Vagus Nerve Stimulation in GAERS: Results of a Pilot Study.
Abstract number :
3.020
Submission category :
Year :
2001
Submission ID :
1649
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
S. Dedeurwaerdere, Biology, Ghent University Hospital, Gent, Belgium; K. Vonck, MD, Neurology, Ghent University Hospital, Gent, Belgium; M. D[ssquote]have, MSc, Neurology, Ghent University Hospital, Gent, Belgium; D. Naritoku, MD, PhD, Neurology, Universi
RATIONALE: Vagus nerve stimulation (VNS) is a neurophysiological treatment for partial seizures with or without secondary generalization. There is no evidence from animal experiments or findings in humans about the efficacy of VNS in genetic primary generalized epilepsy.
METHODS: Eight GAERS were implanted with 5 EEG epidural peg electrodes and a stimulation electrode around the left vagus nerve and underwent long-term video-EEG monitoring. Six were stimulated 3 hours a day during 5 consecutive days with standard stimulation parameters (output current: 1.5mA, frequency: 30Hz, pulse width: 500 msec, on/off: 30s/5min). Two control GAERS underwent the implantation of recording and stimulation electrodes but were not stimulated. On day 2 and 5 of stimulation the number, duration and frequency of spike and wave discharges (SWD) were compared between the first hour of baseline EEG preceding stimulation and the last hour of stimulation.
RESULTS: In stimulated GAERS, average number per hour, duration and frequency of SWD in baseline conditions was 101 (SD=94), 8 sec (SD=6.5) and 9 Hz (SD=0.9) respectively. During the last hour of VNS the average number of SWD per hour, duration and frequency was 72 (SD=38), 9.7 sec (SD=8.2) and 9 Hz (SD=1.0). In baseline conditions, control rats had an average of SWD per hour of 93. The average duration and frequency were 7.5 sec and 8.5 Hz respectively. During the last hour of the fifth (non-stimulation) day, these figures were 69 SWD per hour, 6.5 sec and 8 Hz. When control GAERS versus stimulated GAERS and baseline versus five-day stimulation conditions were compared, no statistically significant differences could be found.
CONCLUSIONS: VNS delivered according to a five day - 3 hours per day - protocol has no significant influence on the number, duration and frequency of SWD in GAERS. Further studies using chronic continuous VNS will be necessary to elucidate the role of VNS in this model of primary generalized epilepsy.
Support: Funded by a grant from the F.W.O.-Flanders and the Ghent University Hospital Clinical Epilepsy Grant 1999-2001.