THE RELATIONSHIP BETWEEN PAIRED PULSE MAGNETIC MEP AND PROGNOSIS IN EPILEPSY SURGERY
Abstract number :
1.124
Submission category :
Year :
2003
Submission ID :
3934
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Tohru Kamida, Hiroshi Baba, Minoru Fujiki, Tomonori Ono, Kenji Ono, Hidenori Kobayashi Neurosurgery, Oita Medical University, Hasama-machi, Oita, Japan; Neurosurgery, National Nagasaki Medical Center, Omura, Nagasaki, Japan; Yokoo Hospital, Isahaya, Nagas
To assess whether single and paired pulse transcranial magnetic stimulation (TMS) can predict prognosis in epilepsy surgery.
Motor evoked potentials (MEPs) of the unilateral hand muscles were recorded following single and paired pulse TMS of the motor cortex in both hemispheres using a circular coil. The interstimulus intervals of paired stimulation were 1-16 ms with the conditioning stimulus being 80% of the motor threshold. Subjects were 5 patients with temporal lobe epilepsy (TLE) with unilateral hippocampal sclerosis and 3 patients with myoclonic or head drop seizures. The former had tailored anterior temporal lobectomy. The latter received anterior callosotomy, resulting in unilateralization of epileptic discharges. In these cases, side of hemisphere showing unilateralized epileptic discharges were defined as affected one. The corticocortical inhibition and facilitation curve was drawn out with MEPs before and after surgery and the relationship between MEPs and surgical prognosis were investigated.
In 4 out of 5 patients with TLE whose surgical results were class I, the affected hemisphere showed cortical hyperexcitability before surgery and normal inhibitory and excitory state after surgery. Contrary, in a patient with class III, unaffected hemisphere showed cortical hyperexcitability before and after surgery. In callsotomy group, 2 patients with excellent outcome had the same results as TLE group with class I. Another patient with 50% reduction of seizures did not show cortical hyperexcitability before surgery.
The relationship between single and paired pulse TMS and surgical prognosis were indicated. This method can potentially predict postoperative outcome in epilepsy surgery.