Covert brain complexity in the intensive care unit.
Matteo Fecchio, David R Schreier, Morgan K Cambareri, Veronica Nisticò, Holly J Freeman, Phoebe K Lawrence, Yelena G Bodien, Michael J Young, Ona Wu, Brian L Edlow
Cortex; a journal devoted to the study of the nervous system and behavior August 1, 2026 DOI: 10.1016/j.cortex.2026.03.021 (opens in new tab) via PubMed
Summary
AI-generated from the abstractThis proof-of-concept report describes the use of transcranial magnetic stimulation with electroencephalography (TMS-EEG) to assess consciousness in a critically ill patient with severe brain injury in the acute stage. Standard multimodal assessments, including behavioral exams, task-based fMRI, and task-based EEG, suggested a vegetative state/unresponsive wakefulness syndrome. TMS-EEG, which directly engages corticothalamic circuits to compute the perturbational complexity index (PCI), detected signs of consciousness that these advanced evaluations missed. The authors demonstrate the feasibility of TMS-EEG as part of a multimodal protocol for consciousness assessment in the intensive care unit, potentially improving early detection and prognostication.
Study at a glance
| Characteristics | Case study / proof-of-concept Case report Peer reviewed |
|---|---|
| Sample size | 1 |
| Population | Critically ill patient with severe brain injury in the acute stage |
| Keywords | Coma Consciousness Electroencephalography Intensive care unit Transcranial magnetic stimulation |
| Key finding | TMS-EEG detected signs of consciousness in a critically ill acute-stage patient that standard multimodal assessments (behavioral, fMRI, EEG) did not, suggesting its potential to improve early detection. |
Abstract
Early detection of consciousness in critically ill patients with severe brain injuries can profoundly impact prognostication and clinical care decisions. Advanced multimodal protocols to detect signs of consciousness include standardized behavioral assessments, task-based functional magnetic resonance imaging (fMRI), and task-based electroencephalography (EEG). However, these approaches have limited diagnostic sensitivity because patients may lack auditory function, attention, language, or other cognitive capacities required to perform a task or process a sensory stimulus, even if they are conscious. Transcranial magnetic stimulation EEG (TMS-EEG) has the potential to overcome these limitations by directly engaging corticothalamic circuits to compute the perturbational complexity index (PCI), an emerging indicator of consciousness. To date, TMS-EEG studies have focused on patients in the subacute or chronic stage of recovery from severe brain injury. Here, we report the proof-of-concept application of TMS-EEG for a critically ill patient in the acute stage of brain injury, in which multimodal assessments suggested a vegetative state/unresponsive wakefulness syndrome. We demonstrate that TMS-EEG may detect signs of consciousness that elude current advanced evaluations, showing the feasibility of TMS-EEG as part of a multimodal protocol for assessing consciousness in the intensive care unit.