Sub-study of the NEURODOC Project : Neurophysiological Evaluation of a Routine Care Open Label tDCS Session
Condition: Disorder of Consciousness; Traumatic Brain Injury; Anoxic Brain Injury; Stroke
MeSH terms: Brain Injuries; Brain Injuries, Traumatic; Consciousness Disorders; Wounds and Injuries
Study type: Interventional

Summary: 
      Limited treatments are available to improve consciousness in severely brain injured patients.
      Transcranial Direct Current stimulation (tDCS) is one of the few therapeutics that showed
      evidence of efficacy to increase level of consciousness and functional communication in some
      Minimally Conscious State (MCS) patients, and in some Vegetative State (VS) patients.

      However the mechanisms by which tDCS improves consciousness are poorly understood and the
      electrophysiological effects of such a stimulation have never been studied in disorders of
      consciousness patients.

      In this study, the investigators will use detailed clinical examinations and
      electrophysiological assessments (quantitative high-density EEG and event-related potentials)
      to assess the effect of a open-label single session of left dorsolateral prefrontal cortex
      tDCS stimulation administered as routine care.
    

Detailed description: 
      Limited treatments are available to improve consciousness in severely brain injured patients.
      Transcranial Direct Current stimulation (tDCS) is one of the few therapeutics that showed
      evidence of efficacy to increase level of consciousness and functional communication in some
      Minimally Conscious State (MCS) patients, and in some Vegetative State (VS) patients (1, 2,
      3, 4), with no side effects reported.

      However the mechanisms by which tDCS improves consciousness are poorly understood and the
      electrophysiological effects of the stimulation have never been studied in disorders of
      consciousness patients.

      In this study, the investigators will use detailed clinical examinations (Coma Recovery Scale
      - Revised (5)) and electrophysiological assessments (quantitative high-density EEG and
      event-related potentials) (6, 7) and event-related potentials (8, 9) together with a standard
      morphological MRI to assess the effect of a open-label single session of left dorsolateral
      prefrontal cortex tDCS stimulation administered as routine care.

      The primary goal is to investigate electrophysiological response to tDCS and its relation to
      behavioral response to better understand how tDCS affects consciousness in disorders of
      consciousness patients.

      References:

        1. Angelakis, E. et al. Transcranial Direct Current Stimulation Effects in Disorders of
           Consciousness. Arch. Phys. Med. Rehabil. 95, 283-289 (2014).

        2. Thibaut, A., Bruno, M.-A., Ledoux, D., Demertzi, A. & Laureys, S. tDCS in patients with
           disorders of consciousness: sham-controlled randomized double-blind study. Neurology 82,
           1112-1118 (2014).

        3. Thibaut, A. et al. Controlled clinical trial of repeated prefrontal tDCS in patients
           with chronic minimally conscious state. Brain Inj. 1-9 (2017).
           doi:10.1080/02699052.2016.1274776

        4. Martens, G. et al. Randomized controlled trial of home-based 4-week tDCS in chronic
           minimally conscious state. Brain Stimulat. (2018). doi:10.1016/j.brs.2018.04.021

        5. Giacino, J. T. & Kalmar, K. Diagnostic and prognostic guidelines for the vegetative and
           minimally conscious states. Neuropsychol. Rehabil. 15, 166-174 (2005).

        6. Sitt, J. D. et al. Large scale screening of neural signatures of consciousness in
           patients in a vegetative or minimally conscious state. Brain 137, 2258-2270 (2014).

        7. Engemann, D. A. et al. Robust EEG-based cross-site and cross-protocol classification of
           states of consciousness. Brain J. Neurol. 141, 3179-3192 (2018).

        8. Bekinschtein, T. A. et al. Neural signature of the conscious processing of auditory
           regularities. Proc. Natl. Acad. Sci. 106, 1672-1677 (2009).

        9. Faugeras, F. et al. Event related potentials elicited by violations of auditory
           regularities in patients with impaired consciousness. Neuropsychologia 50, 403-418
           (2012).
    

Intervention name(s): Coma Recovery Scale - revised; Electrophysiological recordings
Intervention type(s): Behavioral; Diagnostic Test
Intervention description(s): Assessment of the level of consciousness by the dedicated Coma Recovery Scale - Revised, current gold-standard in consciousness level assessment.
Assessment before and after the tDCS session (immediately before and after the electrophysiological assessment, see below).; The electrophysiological assessment consisted of:
a 5 minutes resting state high-density EEG recording
a approximately 6 minutes auditory oddball paradigm These two procedures were administered immediately before and after the tDCS session
Other intervention name(s): CRS-R; EEG
Intervention model: Single Group Assignment
Intervention model description: Electrophysiological evaluation of a routine care intervention: single session of left dorso-lateral transcranial direct current stimulation
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Disorders of consciousness; Transcranial direct current stimulation; Electroencephalography; Electrophysiological signatures of consciousness; Coma Recovery Scale - Revised