Transcranial Direct Current Stimulation in Patients With Disorders of Consciousness (tDCS in DOC)

Transcranial Direct Current Stimulation in Patients With Disorders of Consciousness: a Sham-controlled Randomised Double Blind Study

Previous studies showed that anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal (DLPF) cortex transiently improves performance of memory and attention. Investigator assessed the effects of left DLPF-tDCS on Coma Recovery Scale-Revised (CRS-R) scores in severely brain damaged patients with disorders of consciousness in a double-blind sham-controlled experimental design.

Following severe brain damage and coma, some patients may remain in a vegetative state (VS) or minimally conscious state (MCS). At present, there are no evidence-based guidelines regarding the treatment of patients with disorders of consciousness (DOC). Investigator aim to assess the effect of single session anodal (i.e., excitatory) transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPF) on the level of consciousness in DOC patients in a double blind randomized sham controlled study. tDCS is a form of safe non-invasive cortical stimulation, modulating cortical excitability at stimulation sites via weak polarizing currents, previously reported to transiently improve working memory and attention by stimulating the left DLPF in healthy subjects and patients with stroke, Parkinson's or Alzheimer's disease.

vegetative state, minimally conscious state, disorders of consciousness, transcranial direct current stimulation

Patients received anodal tDCS (on DLPF cortex) during 20 minutes preceded and followed by a clinical assessment (Coma Recovery Scale-Revised)

Patient received a sham tDCS (5sec of stimulation). The device runs during 20minutes and the anode was placed over the DLPF cortex. A behavioral assessment preceded and followed the stimulation.

patients received anodal tDCS (on PFDL cortex) during 20 minutes preceded and followed by a behavioral assessment (Coma Recovery Scale Revised)

Patient received a sham tDCS (5sec of stimulation). The device runs during 20minutes and the anode was placed over the DLPF cortex. A behavioral assessment preceded and followed the stimulation.

At the group level, assess the modification of CRS-R total scores in anodal tDCS as compared to sham stimulation in VS/UWS and MCS populations The Coma Recovery Scale Revised (CRS-R) is a behavioral scale performed at the patient's bedside. It consists of 23 hierarchically arranged items that comprise 6 subscales addressing auditory, visual, motor, verbal, communication, and arousal functions. Scoring is based on the presence or absence of specific behavioral responses to sensory stimuli administered in a standardized manner. Maximum scores of each subscale are summed to obtain the total score (from 0 to 23). The lowest item on each subscale represents reflexive activity, whereas the highest items represent cognitively mediated behaviors.

Inclusion Criteria: post-comatose patients patients in vegetative/unresponsive or minimally conscious state patients with stable cardiorespiratory parameters patients free of sedative drugs and Na+ or Ca++ channel blockers (e.g., carbamazepine) or NMDA receptor antagonists (e.g., dextromethorphan) Exclusion Criteria: premorbit neurology antecedent patients in coma or <1week after the acute brain insult patients with a metallic cerebral implant or a pacemaker (in line with the safety criteria for tDCS in humans)

Multi-Society Task Force on PVS. Medical aspects of the persistent vegetative state (1). N Engl J Med. 1994 May 26;330(21):1499-508. doi: 10.1056/NEJM199405263302107.

Giacino JT, Ashwal S, Childs N, Cranford R, Jennett B, Katz DI, Kelly JP, Rosenberg JH, Whyte J, Zafonte RD, Zasler ND. The minimally conscious state: definition and diagnostic criteria. Neurology. 2002 Feb 12;58(3):349-53. doi: 10.1212/wnl.58.3.349.

Nitsche MA, Fricke K, Henschke U, Schlitterlau A, Liebetanz D, Lang N, Henning S, Tergau F, Paulus W. Pharmacological modulation of cortical excitability shifts induced by transcranial direct current stimulation in humans. J Physiol. 2003 Nov 15;553(Pt 1):293-301. doi: 10.1113/jphysiol.2003.049916. Epub 2003 Aug 29.

Nitsche MA, Liebetanz D, Lang N, Antal A, Tergau F, Paulus W. Safety criteria for transcranial direct current stimulation (tDCS) in humans. Clin Neurophysiol. 2003 Nov;114(11):2220-2; author reply 2222-3. doi: 10.1016/s1388-2457(03)00235-9. No abstract available.

Fregni F, Boggio PS, Nitsche M, Bermpohl F, Antal A, Feredoes E, Marcolin MA, Rigonatti SP, Silva MT, Paulus W, Pascual-Leone A. Anodal transcranial direct current stimulation of prefrontal cortex enhances working memory. Exp Brain Res. 2005 Sep;166(1):23-30. doi: 10.1007/s00221-005-2334-6. Epub 2005 Jul 6.

Kang EK, Kim DY, Paik NJ. Transcranial direct current stimulation of the left prefrontal cortex improves attention in patients with traumatic brain injury: a pilot study. J Rehabil Med. 2012 Apr;44(4):346-50. doi: 10.2340/16501977-0947.

Boggio PS, Ferrucci R, Rigonatti SP, Covre P, Nitsche M, Pascual-Leone A, Fregni F. Effects of transcranial direct current stimulation on working memory in patients with Parkinson's disease. J Neurol Sci. 2006 Nov 1;249(1):31-8. doi: 10.1016/j.jns.2006.05.062. Epub 2006 Jul 14.

Ferrucci R, Mameli F, Guidi I, Mrakic-Sposta S, Vergari M, Marceglia S, Cogiamanian F, Barbieri S, Scarpini E, Priori A. Transcranial direct current stimulation improves recognition memory in Alzheimer disease. Neurology. 2008 Aug 12;71(7):493-8. doi: 10.1212/01.wnl.0000317060.43722.a3. Epub 2008 Jun 4.