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ARTICLES: E.G.J. Zandbergen, J. H.T.M. Koelman, R. J. de Haan, A. Hijdra for the PROPAC-Study Group SSEPs and prognosis in postanoxic coma: Only short or also long latency responses? Neurology 2006; 67: 583-586 [Abstract] [Full text] [PDF]

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SSEPs and prognosis in postanoxic coma: Only short or also long latency responses?

Diederik Zegers de Beyl   (25 September 2006)

Reply from the Authors

E.G.J. Zandgergen, J. H.T.M. Koelman, R. J. de Haan, A. Hijdra for the PROPAC-Study Group   (25 September 2006)

SSEPs and prognosis in postanoxic coma: Only short or also long latency responses? 25 September 2006
Diederik Zegers de Beyl, Hopital Erasme, Université Libre de Bruxelles Neurologie, Hopital Erasme, Route de Lennick 808, 1070 Bruxelles, Belgium Send Correspondence to journal: Re: SSEPs and prognosis in postanoxic coma: Only short or also long latency responses? diederik.zegers.de.beyl{at}ulb.ac.be Diederik Zegers de Beyl	We read with interest the article by Zandbergen et al. [1] Over 15 years ago, we found that absence of the N20 potentials within 24 hours after cardiac arrest excludes recovery of cognition [2,3] and several other groups have confirmed our experience. The prognostic significance of the N20 potential is not the same in traumatic coma however [4], and we have seen several adults who recovered cognition after head trauma despite bilateral absence of N20 on initial recordings. The article by Zandbergen et al also shows that evoked potentials do not clarify the outcome of those patients after arrest in whom the N20 potentials are preserved. Only well focused, repeated clinical examination is adequate to define the outcome. No other neurophysiologic test or imaging technique is more reliable than repeated bedside clinical testing in this group of patients. References 1. Zandbergen EGJ, Koelman JHTM, de Haan RJ, Hijdra A for the PROPAC-Study Group SSEPs and prognosis in postanoxic coma: Only short or also long latency responses? Neurology 2006; 67: 583-586. 2. Zegers de Beyl D, Borenstein S,Brunko E. Irreversible cortical damage in acute postanoxic coma: predictive value of somatosensory evoked potentials.Transplant.Proc.1984; 14:98-101. 3. Brunko E and Zegers de Beyl D. Prognostic value of early cortical somatosensory evoked potentials after resuscitation from cardiac arrest. Electroenceph Clin Neurophysiol 1987;66:15-24. 4. Delecluse F, Zegers de Beyl D, Brunko E. The bilateral absence of cortical somatosensory evoked potentials has a different importance in traumatic ans anoxic coma. Ann Neurol 1987;22:142. Disclosure: The author reports no conflicts of interest.
Reply from the Authors 25 September 2006
E.G.J. Zandgergen, Department of Neurology and Clinical Neurophysiology, Academic Medical Centre, Amsterdam D2-112, Academic Medical Centre, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands, J. H.T.M. Koelman, R. J. de Haan, A. Hijdra for the PROPAC-Study Group Send Correspondence to journal: Re: Reply from the Authors j.h.koelman{at}amc.uva.nl E.G.J. Zandgergen, et al.	We appreciate the contributions of Zegers de Beyl et al to the evaluation of SSEP for prognosis in postanoxic coma. However, only structured reviews of all relevant studies could demonstrate the predictive value of the absence of the N20 potential to have sufficient statistical reliability for use in clinical practice. [5-8] In patients with preserved N20 potentials, not only clinical testing, but also electroencephalography and biochemical testing may be useful to identify additional patients with poor prognosis. [9] We agree with Dr Zegers de Beyl that the absence of the N20 potential in other conditions leading to coma is not as reliable to indicate a poor prognosis as in patients with postanoxic coma. [6,7] References 5. Zandbergen EGJ, De Haan RJ, Stoutenbeek CP, Koelman JHTM, Hijdra A. Systematic review of early prediction of poor outcome in anoxic- ischaemic coma. Lancet 1998;352:1808-1812 6. Carter BG, Butt W. Review of the use of somatosensory evoked potentials in the prediction of outcome after severe brain injury. Crit Care Med 2001;29:178-186 7. Robinson LR, Micklesen PJ, Tirschwell DL, Lew HL. Predictive value of somatosensory evoked potentials for awakening from coma. Crit Care Med 2003;31:960-967 8. Wijdicks EFM, Hijdra A, Young GB, Bassetti CL, Wiebe S. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence based review). Report of the Quality Standards subcommittee of the American Academy of Neurology. Neurology 2006;67:203-210 9. Zandbergen EGJ, Hijdra A, Koelman JHTM, Hart AAM, Vos PE, Verbeek MM, De Haan RJ. Prediction of poor outcome within the first three days of postanoxic coma. Neurology 2006;66:62-68 Disclosure: The authors report no conflicts of interest.