Intracortical electroencephalography in acute brain injury

Authors

  • Allen Waziri MD,

    Corresponding author
    1. Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY
    • Department of Neurosurgery, University of Colorado Health Sciences Center, 12631 East 17th Avenue, Campus Box C-307, Aurora, CO 80045
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  • Jan Claassen MD,

    1. Division of Critical Care Neurology, Columbia University College of Physicians and Surgeons, New York, NY
    2. Comprehensive Epilepsy Center, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • R. Morgan Stuart MD,

    1. Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY
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  • Hiba Arif MD,

    1. Comprehensive Epilepsy Center, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • J. Michael Schmidt PhD,

    1. Division of Critical Care Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • Stephan A. Mayer MD,

    1. Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY
    2. Division of Critical Care Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • Neeraj Badjatia MD, MSc,

    1. Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY
    2. Division of Critical Care Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • Lewis L. Kull REEGT,

    1. Comprehensive Epilepsy Center, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • E. Sander Connolly MD,

    1. Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY
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  • Ronald G. Emerson MD,

    1. Comprehensive Epilepsy Center, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • Lawrence J. Hirsch MD

    1. Comprehensive Epilepsy Center, Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY
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  • Potential conflict of interest: Nothing to report.

Abstract

Objective

Continuous electroencephalography (EEG) is used in patients with neurological injury to detect electrographic seizures and clinically important changes in brain function. Scalp EEG has poor spatial resolution, is often contaminated by artifact, and frequently demonstrates activity that is suspicious for but not diagnostic of ictal activity. We hypothesized that bedside placement of an intracortical multicontact electrode would allow for improved monitoring of cortical potentials in critically ill neurological patients.

Methods

Sixteen individuals with brain injury, requiring invasive neuromonitoring, underwent implantation of an eight-contact minidepth electrode.

Results

Intracortical EEG (ICE) was successfully performed and compared with scalp EEG in 14 of these 16 individuals. ICE provided considerable improvement in signal-to-noise ratio compared with surface EEG, demonstrating clinically important findings in 12 of 14 patients (86%) including electrographic seizures (n = 10) and acute changes related to secondary neurological injury (n = 2, 1 ischemia, 1 hemorrhage). In patients with electrographic seizures detected by ICE, scalp EEG demonstrated no concurrent ictal activity in six, nonictal-appearing rhythmic delta in two, and intermittently correlated ictal activity in two. In two patients with secondary neurological complications, ICE demonstrated prominent attenuation 2 to 6 hours before changes in other neuromonitoring modalities and more than 8 hours before the onset of clinical deterioration.

Interpretation

ICE can provide high-fidelity intracranial EEG in an intensive care unit setting, can detect ictal discharges not readily apparent on scalp EEG, and can identify early changes in brain activity caused by secondary neurological complications. We predict that ICE will facilitate the development of EEG-based alarm systems and lead to prevention of secondary neuronal injury. Ann Neurol 2009;66:366–377

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