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60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

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Quantification of cerebral coma: the prognostic value of Mismatch Negativity (MMN)

Meeting Abstract

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  • M. Morgalla - Neurochirurgische Klinik, Universitätsklinikum Tübingen
  • P. Magunia - Neurochirurgische Klinik, Universitätsklinikum Tübingen
  • M. Tatagiba - Neurochirurgische Klinik, Universitätsklinikum Tübingen

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocMO.02-05

doi: 10.3205/09dgnc005, urn:nbn:de:0183-09dgnc0056

Published: May 20, 2009

© 2009 Morgalla et al.
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Outline

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Objective: The outcome prediction of patients with cerebral coma has an important impact on treatment decisions in a neurosurgical intensive care unit (ICU). Event-related potentials (ERP) like Mismatch Negativity (MMN) are electrophysiological scalp-recorded potentials which reflect higher processing of incoming sensory information. They are related to consciousness, focal attention, and cognition. We tested the hypothesis that in comatose patients the presence of MMN-potentials is associated with a good clinical outcome.

Methods: From March to July of 2007 we prospectively studied 21 patients in our ICU. The aetiology of the coma differed (intracerebral bleeding=14, head injury=6, anoxia=1). To evoke MMN we used a passive Oddball-paradigm (2000 stimuli, 90% at 1000Hz, 10% at 1500Hz, 85dB, duration 70ms, ISI=500ms) delivered binaurally. Neurophysiological responses were recorded from 4 electrodes (Fpz, Fz, A1, A2). To evaluate the measurements, we also sampled the neurophysiological data of 20 healthy volunteers. In addition to the MMN we also examined the patients’ pupillary light reflex, N100-, AEP and SSEP-potentials. The outcome of the patients was examined 3 months after the onset of coma using the Glasgow-Outcome-Scale (GOS).

Results: The group comparison between healthy volunteers and comatose patients showed a statistically significant difference regarding MMN- (p<0.0001) and N100-amplitudes (p=0.0087). There was no statistically significant correlation between MMN and the 3-months outcome (31% sensitivity, 60% specifity, 71% PPV, 21% NPV). Among the assessed markers only the SSEP significantly correlated with the coma-outcome (p=0.0049). The presence of SSEPs predicted positive outcome (GOS>=3) reliably (100% sensitivity, 75% specifity, 93% PPV). The known good prognostic value of SSEPs for negative outcome (GOS<=2) could be confirmed (p=0.0049, NPV=100%).

Conclusions: MMN recording in comatose patients did not provide reliable information of a possible positive outcome. Therefore, MMN did not serve as an additional parameter of the prognosis of coma in an ICU setting. However, the established evaluation of the SSEPs provided a reliable prediction of the clinical outcome.