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Updated: Jun 19, 2026
Simultaneous EEG Monitoring During Transcranial Direct Current Stimulation
Published on: June 17, 2013
Single-channel EEG captures tDCS-induced changes in neural reactivity: a pilot study in disorders of consciousness
Lior Molcho1, Neta B Maimon1,2, Nathan Intrator1,3,4
1Neurosteer Inc, New York City, NY, USA.
Background:
Understanding and enhancing neural recovery in disorders of consciousness (DoC) remains a critical challenge in clinical care. Clinical scales such as the Coma Recovery Scale-Revised (CRS-R) are essential, but reflect behavioral responsiveness and may not fully capture subtle neurophysiological changes. Transcranial direct current stimulation (tDCS) has shown promise, yet objective biomarkers to assess treatment response are needed.
Objectives:
This proof-of-concept study explores the feasibility and sensitivity of combining a compact single-channel EEG with noninvasive brain stimulation to assess changes in neural reactivity in individuals with DoC.
Design:
Pilot observational study with DoC patients undergoing intervention; healthy controls were assessed to provide a physiological reference benchmark for interpreting mismatch negativity (MMN) responses and assess the specificity of EEG biomarkers relative to DoC patients.
Methods:
Six DoC patients underwent a 2-week open-label anodal tDCS protocol targeting the left dorsolateral prefrontal cortex. Neural activity was tracked using a compact three-electrode EEG alongside traditional 19-electrode EEG. To capture treatment-induced changes, three complementary biomarkers were analyzed: MMN, reflecting pre-attentive auditory discrimination function; Beta oscillatory activity, associated with global attentional processes; and L1, a machine-learning-derived biomarker of cognitive engagement. CRS-R, auditory event-related potentials, and EEG-based machine learning biomarkers were recorded at baseline and immediately post-intervention. Healthy controls underwent the same baseline EEG assessments without receiving stimulation.
Results:
MMN, Beta, and L1 demonstrated task-related modulation in healthy participants across cognitive load levels. In DoC patients, changes were observed following tDCS in MMN, Beta activity, and L1 as well, with patients demonstrating complex heterogeneous response patterns. Two patients showed behavioral improvement (CRS-R), while others exhibited increased EEG reactivity without corresponding behavioral gains.
Conclusion:
These findings highlight the feasibility and potential value of integrating compact EEG systems with neuromodulation protocols to monitor neural reactivity in DoC patients, with the potential to inform and refine tDCS treatment strategies over time.
Trial Registration:
NIH Clinical Trials Registry number: NCT04614792 (https://clinicaltrials.gov/study/NCT04614792).
