The neurology of consciousness: what can we learn from the vegetative state ? Steven Laureys
Coma Science Group Cyclotron Research Centre & Neurology Dept. University of Liège, Belgium
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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Overview
Disorders of consciousness Behavioural evaluation Electrophysiology Neuroimaging Ethics & quality of life Terry Schiavo °1963, vegetative 1990, † 2005
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Mind brain beliefs
Zeman 2005 in The Boundaries of Consciousness (Ed) Laureys
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Consciousness Conscious Wakefulness Lucid Dreaming
Locked-in syndrome Drowsiness
REM Sleep
Deep Sleep
Light sleep
Minimally Conscious State
General Anesthesia Coma
Laureys, Trends in Cognitive Sciences, 2005
Vegetative state
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Disorders of consciousness
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Clinical entities
Permanent Minimally Conscious State
Laureys, Scientific American, 2007
?
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Clinical evaluation
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Motor activity in brain death residual spinal activity: • finger jerks • undulating toe flexion sign • triple flexion response • Lazarus sign • pronation-extension reflex • facial myokymia
Lazarus' sign in brain death Bueri et al Mov Disord. 2000, 15:583-6
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Blink and you live
Laureys et al., Progress in Brain Research, 2005
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Electrophysiology
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Bispectral index
Bispectral index
EEG-BIS in coma
coma VS MCS recovery
Coma Recovery Score
Schnakers, Majerus and Laureys, Neuropsychological Rehabilitation, 2005
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Cognitive evoked potentials
minimally conscious state
µV -10.0
OTHER NAMES
-7.5 -5.0
OWN NAME
N1
-2.5 0.0 100
200
300
400
500
600
700
800
900
1000 1100
1200 1300 1400 1500 ms
2.5 5.0 7.5 10.0
Laureys, Perrin et al., Neurology, 2004
P3
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
P300 to given name n=5
n=4
n=6
n=5
Perrin et al, Archives in Neurology, 2006
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Neuroimaging
c resting brain function d brain activation studies passive paradigms z active paradigms z
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Neuroimaging
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Resting metabolism
Laureys, Owen & Schiff, Lancet Neurology, 2004 (sleep data from Pierre Maquet; anesthesia data from Mike Alkire)
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Global metabolism
Laureys, Maquet, Moonen, Encyclopedia of Neuroscience, 2007
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Regional changes
n=60 Laureys et al, New Encyclopedia of Neuroscience (Ed.) Larry Squire, in press
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
“default” resting state
Raichle & Snyder Neuroimage, in press
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
default activity predicts perception
3 seconds before simulation: • default lateral fronto-parietal activity is high ⇒ stimuli will be perceived • default medial parietal activity is high ⇒ stimuli will be missed
Boly et al, PNAS, Epub ahead of print
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Functional connectivity
Laureys et al., Lancet, 2000
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Thalamic stimulation
Schiff et al., Nature, 2007
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Pharmacological stimulation amantadine
Schnakers et al, JNNP in press
amantadine
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Neuroimaging
c resting brain function d brain activation studies passive paradigms z active paradigms z
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Vegetative is not brain dead
Laureys, Nature Reviews Neuroscience, 2006
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Cortical activation (n=15)
(n=15)
Laureys et al., Neuroimage, 2002
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Disconnected S1
Laureys et al., Neuroimage, 2002
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Abla con Ella
"…a (wo)men’s brain is a mystery... and even more so in this state."
Pedro Almodóvar
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Do they hear anything?
Laureys et al., Brain, 2000 Boly et al, Archives of Neurology, 2004
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Emotional processing
Laureys et al., Neurology, 2004
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Neuroimaging
c resting brain function d brain activation studies passive paradigms z active paradigms z
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
NAVIGATION
TENNIS
When thoughts become action
Boly et al, NeuroImage 36 (2007) 979-92
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Passive paradigms
Owen, Coleman, Boly, Davis, Laureys and Pickard, Science, 2006
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Active paradigms
Owen, Coleman, Boly, Davis, Laureys and Pickard, Science, 2006
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
fMRI precedes the clinic vegetative
Di et al, Neurology, 2007
minimally conscious
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Ethics & quality of life
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Locked-in syndrome (LIS)
Laureys et al., Progress in Brain Research, 2005
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Quality of life in LIS
Short Form-36 n=17 duration 6±4 y
Laureys et al., Progress in Brain Research, 2005
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Conclusions
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disorders of consciousness | clinicalevaluation evaluation | electrophysiology | neuroimaging | ethics & quality of of lifelife | conclusion disorders of consciousness | behavioural | electrophysiology | neuroimaging | methods, ethics & quality | perspectives
Not all “coma”
Laureys, Owen and Schiff, Lancet Neurology, 2005
AWARENESS
LOCKED-IN SYNDROME
AROUSAL
MINIMALLY CONSCIOUS STATE
AWARENESS
AWARENESS
AROUSAL
AWARENESS
VEGETATIVE STATE
AROUSAL
COMA
AROUSAL
AWARENESS
AROUSAL
NORMAL CONSCIOUSNESS
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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
Take home
• Need for objective markers of consciousness in comatose states • Vegetative state : disconnection syndrome with dysfunction of fronto-parietal network of “higher order” cortices (default network) • Minimally conscious state : intact pain & emotional perception • Locked-in syndrome : unexpected self-scored quality of life • Much more research is needed
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disorders of consciousness | clinical evaluation | electrophysiology | neuroimaging | ethics & quality of life | conclusion
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