RESUMEN
BACKGROUND: To improve the sensitivity of the EEG in the diagnosis and classification of seizures or epilepsy, long-term recording with inferior temporal electrodes are recommended. MATERIAL AND METHODS: The spatial distribution of epileptiform discharges from 24h EEG with 25 electrodes (10-20, extended by F9/F10, T9/T10, P9/P10) was retrospectively analyzed in 25 cases. RESULTS: Maximum negativity was located below the 10-20 electrodes in 84%. Epileptiform discharges were more clearly detected on inferior temporal electrodes in 64%. In the intention-to-test population of 77 patients the number needed to test with extra electrodes was estimated as 5. CONCLUSION: Recording EEG with 25 electrodes for 24â¯h improves the detection and localization of temporal epileptiform discharges also in geriatric patients with suspected nonlesional epilepsy.