Emergency EEG and diagnostic yield.

The aim of the study was to determine whether an acute loss of consciousness, mental status change or related symptoms correlated with the presence of epileptiform abnormalities on urgent EEG. We analyzed 228 consecutive patients admitted to Emergency Room during the past 12 months and referred for urgent EEG evaluation. All patients had either a brief loss of consciousness or acute brain disorder, with a clinical diagnosis of epilepsy, syncope, head trauma, headache, transient ischemic attack (TIA) or vertigo. Statistical analysis was performed using Spearman's rho test for group comparison and multivariate regression analysis. The mean age of patients was 48 +/- 20 years. The frequency of referring clinical diagnoses was as follows: epilepsy 44.7% (102/228), TIA 15.8% (36/228), syncope 15.4% (35/228), headache 11% (25/228), vertigo 7.9% (18/228) and acute head trauma 5.3% (12/228). EEG indicated epileptiform abnormalities in 14.9% (34/228) and focal slowing in 9.2% (21/228) of patients. The majority of them (26%; 21/81) had a clinical diagnosis of epilepsy. There was a significant correlation between clinical diagnosis of epilepsy and epileptiform EEG (Spearman's rho = 0.13; P < 0.04). Multivariate regression analysis showed that there was no predictive value in the clinical diagnosis of epilepsy and epileptiform EEG (beta = 1.483, P = 0.16). In conclusion, epilepsy was the most common clinical diagnosis in patients referred for urgent EEG. There was a significant correlation between the diagnosis and specific EEG abnormalities, however, the diagnosis of epilepsy failed to predict epileptiform activity on EEG. Study results suggested urgent EEG to have a high yield in patients with epilepsy.