Abstracts

RATIONALE: During assessment for epilepsy surgery, patients undergo many costly and time-consuming tests and more recently the necessity to record ictal electrographic and clinical features has been questioned in some of the conditions amenable to surgery. We retrospectively reviewed our practice to see if useful information was obtained in the group of patients with unilateral hippocampal sclerosis (HS). METHODS: From 400 consecutive patients who entered the surgical program after January 1995 there were 191 patients with unilateral HS, identified on high resolution magnetic resonance imaging (MRI). All patients underwent continuous video-EEG telemetry (mean duration of recording 119 hours) with a minimum of 20 channels of EEG. RESULTS: Following scalp telemetry, surgery was recommended in 128/191 (67%). It was deferred in 37 patients for various reasons including improved seizure control and alternative management strategies. 26 patients remained. 11/26 had intracranial studies because of apparently discordant scalp findings, in 9 of these patients subsequent intracranial findings were concordant with the MRI. 3/26 patients had non-epileptic attacks and did not proceed; 1 patient died pending further investigations and 2 were rejected because of psychiatric issues. Only 9 were rejected solely on the basis of the scalp telemetry with extratemporal electroclinical features. CONCLUSIONS: In our experience video-EEG telemetry provides useful information in a decreasing proportion of patients with unilateral HS undergoing a surgical assessment. In this group, increasing dependence on MRI findings and the development of algorithms, based on clinical seizure type and other non-invasive assessments should be able to predict those patients who are likely to be rejected as surgical candidates, and may mean that in the future ictal recordings can be avoided.