The Vagus Nerve Stimulator (VNS) has been researched for approximately 14 years. This
"pacemaker for the brain", acts as a stimulator for the vagus nerve. The vagus nerve is
defined as the nerve that produces inhibition of neural processes, which can alter the
brain electrical activity.
Medical treatment for depression has included over the years, neurosurgery,
electroconvulsive therapy, transcrainal magnetic stimulation, and anti-depressant
VNS was first considered for treatment-resistant depression because:
1. clinical observations of improved cognition and mood during studies of
patients with epilepsy .
2. the fact that several anti-convulsant medication are used to treat mood
The most common side effects that have been reported in research studies and clinical
trials as possibly, probably, or definitely related to stimulation were hoarseness,
throat pain, headache, shortness of breath, general pain, and neck pain.
In general, stimulation-related effects were mild and well tolerated, and they have
occurred only when stimulation was on. Hypomania has been caused through Vagus Nerve
Stimulation, but has subsided with stimulation reduction.
In research studies and clinical trials responses occurred between 1 and 10 weeks
following the initiation of stimulation.
For practicality all studies in humans, Vagus Nerve Stimulation refers to stimulation of
the left cervical vagus nerve using a commercial device.
In many ways, VNS is much like the very common practice of implanting cardiac
pacemakers. In both cases, a generator sends an electrical signal to an organ through an
Vagus Nerve Stimulation is delivered through an implantable, multiprogrammable, bipolar
pulse generator ( the size of a pocket watch) that is implanted in the left chest wall
to deliver electrical signals to the left vagus nerve through a bipolar lead. With VNS,
the electrode is wrapped around the vagus nerve in the neck, near the carotid artery
using a separate incision, and then connected to the generator.
The software, along with a personal computer, provide telemetric communication with the
pulse generator, which enables noninevasive programming, functional assessments and data
retrieval. The system includes mechanical and electrical safety features that minimise
the possibility of high-frequency stimulation that could lead to tissue damage. In
addition, each patient is given a magnet that, when held over the pulse generator, turns
off stimulation. When the magnet is removed, normal programmed stimulation resumes.
The possible side-effects that have been reported at some time during treatment that
were significantly increased, were voice alteration/hoarseness, cough, throat pain,
nonspecific pain, dyspnoea, paraesthesia, dyspepsia, vomiting and infection. No
cognitive, sedative, visual, affective, or coordination side effects have been
Jolted Out Of Major Depression By: Robert Davis, USA TODAY