Study confirms importance of EEG as diagnostic tool in ICU

Bleeding in and around the brain (cerebral hemorrhage, including intra-cerebral hemorrhage, subdural hematoma, subarachnoid hemorrhage among other forms), from whatever cause (stroke, ruptured aneurysm, stroke, tumor, trauma, etc) can be very irritating to the electrical cells of the brain and affect how these cells transmit signals. If cells become very irritated and/or hyperactive, seizures can occur.

A study reported today at the 64th American Epilepsy Society Annual Meeting has found that, of patients with a cerebral hemorrhage or hematoma, one in four had a diagnosis of sub-clinical seizures while in the ICU: sub-clinical seizures can only be detected with continuous electroencephalographic (EEG) recording.

The investigators reviewed the records of more than 950 cerebral hemorrhage and hematoma patients consecutively admitted to the intensive care unit during a period of more than three years. Only a portion (20%) of these patients had received routine EEG or continuous EEG evaluation. Seizures were detected in 25% of patients who had been evaluated, with no significant difference in seizure activity found among the different types of intra-cranial hemorrhage.

Continuous EEG detected seizure activity in a much higher percentage of patients than routine EEG. Seizure activity in nearly all cases was sub-clinical and compatible with a diagnosis of (non-convulsive) continuous seizure activity (status epilepticus).

Lead investigator Jeffrey M. Politsky, M.D., and colleagues report that, "The fact that 700 patients with cerebral hemorrhage did not undergo EEG evaluation suggests that the diagnosis of sub-clinical seizures was missed in over 200 cases. Missing a diagnosis of sub-clinical seizures might well have a negative impact on patient outcome.

"Our study confirms the importance of continuous EEG as a diagnostic tool in the ICU. A more detailed analysis of the relationship of seizures in the acute setting of cerebral hemorrhage and patient outcome is needed."