Directing Magnetic Energy

Magnetic stimulation of the nervous system is a relatively new tool in the arsenal of clinicians and researchers working on neurological and psychiatric diseases and disorders. As we discuss in our article on magnetic stimulation and migraine research [link], this tool offers capabilities and characteristics not available with other neurotechnology tools. And nowhere are these advantages more pronounced than in the human brain, which has been largely inaccessible to researchers and clinicians alike. The ability to direct energy to the cerebral cortex so that induced currents can activate selected brain areas is exceptionally powerful, and one that we expect will grow in utility and popularity in the years ahead.

Of course magnetic stimulation still has a ways to go before it can become the general-purpose neurotechnology tool we would like it to become. First off, there is a good deal more research on the safety and efficacy of transcranial magnetic stimulation (TMS) as a tool or as a treatment for neurological and psychiatric disorders. There is also much more basic understanding of neurophysiology that we need. And there are a host of technological and product developments that are needed, including greater localization of stimulation, lesser energy demands, and more flexibility in stimulation parameters.

Still, TMS offers an appealing alternative to pharmacological and electrical stimulation approaches to modulating brain function. Drugs and other compounds offer ease of access to the central nervous system but lack much specificity, except perhaps at the receptor or transmitter level. Implanted stimulation systems offer great specificity but at a much higher cost of access. Magnetic stimulation falls in the middle on both aspects: it’s more localizable than pharmaceutical action, and less invasive than most forms of electrical stimulation,

That raises in our mind the possibility of using TMS in concert with either pharmaceutical/cell-based therapies or with implanted electrical stimulators. Is it possible to expand the selectivity of drug treatment by synchronizing its time course of action with magnetic stimulation? Is it possible to fine-tune the activation of specific cortical centers by directing a magnetic field to an implanted lead, coil, or stimulator? We’ve already seen the value of combining magnetic stimulation with brain imaging tools such as fMRI in order to optimize the placement of coils during stimulation, an innovation offered in Magstim’s frameless image-guided system.

Whether TMS is used in conjunction with another modality, or as a treatment modality of its own, we hope that the manufacturers and users of the systems pursue relentlessly a greater understanding of the mechanisms of treating specific disorders, and not rely on the “it seems to work” mentality that governs other treatments such as electroconvulsive therapy, for instance. While building up efficacy data may help sell machines in a given market, the long-term picture will be brighter if researchers and clinicians are able to apply functional models from existing therapeutic regimens to as-yet undiscovered treatments using magnetic stimulation.

Having said that, we can’t help wonder why there aren’t more vendors active in the TMS market. Given the intense amount of competition that already exists in neurostimulation, magnetic stimulation seems to be a tool every neurotechnology player should have in their repertoire.

James Cavuoto
Editor and Publisher