Epilepsia, 47(1):207–210, 2006 Blackwell Publishing, Inc. C  2006 International League Against Epilepsy Case Reports Beta Activity in Status Epilepticus ∗ Leo H. Bonati, ∗ Yvonne Naegelin, †Heinz-Gregor Wieser, ∗ Peter Fuhr, and ∗ Stephan Ruegg ∗ Department of Neurology, Division of Clinical Neurophysiology, University Hospital Basel, Basel, and †Department of Neurology, Division of Epileptology and Electroencephalography, University Hospital Zurich, Zurich, Switzerland Summary: Focal beta activity on scalp EEG is a rare seizure pattern that has most extensively been studied in patients un- dergoing evaluation for epilepsy surgery. However, ictal beta activity is uncommon beyond this population and has not been reported in human status epilepticus. We observed ictal focal beta activity as the predominant seizure pattern in a patient with refractory status epilepticus. Continuous left temporal beta ac- tivity clinically correlated with complex partial semiology on video-EEG. Key Words: Beta activity—Refractory status epilepticus—Electroencephalography. Focal beta activity is a rare electroencephalographic seizure pattern that has predominantly been reported in patients with intractable seizure disorders. In a study of 16,432 consecutive scalp EEGs, interictal and ictal focal beta activity was present in 28 patients, mostly children with epilepsies secondary to arteriovenous malformations, porencephalic cysts, or tumors (1). More recently, ictal beta activity on scalp EEG (2–4) and intracranial EEG (5) was described in patients with neocortical epilepsies undergoing presurgical evaluation. However, few data ex- ist on this seizure pattern beyond such patients, and we have not found any reports describing it in human sta- tus epilepticus. We report on a patient with temporal lobe epilepsy, in whom focal beta activity became the only electroencephalographic seizure pattern in the late phase of refractory status epilepticus. CASE REPORT A 52-year-old woman was admitted to our hospital with an acute confusional state. The patient had a medical his- tory of temporal lobe epilepsy since age 18 years. She was last seen in our outpatient clinic 3 years ago; at that time, antiepileptic treatment consisted of carbamazepine (CBZ; 600 mg/d) and lamotrigine (50 mg/d), and the patient experienced an average of two complex partial Accepted July 22, 2005. Address correspondence and reprint requests to Dr. L.H. Bonati at Department of Neurology, Division of Clinical Neurophysiology, Uni- versity Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. E-mail: bonatil@uhbs.ch seizures with secondary generalization per year. On cur- rent admission, serum levels of both antiepileptic drugs (AEDs) were not detectable. Drug screening was positive for methaqualone. Assuming nonconvulsive status epilep- ticus (NSCE), the patient was transferred to the intensive care unit and treated with IV lorazepam and valproic acid. Video-EEG on the day after admission revealed no epileptiform potentials, but repeatedly showed brief spindle-like beta activity in the left temporal region of 1– 2 s duration, with amplitudes ranging up to 150 μV. This activity appeared 13 times during 20 min of EEG record- ing. On day 3, intermittent tonic–clonic seizures occurred, and anesthetic treatment with IV midazolam (MDL) and propofol was added. EEG showed burst-suppression activ- ity, yet bitemporal and generalized spikes and sharp-waves were present during burst phases, despite dose escalation of anesthetic treatment. Pentobarbital (PTB) was started on day 9, leading to complete suppression of EEG activity. After temporary reduction of the PTB dose due to cardiac failure, burst-suppression activity with generalized sharp waves reappeared. Because of PTB-induced gastric palsy and liver toxicity, the treatment was switched to high-dose IV MDL on day 27 (≤4 mg/min). Thereafter, EEG re- peatedly showed unilateral temporal runs of beta activity with increasing and decreasing amplitude, with consecu- tive evolution into rhythmic alpha activity, sometimes fol- lowed by rhythmic sharp waves. This evolution was char- acterized by gradual increase of amplitude and decrease of frequency. The described pattern occurred predominantly on the left side and lasted between 1 and 2 min. On the ba- sis of a putative inflammatory component after more than 207