{"doi":"10.1002/ana.78085","title":"Early Detection of Covert Consciousness With Functional Near‐Infrared Spectroscopy","abstract":"Advances in the evaluation and management of patients with disorders of consciousness have revealed a pressing need to disentangle the cognitive capacities of the injured brain from overt behavior, particularly when ordinary avenues of self-expression are lost, limited, or obscured.1 Although the understanding that consciousness and related qualities of subjective experience cannot be adequately assessed through behavior alone has been long contemplated by philosophers,2-4 the clinical realization that a patient's vitiated motoric repertoire does not imply unconsciousness was only more recently empirically established through functional neuroimaging and electroencephalography (EEG)-based studies, wherein behaviorally unresponsive patients, when asked to imagine or attempt actions, have demonstrated corresponding cortical activation. In such paradigms, when a time-locked, task-appropriate pattern appears, it suggests residual comprehension and cognitive control sufficient to volitionally follow a verbal instruction, and is accordingly interpreted as evidence of covert consciousness (also known as cognitive motor dissociation).5-9 Although the worldwide incidence and prevalence of covert consciousness has yet to be systematically studied, limited estimates have been as high as 25%,10 signaling a phenomenon of substantial public concern that clinicians and society are beginning to contend with.11 Kazazian and colleagues extend this lesson in the intensive care unit (ICU) setting by demonstrating that functional near-infrared spectroscopy (fNIRS), a portable bedside imaging technology that indirectly measures cortical function by detecting changes in cerebral blood oxygenation through near-infrared light absorption, may detect engagement in cognitive tasks among behaviorally unresponsive, acutely brain injured patients.12 Of 32 critically ill patients studied in a prospective, single arm, single site study, 8 (25%) displayed evidence of volitional modulation of brain activity in response to motor imagery commands, a finding seen not only among patients considered to be in the vegetative state / unresponsive wakefulness syndrome (VS/UWS, N = 5) or low-level minimally conscious state (MCS–, N = 1), but also in coma (N = 2),12 underscoring the potential for profound severance of cognitive and motor function during early care windows when clinical decisions are most consequential. The findings and their implications raise important clinical, epistemological, and ethical questions (see the Table 1), many still unsettled as this field advances apace. In the years since the release of American13, 14 and European15 professional society guidelines recommending evaluation for covert consciousness in settings of diagnostic ambiguity, only a handful of medical centers worldwide have demonstrated capabilities to perform such assessments.16 Consequently, most patients and clinicians who might benefit from covert consciousness testing lack access. This implementation gap may be distressing not only for family members eager to understand their loved one's level of awareness and capacity for recovery following critical illness or injury, but also for clinicians aspiring to provide guideline-concordant care and counseling. The reasons for this gap are numerous and generally underexamined. They span issues of inconsistent access to the requisite neurotechnologies, analytical expertise, clinical validation, workflow management, and regulatory hurdles.17 Functional magnetic resonance imaging (fMRI), for example, typically demands transport out of the ICU, MRI-compatible monitoring, patient tolerance of recumbency in the scanner, and robust analytic infrastructure. Advanced EEG is more portable, yet provides comparatively limited spatial resolution, requires sophisticated data processing pipelines, and analytical expertise that most medical centers lack. Unlike neurobehavioral assessment,18 the practical challenge of serially administering these tests ","journal":"Annals of Neurology","year":2025,"id":529197,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9604,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":644019,"name":"Michael J. Young","orcid":"0000-0001-6661-0811","position":0,"is_corresponding":true}],"reference_count":47,"raw_metadata":null,"created_at":"2026-07-19T02:50:56.971987Z","pmid":"41147926","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}