Acute vagus nerve stimulation using different pulse widths produces varying brain effects
Received 17 September 2003; received in revised form 1 December 2003; accepted 3 December 2003.
Abstract
Background
Vagus nerve stimulation (VNS) is an approved treatment for epilepsy and has been investigated in clinical trials of depression. Little is known about the relationship of VNS parameters to brain function. Using the interleaved VNS /functional magnetic resonance imaging (fMRI) technique, we tested whether variations of VNS pulse width (PW) would produce different immediate brain activation in a manner consistent with single neuron PW studies.
Methods
Twelve adult patients with major depression, treated with VNS, underwent three consecutive VNS/fMRI scans, each randomly using one of three PWs (130 μs, 250 μs, or 500 μs). The data were analyzed with SPM2.
Results
Global activations induced by PWs 250 and 500 were both significantly greater than that induced by PW 130 but not significantly different from each other. For global deactivation, PWs 130 and 250 were both significantly greater than PW 500 but not significantly different from each other. Regional similarities and differences were also seen with the various PWs.
Conclusions
The data confirm our hypothesis that VNS at PW 500 globally produces no more activation than does PW 250, and PW 130 is insufficient for activation of some regions. These data suggest that PW is an important variable in producing VNS brain effects.
aCenter for Advanced Imaging (QM, DEB, ZN, JW, KAJ, SD, ML, PM, J-HC, MSG), Medical University of South Carolina, Charleston, South Carolina, USA
bBrain Stimulation Laboratory (QM, ZN, BA, KAJ, J-HC, MSG), Medical University of South Carolina, Charleston, South Carolina, USA
cDepartment of Radiology (DEB, JW, SD, ML, MSG), Medical University of South Carolina, Charleston, South Carolina, USA
dRalph H. Johnson Veterans Affairs Medical Center (MSG), Charleston, South Carolina, USA
Address reprint requests to Qiwen Mu, M.D., Ph.D., Brain Stimulation Laboratory, Medical University of South Carolina, Institute of Psychiatry, 502 N, 67 President Street, Charleston SC 29425, USA.
ABSTRACT