Measuring electronic signals on the surface of the brain helps neurosurgeons during surgery for epilepsy. The brain mapping system known as electrocorticography can determine the limits of the epileptogenic zones in the brain enabling only affected brain tissue to be removed during surgery. This is what Cyrille Ferrier, junior clinical neurophysiologist of the University Medical Center Utrecht (UMC) says in his doctoral thesis.
Ferrier investigated epilepsy patients with a localized predisposition disorder, an anomaly in the brain that occurs during its development. This form of frontal lobe epilepsy can be difficult to detect by an MRI scan and the extent of the disorder cannot always be determined like this. This makes it difficult for neurosurgeons to know exactly which part of the brain is affected.
Electrocorticography is the practice of placing an electrode directly on the exposed brain surface during surgery, in order to record electrical discharge patterns from the brain cells. The patterns change when the brain contains an anomaly. This enables the neurophysiologist and the surgeon to estimate during surgery whether there is a localized predisposition to epilepsy and its extent. When, following the intervention, the disturbed discharge patterns have disappeared, the operation can be finished. This method enables the removal of as little brain tissue as possible.
In the UMC, one to two people per week are operated on for epilepsy that cannot be treated with drugs. Most cases of epilepsy are caused by a defect in the frontal lobe which is relatively easy to detect by MRI scan. In difficult cases, electrocorticography may be necessary in order to detect the defect. The demand for this kind of treatment for the disorder is increasing. This is due to the continuing improvement in MRI-scanners meaning that more patients are eligible for surgical treatment of epilepsy.
Cyrille Ferrier will obtain his doctorate on November 28, from the University of Utrecht.
For more information please contact: University Medical Center Utrecht, department of internal and external communication, Annette Aarts and Linda Minnen, tel. 088 75 574 83.