EEG outside the hairline: detection of epileptiform abnormalities

We have assessed the reliability in 25 epileptic patients of EEG recording using disposable self-adhesive electrodes and a seven-channel extra-hairline montage, through comparison to simultaneous standard cable telemetry. Epileptiform abnormalities were detected in all patients on blind interpretation of data acquired using the novel technique. On comparison of specific epileptiform abnormalities identified blindly, a false positive rate of 10% and a false negative rate of 8% were encountered. Posterior temporal complexes accounted for most false negatives, and most false positives did not represent failings of the recording technique. We conclude that EEG recording outside the hairline with disposable electrodes represents a reliable means to acquire, quickly and simply, EEG evidence of epilepsy. As such, it may prove useful in the acute evaluation of patients presenting with apparent seizures.