Abstracts

Rationale: More than twenty percent of patients aged over 70 years old admitted to the emergency room (ER) have an acute confusional state (ACS). Among those, over ten percent have non convulsive status epilepticus (NCSE). Yet, an epileptic origin of delirium is often overlooked. Routine 20 minutes EEGs miss most seizures compared to continuous EEG monitoring (cEEG). The aim of this work was to determine whether cEEG could be a useful tool in the assessment of ACS in the elderlyMethods: We screened our cEEG database from 2007 to June 2011 for patients over 75 years with a clinical diagnosis of ACS. We studied the clinical, biological and imaging characteristics of these patients and compared the anomalies found on routine EEG and cEEG. Results: 14 % (48/343) of the cEEG were realised in elderly patients. 31 % (15/48) of those were done for ACS. Mean age was 84 years. 81 % of patients were female. All patients had routine EEG before cEEG. Routine EEG did not reveal any epileptic anomalies in 7/15 patients. Among those, cEEG identified interictal epileptiform discharges (IID) in 2 and NCSE in 1. Delay between routine EEG and cEEG was 5.3 days and time to find EEG anomalies during cEEG was over thirty minutes in one patient with NCSE. For these patients, with a negative routine EEG, cEEG was considered only after the rest of work-up returned negative (biology, iconography and spinal tap). In 8/15 patients, routine EEG revealed epileptic anomalies, including 3 with IID, 1 with periodic lateralized discharges, 2 with non convulsive seizures (NCSz) and 2 with NCSE. Among patients with only IID, cEEG revealed NCSz in 1 and NCSE in 2. Delay between routine EEG and cEEG was 2.75 days and time to find EEG anomalies during cEEG was over thirty minutes in the two patients with NCSE Conclusions: In our series, cEEG in elderly with ACS showed NCSE, NCSz and IID that routine EEG missed in 3/7 (40 %) patients. NCSE was the cause of ACS in 5/15 (33%) patients. More than half of the NCSE were missed by routine EEG. cEEG is more sensitive than routine EEG in detecting epileptic anomalies in elderly patients with ACS and should probably be considered early in the work up