Bedside quantitative electroencephalography improves assessment of consciousness in comatose subarachnoid hemorrhage patients.

TitleBedside quantitative electroencephalography improves assessment of consciousness in comatose subarachnoid hemorrhage patients.
Publication TypeJournal Article
Year of Publication2016
AuthorsClaassen, Jan, Velazquez Angela, Meyers Emma, Witsch Jens, M Falo Cristina, Park Soojin, Agarwal Sachin, J Schmidt Michael, Schiff Nicholas D., Sitt Jacobo D., Naccache Lionel, E Connolly Sander, and Frey Hans-Peter
JournalAnn Neurol
Date Published2016 10
KeywordsAged, Coma, Consciousness Disorders, Electroencephalography, Female, Humans, Male, Middle Aged, Neurologic Examination, Neurophysiological Monitoring, Point-of-Care Testing, Retrospective Studies, Subarachnoid Hemorrhage

OBJECTIVE: Accurate behavioral assessments of consciousness carry tremendous significance in guiding management, but are extremely challenging in acutely brain-injured patients. We evaluated whether electroencephalography (EEG) and multimodality monitoring parameters may facilitate assessment of consciousness in patients with subarachnoid hemorrhage.

METHODS: A retrospective analysis was performed of 83 consecutively treated adults with subarachnoid hemorrhage. All patients were initially comatose and had invasive brain monitoring placed. Behavioral assessments were performed during daily interruption of sedation and categorized into 3 groups based on their best examination as (1) comatose, (2) arousable (eye opening or attending toward a stimulus), and (3) aware (command following). EEG features included spectral power and complexity measures. Comparisons were made using bootstrapping methods and partial least squares regression.

RESULTS: We identified 389 artifact-free EEG clips following behavioral assessments. Increasing central gamma, posterior alpha, and diffuse theta-delta oscillations differentiated patients who were arousable from those in coma. Command following was characterized by a further increase in central gamma and posterior alpha, as well as an increase in alpha permutation entropy. These EEG features together with basic neurological examinations (eg, pupillary light reflex) contributed heavily to a linear model predicting behavioral state, whereas brain physiology measures (eg, brain oxygenation), structural injury, and clinical course added less.

INTERPRETATION: EEG measures of behavioral states provide distinctive signatures that complement behavioral assessments of patients with subarachnoid hemorrhage shortly after the injury. Our data support the hypothesis that impaired connectivity of cortex with both central thalamus and basal forebrain underlies decreasing levels of consciousness. Ann Neurol 2016;80:541-553.

Alternate JournalAnn. Neurol.
PubMed ID27472071
PubMed Central IDPMC5042849
Grant ListR01 LM011826 / LM / NLM NIH HHS / United States
UL1 RR024156 / RR / NCRR NIH HHS / United States
UL1 TR000040 / TR / NCATS NIH HHS / United States

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