Decisions after first seizure.

The probability of an intracerebral neoplasm occurring in patients presenting with first seizure was calculated using the data provided by four recent studies. After recording the history of the patients and performing clinical neurological examinations, the probability of a neoplasm was increased or reduced substantially, allowing rational decision to be made for further investigation or follow-up. The impact of conventional EEG on the probabilities was weak. Decision analysis can be used to improve diagnostic practices.