1. Home>
2. Specialties>
3. Neurology>
4. Summary and Comment

Continuous EEG Monitoring in Acute Stroke

Subclinical epileptic activity is common, but what should be done about it?

These authors conducted a prospective study to determine the incidence of and risk factors for "epileptic activity" in 100 consecutive patients with acute stroke (91 ischemic, 9 hemorrhagic). During treatment in a stroke unit, the patients underwent continuous EEG (cEEG) monitoring for an average of 17.5 hours, using 10 electrodes with an 8-channel subset of the International 10-20 system. The authors considered as epileptic activity repetitive sharp waves or spikes, periodic lateralized epileptic discharges, or electrographic seizures. Patients with nonclinical epileptic activity were not treated systematically.

Epileptic activity was present in 17 of the 100 patients. Three patients had clinical seizures at stroke onset; an additional two patients had subclinical electrical seizures during cEEG monitoring. Univariate analysis identified high NIH Stroke Scale (NIHSS) score on admission, cortical involvement, and use of thrombolysis as predictors of epileptic activity. In a multivariate analysis, only the admission NIHSS score reached significance. The authors conclude that stroke patients with high NIHSS scores should undergo cEEG and that the effects of epileptic activity on outcome must be studied.

Comment: These findings add to growing evidence that continuous EEG monitoring commonly detects repetitive epileptiform discharges in patients with neurologic injury, though clinical or unequivocal electrical seizures were relatively infrequent. The latter would likely have been more common had there been a higher proportion of hemorrhagic strokes, longer monitoring time, and inclusion of patients who required intensive care.

It remains to be determined whether treatment of subclinical electrical epileptic activity is warranted, perhaps to curtail the development of post-stroke epilepsy, or whether such activity is merely a marker for more profound cortical injury. Animal studies have shown protective effects of antiepileptic drugs (AEDs), but aggressive treatment with AEDs in acutely ill patients may be detrimental (Stroke 2005; 36:583). The effects not only of seizures, but also of their treatment, on outcome must be investigated.

— Jong Woo Lee, MD, PhD

Dr. Lee is an Instructor in Neurology, Harvard Medical School and Department of Neurology, Brigham and Women’s Hospital, Boston.

Published in Journal Watch Neurology February 13, 2007

Citation(s):

Carrera E et al. Continuous assessment of electrical epileptic activity in acute stroke. Neurology 2006 Jul 11; 67:99-104.

• Original article (Subscription may be required)
• Medline abstract (Free)