EEG and cerebral ischaemia are common and the methodology is widely available in intensive care units. Known as cerebral vasospasm in the old days, localized ischaemia is a much feared complication of subarachnoid hemorrhage. In a study of 103 patients who underwent continuous EEG for a mean of 8 days after subarachnoid hemorrhage, late onset epileptiform discharges had the highest predictive power for delayed cerebral ischaemia. There was a lot of retrospective data that already indicated that continuous EEG could accurately predict this very serious complication of subarachnoid hemmorrhage, localized ischaemia. New regional increase in slow waves and new dropout in regional alpha activity, long trends of alpha variability, worsening of alpha/delta ratio, taken together, also made the alarms in the system alert clinicians to delayed iscahemia.
This was a double-blind prospective study of EEG and cerebral ischaemia with controls without subarachnoid hemmorrhage, and the results have been praised by investigations connected or not to the study, as a means of predicting events that cause aphasia, motor weakness and coma. Continuous EEG with alarms is a non-invasive method, of relatively low cost, which may be used long-term in these patients. EEG in cerebral ischaemia may be a good idea.
Rosenthal et al. Ann Neurol 2018 Epub 2018 April 16
Dr Paulo Bittencourt
