Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jun 23.
doi: 10.1007/s12028-025-02301-5. Online ahead of print.

Near-Infrared Spectroscopy to Assess Covert Volitional Brain Activity in Intensive Care

Pardis Zarifkar  1 , Matthew Kolisnyk #  2 , Marwan H Othman #  1 , Melika Hassani  1 , Karen Irgens Tanderup Hansen  1 , Morten Hylander Møller  3   4 , Kirsten Møller  4   5 , Christine Sølling  5 , Jens Christian Nilsson  6 , Sigurdur Thor Sigurdsson  5 , Michael E Benros  4   7 , Jack de Jeu  2 , Karnig Kazazian  2 , John Hauerberg  8 , Kåre Fugleholm  8 , Peter F Birkeland  8 , Tobias S Andersen  9 , Jesper Kjaergaard  4   10 , Daniel Kondziella  11   12
Affiliations

Near-Infrared Spectroscopy to Assess Covert Volitional Brain Activity in Intensive Care

Pardis Zarifkar et al. Neurocrit Care. .

Abstract

Background: Detecting covert consciousness in unresponsive patients is challenging. Although functional magnetic resonance imaging and advanced electroencephalography paradigms can identify volitional brain activity, the limited accessibility of these technologies necessitates alternative approaches. Functional near-infrared spectroscopy may provide a portable solution in the intensive care unit. We assessed the feasibility of functional near-infrared spectroscopy with verbal motor commands to detect volitional brain activity in acute disorders of consciousness (DoC).

Methods: Functional near-infrared spectroscopy recordings and clinical assessments were obtained from 50 patients with DoC with acute brain injury, with data analyzed post hoc and visually at the bedside. Twenty healthy volunteers served as controls.

Results: After quality control, data from 19 controls and 36 patients were analyzed. Cortical activation was detected in 18 (96%) controls and 16 (44%) patients. Among 13 minimally conscious patients, volitional activity was found in 8 (62%), whereas 8 (35%) of 23 clinically unresponsive patients showed activation. Volitional brain activity in the latter was associated with higher odds of command following within a week, although it was not statistically significant (odds ratio 3.1, 95% confidence interval 0.7-15.8; p = 0.14). Visual bedside analysis showed high specificity (90%) but moderate agreement (κ = 0.4) with post hoc computational analysis.

Conclusions: Functional near-infrared spectroscopy with motor commands can detect volitional brain activity in acute DoC, although data quality issues remain a limitation.

Keywords: Brain injury; Cognitive motor dissociation; Coma; Consciousness; Neuromonitoring; Prognostication.

PubMed Disclaimer

Conflict of interest statement

Declarations. Conflicts of interest: The authors report no competing interests. Ethical Approval: Ethical guidelines were adhered to, and we indicate ethical approvals (institutional review board) and use of informed consent, and we confirm the use of an appropriate reporting checklist. Danish Research Ethics Committee (H-20026602).

References

    1. Schnakers C, Vanhaudenhuyse A, Giacino J, Ventura M, Boly M, Majerus S, et al. Diagnostic accuracy of the vegetative and minimally conscious state: clinical consensus versus standardized neurobehavioral assessment. BMC Neurol. 2009;9(1):35. - DOI - PubMed - PMC
    1. Edlow BL, Chatelle C, Spencer CA, Chu CJ, Bodien YG, O’Connor KL, et al. Early detection of consciousness in patients with acute severe traumatic brain injury. Brain. 2017;140(9):2399–414. - DOI - PubMed - PMC
    1. Claassen J, Doyle K, Matory A, Couch C, Burger KM, Velazquez A, et al. Detection of brain activation in unresponsive patients with acute brain injury. N Engl J Med. 2019;380(26):2497–505. - DOI - PubMed
    1. Kondziella D, Bender A, Diserens K, van Erp W, Estraneo A, Formisano R, et al. EAN panel on coma, disorders of consciousness. European academy of neurology guideline on the diagnosis of coma and other disorders of consciousness. Eur J Neurol. 2020;27(5):741–56. - DOI - PubMed
    1. Amiri M, Fisher PM, Raimondo F, Sidaros A, Cacic Hribljan M, Othman MH, et al. Multimodal prediction of residual consciousness in the intensive care unit: the CONNECT-ME study. Brain. 2023;146(1):50–64. - DOI - PubMed

LinkOut - more resources