Abstracts

Patients frequently present to the emergency room (ER) with mental status changes but without any immediately apparent cause. The EEG is underutilized in this population, partly due to the time and preparation required to perform it, possibly causing a delay in diagnosis. In this study, we determined if an abbreviated EEG (AEEG) performed immediately upon patient arrival to the ER could provide useful information. We specifically wanted to know if AEEGs can be useful in diagnosing non-convulsive status epilepticus (NCSE). We performed a 5-minute AEEG using a preformed electrode placement system on 25 consecutive patients who presented to the ER with mental status changes but without any immediately apparent cause as determined by ER physicians. The AEEGs were performed almost immediately after the patient arrived in the ER without the benefit of a neurologic consultation. The AEEGs were only reviewed after patient discharge and did not impact patient care. We also conducted a retrospective chart review of all enrolled patients after discharge to determine the discharge diagnosis. We then performed a Fisher exact test to determine if the cause of mental status changes could be distinguished by AEEG findings. Of 25 patients entered into the study, two had a discharge diagnosis of new onset NCSE. These patients had AEEG findings consistent with electrographic seizure activity. Seven patients were later diagnosed to have a metabolic/infectious encephalopathy. The AEEGs in four of these patients showed diffuse slowing and one had interictal epileptiform activity. Eight patients were seen due to post-ictal confusion and seven of them had AEEGs that showed diffuse slowing. Two patient were diagnosed with syncope and both had normal AEEGs. One patient had a left MCA-CVA and the AEEG showed diffuse slowing that was accentuated over the left hemisphere. One patient was diagnosed with dementia and had a normal AEEG. The diagnoses in four patients were uncertain even at the time of discharge. Three of these patients had a normal AEEG while one AEEG was uninterpretable due to movement artifact. Aside from those who were diagnosed to have NCSE, no other patient had an AEEG showing electrographic seizure activity. Using Fisher[apos]s exact test, mental status changes due to NCSE could be distinguished by the presence of electrographic seizure activity on AEEG. Our study suggests that even an abbreviated EEG performed early during the ER visit can diagnose NCSE in patients who present with mental status changes of unknown cause. Future studies with larger sample sizes would help definitively establish the utility of this technique. (Supported by University of Florida Health Sciences Center/ Jacksonville Dean[apos]s Fund Research Awards for Faculty.)