Diagnostic decision-making after a first and recurrent seizure in adults

PURPOSE The role of EEG after a first seizure has been debated. Epileptiform EEG activity is a good predictor of seizure recurrence, but is reported in only 8-50% of first-seizure adult patients. Even if the EEG is abnormal, the opinions about treatment after a first seizure differ. The role of EEG in treatment decisions after remission or recurrence is also unclear. This study aims to identify neurologists' diagnostic strategies compared to guidelines about the use of EEG (i) after a first unprovoked generalized seizure in adults, (ii) after a recurrent seizure and (iii) in treatment decisions after recurrence or remission. METHOD All members of the Dutch Neurological Society were invited to participate in our on-line survey about the use of EEG after a first seizure, after recurrent seizures and in treatment decisions. Ten percent (N=110) of invitees participated, including mainly clinical neurophysiologists, general neurologists and neurologists-in-training. RESULTS Ninety-five percent of the respondents would request a routine EEG after a first seizure. After normal MRI and EEG findings, 4% would record a second routine EEG, 48% a sleep-deprived EEG and 45% would not repeat the EEG. If a recurrent seizure occurs within six, or after 12 or 24 months, 87%, 67% and 44% would respectively conclude that the patient has epilepsy, while 57%, 65% and 72% would request an EEG. When a patient experiences a recurrence while being treated with anti-epileptic drugs, 11% of the respondents would request an EEG. Twenty-five percent would request an EEG before stopping medication after two years of remission. CONCLUSION The variability in neurologists' reported strategies about the use of EEG in the diagnosis of seizures is remarkably large. Consequences for the individual patient may be significant, including treatment decisions and driving restrictions. The availability and use of more sensitive diagnostic methods may be necessary to enhance agreement between neurologists.