Vagus Nerve Stimulation Induces Specific Neurochemical Changes in the Central Nervous System
Abstract number :
2.071
Submission category :
Year :
2000
Submission ID :
2454
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Erhan Ergene, William M Brooks, Jerry J Shih, Univ of New Mexico Sch of Medicine, Albuquerque, NM.
RATIONALE: Vagus nerve stimulation (VNS) is a novel therapy used in patients with medically intractable epilepsy. The mechanisms mediating the effects of VNS remain unknown. The vagus nerve contains afferent fibers projecting, via the brainstem, to limbic brain regions including the hippocampus and the insular cortex. We hypothesized that VNS may alter local tissue concentrations of neurochemicals in these regions. METHODS: We measured N-acetylaspartate (NAA), choline (Cho), and creatine/phosphocreatine (Cr) levels in the hippocampus and the insula using 1H magnetic resonance spectroscopy (1H-MRS) in patients treated with VNS and in control patients with epilepsy who were treated with antiepileptic drugs only. RESULTS: NAA/(Ch+Cr) ratio was significantly (p < 0.05) lower in the right insula of the VNS group compared to controls (see Figure). There was no significant difference in NAA, Cho, Cr and NAA/(Ch+Cr) ratios between the groups in other regions. CONCLUSIONS: VNS may have region-specific modulatory effects on local tissue concentrations of neurochemicals/metabolites, which may play a role in the anticonvulsant effects of the procedure.