Reader response: MRI‐EEG correlation for outcome prediction in postanoxic myoclonus: A multicenter study
CalixtoMachado, Neurologist, AAN Corresponding Fellow, Insttitute of Neurology and Neurosurgery (Havana, Cuba)
Submitted June 12, 2020
Beuchat et al.1 concluded that the combination of EEG and MRI was powerful to predict good and poor outcome in patients with postanoxic myoclonus (PAM) after cardiac arrest (CA). The best test battery would be the one which proves to be powerful in predicting poor and positive outcomes.2
Short latency somatosensory evoked potentials (SSEP) is a relatively simple, non-invasive, and inexpensive bedside technique for assessing the integrity of transmission within brainstem and the cerebral cortex. The absence of the N20 response in coma after CA is consistently associated with poor outcome. SSEPs are robust against ICU conditions such as drug intoxication, hypothermia, and other metabolic disturbances.2–5
After hypoxia, selective damage of cortical neurons is possible, with preserved somatosensory responses that mainly result from the generation of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) by cortical pyramidal cells, reflecting intact ‘‘receiving characteristics’’ of the thalamo-cortical loop. Nevertheless, synaptic function may be severely disturbed in the cerebral cortex.2,3
Considering that SSEP is a reliable technique in the ICU environment and that it assesses the brainstem and cortical functions, my proposal is to consider a test battery combing MRI + EEG + SSEP for assessing its prognostic capability to identify patients with poor and good outcome in coma.2
Disclosure
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
Beuchat I, Sivaraju A, Amorim E, et al. MRI-EEG correlation for outcome prediction in postanoxic myoclonus: A multicenter study. Neurology 2020 Epub Jun 1.
Machado C, Estevez M, Rodriguez R, Carrick FR, Melillo R, Leisman G. Bilateral N20 absence in post-anoxic coma: do you pay attention? Clin Neurophysiol 2012;123:1264–1266.
van Putten MJ. The N20 in post-anoxic coma: are you listening? Clin Neurophysiol 2012;123:1460–1464.
Nobile L, Pognuz ER, Rossetti AO, et al. The characteristics of patients with bilateral absent evoked potentials after post-anoxic brain damage: A multicentric cohort study. Resuscitation 2020;149:134–140.
Karunasekara N, Salib S, MacDuff A. A good outcome after absence of bilateral N20 SSEPs post-cardiac arrest. J Intensive Care Soc 2016;17:168–170.
Beuchat et al.1 concluded that the combination of EEG and MRI was powerful to predict good and poor outcome in patients with postanoxic myoclonus (PAM) after cardiac arrest (CA). The best test battery would be the one which proves to be powerful in predicting poor and positive outcomes.2
Short latency somatosensory evoked potentials (SSEP) is a relatively simple, non-invasive, and inexpensive bedside technique for assessing the integrity of transmission within brainstem and the cerebral cortex. The absence of the N20 response in coma after CA is consistently associated with poor outcome. SSEPs are robust against ICU conditions such as drug intoxication, hypothermia, and other metabolic disturbances.2–5
After hypoxia, selective damage of cortical neurons is possible, with preserved somatosensory responses that mainly result from the generation of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) by cortical pyramidal cells, reflecting intact ‘‘receiving characteristics’’ of the thalamo-cortical loop. Nevertheless, synaptic function may be severely disturbed in the cerebral cortex.2,3
Considering that SSEP is a reliable technique in the ICU environment and that it assesses the brainstem and cortical functions, my proposal is to consider a test battery combing MRI + EEG + SSEP for assessing its prognostic capability to identify patients with poor and good outcome in coma.2
Disclosure
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References