-
-
Serial Vagus Nerve Stimulation Functional MRI in
Treatment-Resistant Depression.
- Nahas Z,
- Teneback C,
- Chae JH,
- Mu Q,
- Molnar C,
- Kozel FA,
- Walker J,
- Anderson B,
- Koola J,
- Kose S,
- Lomarev M,
- Bohning DE,
- George MS.
[1] 1Department of Psychiatry, Brain
Stimulation
Laboratory, Mood Disorders Program, Institute of Psychiatry,
Charleston, SC, USA [2] 2Department of Radiology, Radiology and Center
for Advanced Imaging Research, Medical University of South Carolina,
Charleston, SC, USA.
Vagus nerve stimulation (VNS) therapy
has shown
antidepressant effects in open acute and long-term studies of
treatment-resistant major depression. Mechanisms of action are not
fully understood, although clinical data suggest slower onset
therapeutic benefit than conventional psychotropic interventions. We
set out to map brain systems activated by VNS and to identify serial
brain functional correlates of antidepressant treatment and symptomatic
response. Nine adults, satisfying DSM-IV criteria for unipolar or
bipolar disorder, severe depressed type, were implanted with adjunctive
VNS therapy (MRI-compatible technique) and enrolled in a 3-month,
double-blind, placebo-controlled, serial-interleaved VNS/functional MRI
(fMRI) study and open 20-month follow-up. A multiple regression mixed
model with blood oxygenation level dependent (BOLD) signal as the
dependent variable revealed that over time, VNS therapy was associated
with ventro-medial prefrontal cortex deactivation. Controlling for
other variables, acute VNS produced greater right insula activation
among the participants with a greater degree of depression. These
results suggest that similar to other antidepressant treatments, BOLD
deactivation in the ventro-medial prefrontal cortex correlates with the
antidepressant response to VNS therapy. The increased acute VNS insula
effects among actively depressed participants may also account for the
lower dosing observed in VNS clinical trials of depression compared
with epilepsy. Future interleaved VNS/fMRI studies to confirm these
findings and further clarify the regional neurobiological effects of
VNS.Neuropsychopharmacology advance online publication, 3 January 2007;
doi:10.1038/sj.npp.1301288.
PMID: 17203016 [PubMed - as supplied by
publisher]
-
Related Links