Abstracts

In cases of medically intractable epilepsy, invasive monitoring is used to further determine the localisation of epileptogenic tissue when a) the Scalp EEG does not adequately localise the epileptogenic area; b) When EEG and neuroimaging are non-concordant suggesting an abnormality in more than one region or c) when seizures arise from functionally important areas of the brain. We retrospectively audited the history of seizure control in patients initially approved for invasive recordings but in whom the procedure was unavoidably delayed or postponed. The Epilepsy Unit at Beaumont hospital houses the only epilepsy surgery programme in Ireland. A total of 11 patients were on a waiting list for invasive monitoring at our centre up to early 2002 when due to a large-scale redevelopment of the unit, the procedures could not be carried out. During the following 2-year hiatus, despite being approved for invasive monitoring, all eleven patients were managed medically. Using an audit of patient[apos]s clinical charts after close clinical supervision in the out-patient department and with telephone interviews for incomplete data, we recorded the seizure types, frequency and outcome after 2 years, as well as all pertinent clinical, neurophysiological and radiological data in this highly specific group. Of the 11 patients, we found 4 were seizure free for over a year; Two patients, although still having seizures, perceived their control as improved or acceptable; 3 patients had further minor improvements in seizure control. One patient continued to have seizures at the same rate and is now awaiting a device insertion. One patient was lost to follow-up. Among the reasons for improvement was optimisation of medication regime (including the introduction of leveteracetam in 3 of the 4 seizure free cases). There was no common clinical, historical or pathophysiological mechanism in the cases reviewed. This interesting group of patients allows for a serendipitous observation of the course of intractable seizures in patients who, were it not for the forced hiatus in invasive monitoring, might otherwise have had epilepsy surgery. The fact that more than half had enjoyed either a complete remission in seizures or a worthwhile reduction in attacks suggests the need to constantly re-configure new medications and drug optimisation regimes into any decision to proceed to invasive recordings. (Supported by Epilepsy Surgery Programme, Beaumont Hospital, Dublin, Ireland.)