Prefontal tDCS in Patients With Disorders of Consciousness: Neurophysiological and Behavioural Outcomes
Condition: Vegetative State; Minimally Conscious State; Disorder of Consciousness
MeSH terms: Consciousness Disorders; Persistent Vegetative State
Study type: Interventional

Summary: 
      Non-invasive brain stimulations techniques have recently shown promising results in patients
      with disorders. Notably, transcranial direct current stimulation (tDCS) applied over the left
      dorsolateral prefrontal cortex has proved to be effective in improving signs of consciousness
      in about 50% of patients in MCS either after a single stimulation or after repeated sessions.
      However, brain mechanisms underlying tDCS effects remain poorly understood. Here we aim to
      assess the effects of prefrontal tDCS on neurophysiological (i.e., electroencephalography -
      EEG - primary outcome) and behavioral (secondary outcome) measures in severely brain-injured
      patients with DOC.
    

Detailed description: 
      Currently, therapeutic options for severely brain-injured patients with disorders of
      consciousness (DOC), including patients in unresponsive wakefulness syndrome (UWS) and
      minimally conscious state (MCS), are limited and still need to be improved to influence
      long-term outcomes. Non-invasive brain stimulations (NIBS) techniques have recently shown
      promising results in DOC. Notably, transcranial direct current stimulation (tDCS) applied
      over the left dorsolateral prefrontal cortex has proved to be effective in improving signs of
      consciousness in about 50% of patients in MCS either after a single stimulation or after
      repeated sessions. However, brain mechanisms underlying tDCS effects remain poorly
      understood.In the present protocol, the investigators will assess the effects of prefrontal
      tDCS on neurophysiological (i.e., electroencephalography - EEG - primary outcome) and
      behavioral (secondary outcome) measures in severely brain-injured patients with DOC in a
      double-blind sham-controlled design. One anodal and one sham tDCS will be delivered in a
      randomized order in chronic (>28 days post-onset) severely brain-damaged patients. The
      stimulation will have an intensity of 2 mA and will last 20 minutes. The anode will be placed
      on the left dorsolateral prefrontal cortex and the cathode on the right supraorbital region.
      Ten minutes of high-density EEG will be recorded using a 256-channel saline electrode net
      (Electrical Geodesics) directly before and after each tDCS session. Behavioral assessments
      will be performed using the Coma Recovery Scale-Revised before and after each session by an
      investigator blinded to the treatment allocation.
    

Intervention name(s): anodal tDCS; sham tDCS
Intervention type(s): Device; Device
Intervention description(s): Patients will receive anodal tDCS during 20 minutes preceded and followed by a behavioral assessment (Coma Recovery Scale Revised) and a high density EEG. The anode will be placed over F3 in order to stimulate the left dorsolateral prefrontal cortex and the cathode over the right supraorbital area.; Identical to anodal tDCS, except that the stimulation will be stopped after 15 seconds.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Vegetative state; Minimally Conscious State; Disorders of consciousness; Transcranial direct current stimulation; Non invasive brain stimulation; Neuromodulation; High density electroencephalography