Address for correspondence: Russell J. Andrews, M.D., 555 Knowles Drive, Suite 112, Los Gatos, CA 95032, USA. Voice: 408-374-0401; fax: 408-866-8842.
rja{at}russelljandrews.org
Ann. N.Y. Acad. Sci. 993: 1-13 (2003).
Neuromodulation denotes controlled electrical stimulation of
the central or peripheral nervous system. The three forms of
neuromodulation described in this paper—deep brain stimulation,
vagus nerve stimulation, and transcranial magnetic stimulation—were
chosen primarily for their demonstrated or potential clinical
usefulness. Deep brain stimulation is a completely implanted
technique for improving movement disorders, such as Parkinson's
disease, by very focal electrical stimulation of the brain—a
technique that employs well-established hardware (electrode
and pulse generator/battery). Vagus nerve stimulation is similar
to deep brain stimulation in being well-established (for the
treatment of refractory epilepsy), completely implanted, and
having hardware that can be considered
standard at the present
time. Vagus nerve stimulation differs from deep brain stimulation,
however, in that afferent stimulation of the vagus nerve results
in diffuse effects on many regions throughout the brain. Although
use of deep brain stimulation for applications beyond movement
disorders will no doubt involve placing the stimulating electrode(s)
in regions other than the thalamus, subthalamus, or globus pallidus,
the use of vagus nerve stimulation for applications beyond epilepsy—for
example, depression and eating disorders—is unlikely to
require altering the hardware significantly (although stimulation
protocols may differ). Transcranial magnetic stimulation is
an example of an external or non-implanted, intermittent (at
least given the current state of the hardware) stimulation technique,
the clinical value of which for neuromodulation and neuroprotection
remains to be determined.
