The article by Madl et al entitled "Detection of Nontraumatic Comatose Patients With No Benefit of Intensive Care Treatment by Recording of Sensory Evoked Potentials," which appeared in the June 1996 issue of the Archives, confirms an extensive body of literature demonstrating that bilateral absence of cortical evoked potentials predicts brain death without awakening and provides a useful marker for those comatose patients with hopeless prognoses.
However, among their patients with preserved cortical N20 peaks, there was substantial mortality, with only 42% surviving to hospital discharge. The authors attempt to distinguish between survivors and nonsurvivors by analyzing the latency between the cervicomedullary N13 peak and cortical N20 peak, as well as the amplitude of the N20 peak, but neither is significant.
Our experience with 50 patients who experienced hypoxic-ischemic coma after cardiopulmonary resuscitation clarifies the uses and limitations of evoked potentials in this setting.1 We correlated evoked responses and
Rothstein TL. The Role of Evoked Potentials in Coma. Arch Neurol. 1997;54(1):17-18. doi:10.1001/archneur.1997.00550130009005