Abstracts

Rationale: Video EEG monitoring is often performed in patients with prolonged unexplained acute mental status change to determine if they are in non-convulsive status. Status epilepticus is defined as prolonged seizures or recurrent seizures without complete recovery in between, lasting more than 30 minutes. The definition is relatively easy to apply for patients with motor manifestations during seizures but can be challenging in patients with non-convulsive seizures which may have discrete electrographic seizures with discrete clinical symptoms, electrographic seizures without any clinical symptoms and electrographic seizures leading to prolonged clinical symptoms without recovery in between fulfilling the criteria for status epilepticus. Herein, we investigated the seizures semiology of patients with known brain tumors admitted for unexplained mental status change who underwent video EEG monitoring and were found to have electrographic seizures. Methods: We present a retrospective review of patients admitted between 1/2010 and 12/2012 with central nervous system neoplasms who underwent continuous video EEG monitoring (cvEEG) for altered mental status. Patients in the immediate post-operative period were excluded. Seizures were classified as clinical and non-clinical. Clinical symptoms were divided into (1) motor manifestations, (2) discrete alteration of awareness or cognitive function correlating with EEG seizure activity and (3) prolonged alteration of awareness or cognitive function without detectable change between electrographic seizures but noticeable improvement after the EEG seizures were controlled. Results: 161 patients underwent cvEEG monitoring. 39 patients were found to have electrographic seizures, some on multiple occasions leading to 53 prolonged cvEEG admissions. Overall seizure frequency was 1/hr (range 1/d to continuous). Eight patients showed motor manifestations during their electrographic events, 25 patients had discrete changes of responsiveness or cognitive function (e.g. aphasia) with their electrographic seizures. Nine patients showed noticeable improvement within 24 hours after cessation of electrographic seizures. 11 patients had no changes during their electrographic events and did not improve after the electrographic seizure activity ended. Conclusions: Patients with recurrent non-convulsive seizures on video EEG monitoring may not recover in between the seizures and can be considered as being in non-convulsive status. In patients with non-motor seizures presenting with cognitive impairment and decreased responsiveness, repeated cognitive testing is necessary to determine the correlation between electrographic seizures and clinical symptoms which may not become apparent until after the seizures have stopped.