, to empathize with and understand the actions of others, and to serve as a base forappropriate social judgments
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9797
• Paris Hotel-“Leave your values at the front desk”
• Bangkok Cleaners-“Drop you trousers here for best results”
• Hong Kong Dentist-“Teeth extracted by the latest Methodists”
METACOGNITIVE PROCESSES
Humour Study – Is this funny?
Shammi & Stuss, 1999
97
• In a Rhodes tailor shop-“Order your summers suit. Because is big rush we
will execute customers in strict rotation.”
• In a restaurant in Paris-“Lunch will be served to patrons between noon
and 3 p.m.”
• In a Bangkok temple-“It is forbidden to enter a woman even a foreigner
if dressed as a man.”
9999
METACOGNITIVE PROCESSES
Difference Between Rating of Humourous and Neutral Items
99 100100
Lateral/MedialOrbitofrontal
Circuit11,12,13,14
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
DorsolateralCircuit9, 46
Caudate
GlobusPallidus
Thalamus
MotorCircuit
Oculo-motorCircuit
Metacognition
• Integration and coordination ofmotivational, emotional, executivecapacities
101101
Lateral/MedialOrbitofrontal
Circuit11,12,13,14
Anatomical Connectivity
FunctionalConnectivity
• Initial Errors
• False Alarms
Left: Task Setting
• Slower RT
• Inability to sustain task
Energization
• Within/Between task variability
• Errors of all types (sensitivity)
• Impaired variable foreperiod effect
• Inability to maintain count
Right: Monitoring
Executive Function
• Normal executive
• Decreased awareness of deception
• Impaired reward/riskprocessing
Behavioural/Emotional
Self-Regulation
Superior MedialCircuit
9, 24, 32
DorsolateralCircuit9, 46
Caudate
GlobusPallidus
Thalamus
MotorCircuit
Oculo-motorCircuit
Metacognition
• Integration and coordination ofmotivational, emotional, executivecapacities
LATERAL PARIETAL&
TEMPORAL POLE
ROSTRAL‐STGMID‐STGINSULA
AMYGDALAROSTRAL
PREFRONTALCORTEX
10
102102
PROPOSAL – THERE ARE FOURCATEGORIES OF FL DYSFUNCTION
• The four categories of frontal functions map onto general anatomical localization based onprinciples of anatomical development andconnectivity
♦ Energization: Superior medial frontal
♦ Executive: Lateral prefrontal cortex
♦ Behaviour/Emotional Self-Regulation: Ventralmedial prefrontal cortex
♦ Metacognition (Theory of Mind): polar(Stuss, JINS, 2011) 102
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ASSESSMENT: FOUR DOMAINS
A. Energization/regulation: superior medial
B. Executive/cognitive: lateral
C. Metacognitive: frontal poles, primarily right
A. Behavioural Self-regulatory: orbital/ventromedial
Frontal Pole
Ventromedial
Ventrolateral
SMA
Ventromedial
Frontal Pole
Anterior Cingulate
SuperiorMedial
Supplementary Motor Area (SMA)
Premotor Area
Primary Motor Area
Frontal Pole
Ventrolateral
Dorsolateral
THIS CATEGORIZATION is COMPATIBLE with ANATOMY and
CONNECTIVITY
• Two major divisions are based on evolution of cortical architectonics (e.g.,Sanides; Pandya; Stuss & Levine, 2002)
– Dorsolateral: from hippocampal, archicortical trend• Spatial and conceptual reasoning: executive cognitive
– Ventral(medial): from olfactory, paleocortical trend• Emotional processing: behavioural self-regulatory
• Network connectivity (Alexander et al., 1986) – adds action regulation (e.g., energization)
• Metacognitive – role of area 10 in frontal interconnectivity
CONCLUSIONS
“The frontal lobes do not equal a central executive. Executive functions represent only one functional category within the frontal lobes. These frontalfunctions are domain general, possibly because ofthe extensive reciprocal connections with virtually all other brain regions, integrating information fromthese regions. Further integration of these processeswith emotional and motivational processes allows the most complex behaviors.”
Stuss (2011). JINS, p.763
IMPLICATION
• The frontal lobes are not a monolith. There are at least four functional categories within the frontal lobes.
• There are likely subdivisions within the categories; e.g., different types of monitoring (Petrides, in Stuss & Knight, 2012); potential hierarchies of “task setting” (D’Esposito); fractionation of area 10 (Burgess, in Stuss & Knight, 2012).
Examples of the “Mystery” of the Frontal lobes
Research findings that shed some light
The value of these findings to clinical application
Summary of the Lessons
OUTLINE
108
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WHY IS FRACTIONATION RELEVANT?
• This is the era of neural networks, inter-connectivity, system analysis –- fractionation is so old school
• ANSWER: I can work on rehabilitation andtreatment of separate processes, the outcome of which I can measure on its effect on the system network – but I don’tknow how to rehab a system without understanding its component parts
110
APPLICATION OF FRAMEWORK TO COGNITIVE
NEUROREHABILITATION• For reviews and elaboration of concepts, see
- Cicerone et al., 2006- Levine, Turner & Stuss, 2008 - Stuss, 2008- Stuss, 2011
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111
• Externally cuing initiation (Sohlberg et al., 1988)
• Pharmacological dopamine agonist (Powell et al., 1996)
REHABILITATION of FUNCTION
Task Setting
• Simplification of complex problems (Von Cramon et al, 1991)
• Cueing and feedback (Fox et al., 1989)
Executive Functions
• Goal Management Training (Levine et al, 2000, 2007)
Energization
Behavioural/Emotional Self‐Regulation
• Prompts/rewards – Monitoring – Control (Alderman et al, 1995)
Meta‐cognitive Processes
• Problem solving and role play (Ownsworth et al, 2000)
• Modifying people’s predictions, not behaviour (Rebmann & Hannon et al, 1995)(Youngjohn & Altman, 1989)
The Stuss Frontal Lobe Model Is Useful For Rehabilitation Purposes
• The 3 clients showed dissociable patterns broadly seen on all measures
• The Activation and Executive Cognition domains showed clear relative relationships in all cases
• Structured behavioural observations were easy, highly useful, and directed rehab planning
Examples of the “Mystery” of the Frontal lobes
Research findings that shed some light
The value of these findings to clinical application
Summary of the Lessons
OUTLINE
113
I AM STILL LEARNING!
AND I HAVE LEARNED MOST WHEN I HAVE OPENED
MYSELF UP TO PATIENTS AND WHAT THEY “TELL”
ME
LESSONS
114
11/6/2015
20
THANK YOU