Measuring Consciousness in the Intensive Care Unit

Brian L Edlow^{1

2}, Matteo Fecchio³, Yelena G Bodien^{3

4}, Angela Comanducci^{5

6}, Mario Rosanova⁷, Silvia Casarotto^{5

7}, Michael J Young³, Jian Li^{3

8}, Darin D Dougherty^{8

9}, Christof Koch^{10

11}, Giulio Tononi¹², Marcello Massimini^{5

7}, Melanie Boly¹³

Affiliations

¹ Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. bedlow@mgh.harvard.edu.
² Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA. bedlow@mgh.harvard.edu.
³ Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
⁴ Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Harvard Medical School, Charlestown, MA, USA.
⁵ IRCCS Fondazione Don Carlo Gnocchi Onlus, Milan, Italy.
⁶ Università Campus Bio-Medico di Roma, Rome, Italy.
⁷ Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy.
⁸ Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
⁹ Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
¹⁰ MindScope Program, Allen Institute, Seattle, WA, USA.
¹¹ Tiny Blue Dot Foundation, Santa Monica, CA, USA.
¹² Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA.
¹³ Department of Neurology, University of Wisconsin-Madison, Madison, WI, USA.

PMID: 37029315
PMCID: PMC11421303
DOI: 10.1007/s12028-023-01706-4

Measuring Consciousness in the Intensive Care Unit

Brian L Edlow et al. Neurocrit Care. 2023 Jun.

. 2023 Jun;38(3):584-590.

doi: 10.1007/s12028-023-01706-4. Epub 2023 Apr 8.

Authors

Affiliations

¹ Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. bedlow@mgh.harvard.edu.
² Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA. bedlow@mgh.harvard.edu.
³ Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
⁴ Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Harvard Medical School, Charlestown, MA, USA.
⁵ IRCCS Fondazione Don Carlo Gnocchi Onlus, Milan, Italy.
⁶ Università Campus Bio-Medico di Roma, Rome, Italy.
⁷ Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy.
⁸ Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
⁹ Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
¹⁰ MindScope Program, Allen Institute, Seattle, WA, USA.
¹¹ Tiny Blue Dot Foundation, Santa Monica, CA, USA.
¹² Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA.
¹³ Department of Neurology, University of Wisconsin-Madison, Madison, WI, USA.

PMID: 37029315
PMCID: PMC11421303
DOI: 10.1007/s12028-023-01706-4

Abstract

Early reemergence of consciousness predicts long-term functional recovery for patients with severe brain injury. However, tools to reliably detect consciousness in the intensive care unit are lacking. Transcranial magnetic stimulation electroencephalography has the potential to detect consciousness in the intensive care unit, predict recovery, and prevent premature withdrawal of life-sustaining therapy.

Keywords: Coma; Complexity; Consciousness; Transcranial magnetic stimulation electroencephalography (TMS-EEG).

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Conflict of interest statement

Conflicts of Interest:

C.K. and G.T. are Board Members, and C.K., G.T., and M.M. have a financial interest in Intrinsic Powers Inc. G.T. holds patent rights along with the Wisconsin Alumni Research Foundation (WARF): patent No. US 8,457,731 B2, and patent applications WARF No. P220191, P220192.

Figures

**Figure. 1.. Stimulating the brain to determine its capacity for consciousness.**
(A) A technologist (left) with expertise in transcranial magnetic stimulation-electroencephalography (TMS-EEG) measures the perturbational complexity index (PCI) in a patient with a severe traumatic brain injury (center), while a physician observes (right). The technician stimulates the right premotor cortex based on precise anatomic guidance provided by the T1-weighted magnetic resonance imaging (MRI) scan on the top of the left screen. A functional MRI connectivity map is used to identify cortical sites to be targeted (e.g., highly connected regions shown in red are likely to have higher PCI values). The turquoise aiming device on the bottom left of the screen provides real-time feedback about the precision of target stimulation. On the right screen, the technologist visually assesses for artifacts and determines the reliability of TMS-evoked potentials recorded by 19 EEG electrodes. In this illustrative patient, the PCI value of 0.48 is above the empirically derived cut-off of 0.31, indicating that the patient’s brain has the same complexity as that of conscious subjects. (B) TMS-evoked EEG waveforms that indicate low (black), moderate (gray), and high (green) potential for recovery of behavioral signs of consciousness. These waveforms are adapted from Casarotto et al. 2016 [19], where low potential for recovery was observed with PCI = 0, moderate potential for recovery with 0 < PCI ≤ 0.31, and high potential for recovery with PCI > 0.31. Abbreviations: A = anterior; I = inferior; L = left; P = posterior; R = right; S = superior.

See this image and copyright information in PMC

References

1. Giacino JT and Kalmar K, The vegetative and minimally conscious states: A comparison of clinical features and functional outcome. J Head Trauma Rehabil, 1997; 12: 36–51.
1. Roozenbeek B, et al., Prediction of outcome after moderate and severe traumatic brain injury: external validation of the International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) and Corticoid Randomisation After Significant Head injury (CRASH) prognostic models. Crit Care Med, 2012; 40: 1609–17. - PMC - PubMed
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Measuring Consciousness in the Intensive Care Unit

Affiliations

Measuring Consciousness in the Intensive Care Unit

Authors

Affiliations

Abstract

Conflict of interest statement

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