Results of the Stimulation of the Mesial Frontal and Parietal Cortex in Man.
Abstract number :
2.174
Submission category :
Year :
2000
Submission ID :
2769
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Cassio Forster, Jose A Buratini, Meire Argentoni, Viviane B Ferreira, Arthur Cukiert, Elcio Machado, Leila Frayman, Alcione Sousa, Joaquim Vieira, Hosp Brigadeiro, Sao Paulo Sp, Brazil; Hosp Brigadeiro, Sao Paulo Sp, Brazil.
RATIONALE: The physiology of the mesial frontal and parietal cortex is very poorly understood in man. This study reports our findings after stimulation of the mesial cortex by means of implanted subdural electrodes during the presurgical evaluation of epileptic patients. METHODS: Four patients with mesial frontal or supplementary area (SMA)seizures who had normal MRIs were studied. They were submitted to bilateral subdural electrodes implantation, covering both frontoparietal convexity and mesial regions. Cortical stimulation was carried out with square pulses of 0,1 msec of duration, 100 Hz and current ranging from 4-8 mA. RESULTS: Results obtained in Patient I (hypermotor seizures localized to the right mesial pre-SMA cortex) and Patient II (right SMA seizures with head deviation to the left) were similar: Left SMA (lSMA)- SMA posturing with head deviation to the right; Right SMA (rSMA)- SMA posturing with head rotation to the left; Mesial rolandic (MesRol)- contralateral clonic leg movements and bilateral mesial parietal (MP) without clinical phenomenology. Patient III had right SMA seizures with head rotation to the right. Stimulation results were as follows: lSMA- SMA posturing with head rotation to the right; rSMA- SMA posturing with head rotation also to the right; MR- contralateral clonic leg movements; lMP- SMA posturing and head turning to the right without clonic movements of the leg; rMP- no clinical phenomenology. Patient IV had left SMA seizures with head rotation to the left. Cortical stimulation results were as follows: lSMA- SMA posturing with head rotation to the right; rSMA- SMA posturing with head rotation to the left; MR: contralateral clonic leg movements; lMP- no clinical phenomenology; rMP- SMA posturing with head rotation to the left with clonic leg movements. CONCLUSIONS: In this series, the head's rotation direction was not useful in defining the side of the mesial foci. Furthermore, stimulation of the mesial parietal regions led to SMA-type posturing in 50% of the patients. The results of stimulation in Patients III and IV also suggested that both had symptomatogenic areas contralateral to the actual focus.