New findings encourage more vigilant monitoring of seizure activity among intensive care patients.

Two new studies published by neurologists at Columbia University Medical Center and NewYork-Presbyterian Hospital demonstrate a need for more vigilant monitoring for seizure activity among intensive care patients who may be experiencing subtle seizures that are typically unrecognized. These subtle seizures may be affecting patients' prognoses and causing long-term brain damage, death and severe disability (see also Columbia University Medical Center).

Published in recent issues of the Annals of Neurology and Critical Care Medicine, both studies were led by Lawrence J. Hirsch, M.D., associate clinical professor of neurology, Columbia University Medical Center, and director of the Continuous EEG Monitoring Program at the Comprehensive Epilepsy Center at NewYork-Presbyterian Hospital/Columbia. His group, in conjunction with Drs. Stephan Mayer and Jan Claassen of the Neurological Intensive Care Unit (NICU) at NewYork-Presbyterian Hospital/Columbia, has previously shown that unrecognized seizures are common in the critically ill, particularly in those with acute brain injury, and that these seizures are associated with unfavorable outcomes. NewYork-Presbyterian/Columbia's Continuous EEG Monitoring Program is one of the largest and most academically productive in the world.

The two studies found that electroencephalography was effective in detecting subtle seizures that are often impossible to detect by visual observation. Findings demonstrated the value of continuous EEG (where electrodes are placed on the scalp - a noninvasive procedure used in nonsurgical ICUs) and intracranial EEG (ICE), an invasive technology where a probe is placed in the cortex of the patient's brain. ICE is mainly used in Neurological ICUs for serious acute brain injuries, such as subarachnoid hemorrhage, severe head trauma and very large strokes (hemorrhagic or ischemic), which require other invasive brain monitoring devices.

"Monitoring for seizure activity in intensive care patients is important in order to identify small, clinically invisible seizures, which might explain why patients are not waking up - namely, because they are having lots of mini-seizures in multiple locations. Treating these clinically silent seizures may lead to improved alertness, reverse ongoing brain dysfunction, and prevent progressive injury to brain cells," says Dr. Hirsch. "Intracortical electroencephalography (ICE) appears to be the preferred method to monitor seizure activity in patients requiring other invasive brain monitoring (standard in the NewYork-Presbyterian/Columbia ...