Effects of sham-controlled double blind transcranial direct current - - PowerPoint PPT Presentation

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Effects of sham-controlled double blind transcranial direct current - - PowerPoint PPT Presentation

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Effects of sham-controlled double blind transcranial direct current stimulation in patients with disorders of consciousness XXth World Congress of Neurology Marrakesh, Morocco 16 November 2011 THIBAUT Aurore PhD candidate Coma Science Group

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Effects of sham-controlled double blind transcranial direct current stimulation in patients with disorders of consciousness

XXth World Congress of Neurology Marrakesh, Morocco 16 November 2011

THIBAUT Aurore PhD candidate

Coma Science Group Cyclotron Research Centre & Neurology Dept & University Hospital of Liège Belgium

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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | methods, ethics & quality of life | perspectives

Laureys, Owen and Schiff Lancet Neurology, 2005 Laureys et al, BMC Medicine 2010 Demertzi et al, Exp Rev Neurother, 2008

Patients

NORMAL CONSCIOUSNESS

AROUSAL AWARENESS

COMA

AROUSAL AWARENESS

VEGETATIVE STATE/ UNRESPONSIVE WAKEFULNESS SYNDROME

AROUSAL AWARENESS

MINIMALLY CONSCIOUS STATE

AROUSAL AWARENESS

Introduction | Materials and Methods | Results │Discussion

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Why direct current stimulation?

Introduction | Materials and Methods | Results │Discussion

Stimulation Population Effects Authors Prefrontal cortex Healthy subjects Memory

Marshall et al, J Neurosci 2004

Alzheimer’s patients Memory

Ferrucci et al, Neurology 2008

Stroke patients Attention

Jo et al, Am J Phys Med Rehabil 2009

Aphasic patients Language

Baker et al, Stroke 2010

  • Non-invasive
  • Easy to apply
  • Cheap equipment
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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | methods, ethics & quality of life | perspectives

AIM of the study

Introduction | Materials and Methods | Results │Discussion

To assess tDCS effects on cognition in patients with disorders of consciousness

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Methods

  • Design: sham-controlled double blind
  • 4 CRS-R: pre-post tDCS/pre-post sham
  • Patients
  • 55 patients (16 women; aged 43 ± 18 y)
  • 25 VS/UWS, 30 MCS
  • 25 traumatic / 30 non-traumatic
  • Outcome measure
  • Coma Recovery Scale-Revised (CRS-R, Giacino 2004)
  • Hypothesis: tDCS responders:
  • CRS-R total tDCS > pre-tDCS, sham, pre-sham
  • Statistical analysis: ANOVA (Stata)

Introduction | Materials and Methods | Results │Discussion

DC Stimulator Plus

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Group data (n=55)

Introduction | Materials and Methods | Results | Discussion |

** p<.001 * p <.05

Interactions

  • MCS>VS, p=0.026
  • Acute> chronic, p=0.004
  • Etiology, p=0.37

pre tDCS post tDCS pre sham post sham

** *

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 1 2 CRS-R scores

VS/UWS vs. MCS

Introduction | Materials and Methods | Results | Discussion |

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 1 2 CRS-R scores pre tDCS post tDCS pre tDCS post tDCS

VS/UWS MCS

*

Trauma Non trauma Chronic Acute

17 responders

  • 15 MCS (7 acute,8 chronic)
  • 2 VS/UWS (acute)
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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | methods, ethics & quality of life | perspectives

Conclusions

  • Deep Brain Stimulation (Schiff et al., Nature 2008)
  • Amantadine (Schnakers, 2008)
  • Non-invasive non-pharmacological class A evidence for

tDCS induced cognitive improvement in MCS

Introduction | Materials and Methods | Results | Consclusions

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THANK YOU

Questions to: athibaut@chu.ulg.ac.be

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Responders

25 VS/UWS 2 responders 2/11 VS/UWS acute 0/14 VS/UWS chronic 30 MCS 15 responders 7/9 acute 8/21 chronic

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Responders: audition subscale

pre tDCS post tDCS pre sham post sham

Consistent movement to command Reproducible movement to command Localisation of sounds Auditory startle None

* *

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Responders: subscales - visual

pre tDCS post tDCS pre sham post sham

Object recognition Reaching Visual pursuit Fixation Visual startle None

* *

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tDCS parameters and safety

Intensity: 2mA Time: 20 minutes Voltage: max 26V Electrodes: 35cm² Max: 0.1mA/cm²

U=R*I

2mA et 10kOhm = 20V OK 2mA and 20kOhm = 40V STOP

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tDCS presumed mode of action

Direct effects

Modification of neuronal excitability

Long term effects

Modification of ion channels (Na+, Ca2+) Modification of NMDA receptors efficacy Modification of inter-neurons still hypothesis

Nitsche et al., J Physiol 2000 Nitsche et al., Neuroscientist 2010

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tDCS critisisms

  • Short term effect
  • Moderate clinical change
  • Unknown physiological effects (cathode)
  • Improve electrode position?

Limitations: