Prefrontal tDCS modulates behavioural and neural signatures associated with consciousness.
Aude Sangare, Esteban Munoz-Musat, Bertrand Hermann, Caroline Herault, Laouen Belloli, Manon Breton, Alaina Borden, Amina Ben Salah, Melanie Valente, Sophie Demeret, Benjamin Rohaut, Jacobo Sitt, Lionel Naccache
Neuroimage May 22, 2026 DOI: 10.1016/j.neuroimage.2026.122015 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Double-blind, sham-controlled crossover trial Peer reviewed |
|---|---|
| Sample size | 20 |
| Population | Severely brain-injured patients with disorders of consciousness (12 minimally conscious state, 7 vegetative state/unresponsive wakefulness syndrome, 1 emergence from minimally conscious state) |
| Intervention | Transcranial direct current stimulation (tDCS) |
| Dose | 2 mA for 20 min |
| Duration | 20-minute stimulation sessions; follow-up at 6 weeks and 6 months |
| Measures | Coma Recovery Scale-Revised (CRS-R), event-related potentials using the local-global paradigm, resting EEG |
| Keywords | Humans Consciousness disorders Electroencephalography Cross-over studies Double-blind method Evoked potentials Adult Middle aged Female Dorsolateral prefrontal cortex Electrophysiology Neuromodulation Disorders of consciousness |
| Key findings | Anodal tDCS over the left dorsolateral prefrontal cortex produced a significant group-level improvement in Coma Recovery Scale-Revised scores, with 9 of 20 patients (45%) responding and 5 (25%) showing new behavioural items absent with sham. However, no patient transitioned to a different consciousness state and no improvement persisted at 6 weeks or 6 months. EEG complexity, gamma power, and delta connectivity increased after tDCS, while event-related potentials and multivariate EEG prediction of conscious state showed no significant modulation. |
Abstract
Introduction: Transcranial direct current stimulation (tDCS) has shown encouraging results in patients with Disorders of Consciousness (DoC), yet its efficacy and mechanisms remain unclear. This study aimed to evaluate the effects of left dorsolateral prefrontal cortex (DLPFC) tDCS on Coma Recovery Scale-Revised (CRS-R) scores and EEG activity in severely brain-injured DoC patients.
Methods: In a double-blind, sham-controlled crossover design, 2 mA anodal and sham tDCS were randomly administered over the left DLPFC (right orbito-frontal cathode) for 20 min. CRS-R scores, event-related potentials using the local-global paradigm and resting EEG were recorded before and after each stimulation. Follow-up assessments occurred at 6 weeks and 6 months.
Results: Between November 2018 and April 2022, 20 patients were included (12 in a Minimally Conscious State (MCS), 7 in a Vegetative State/Unresponsive Wakefulness Syndrome (VS/UWS), and one patient who emerged from MCS (emergence from MCS (eMCS)). Group-level analysis across all patients revealed a significant treatment effect on CRS-R scores (p = 0.02). Nine patients (45%; 6 MCS, 3 VS/UWS) responded to tDCS, with five (25%; 3 MCS, 2 VS/UWS) exhibiting new behavioural items absent in pre- and post-sham evaluations. However, no patient demonstrated a change in consciousness state (e.g., transition from VS/UWS to MCS), nor was any improvement observed at 6-week or 6-month. EEG analysis showed increased complexity, gamma-band power, and delta-band cortico-cortical functional connectivity post-tDCS. Multivariate EEG analyses did not show a significant effect of tDCS on the prediction of conscious state, and ERP assessments using the local-global paradigm revealed no modulation of novelty detection responses following stimulation. Simulation analyses on individual brain anatomical structures revealed that responders displayed stronger tDCS-induced electric fields within a Fronto-parietal network than non-responders.
Conclusion: Despite the limited sample size, our results provide additional evidence in favour of the behavioural and electrophysiological effects of tDCS in DoC patients.
Citations in the library
Cites 3
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