Continuous EEG recording in the intensive care unit: epileptiform activity

Background

Digital EEG technology has recently become available for long-term ICU recordings. Epileptiform activity, as seizures or spikes, is worthy of detection, as this often indicates structural brain lesions, and seizures may contribute to further damage.

Methods

Adult patients in our general ICU were randomized into two groups: those who received continuous digital EEG (CEEG) and those who had standard, 20-min recordings. We excluded those in coma after cardiac arrest and others for whom the prognosis was deemed to be hopeless for significant recovery.

Results

Of patients with acute structural brain lesions (ASBLs), 31 had CEEG and 21 had standard care; each group was similar for age, sex ratio and initial Glasgow Coma Scale scores. Of these, 10 of the 32 (32%) CEEG patients and only two of the 21 (9.5%) of the standard group had showed epileptiform activity (P < 0.05). In two separate, comparable groups of patients with metabolic encephalopathies, two of 24 (8%) patients with CEEG and zero of 13 (0%) with standard care showed epileptiform activity (P = 0.04).

Conclusions

CEEG monitoring of patients with ASBLs gives a considerably higher yield of epileptiform activity than standard EEG in these patients or CEEG or standard EEG in patients with metabolic disorders. This has implications for further study and resource utilization.