Passing the Baton

Neuromodulation therapy delivered via deep brain stimulation is one of the most successful segments of the neurotechnology industry and offers tremendous potential for a host of new applications currently under development. But the product category is impacted by the surgical and post-surgical challenges of inserting and maintaining leads in the basal ganglia deep within the brain.

As we report in this issue, there are several lines of research that offer the promise of a much less invasive but viable brain neuromodulation therapy. Miguel Nicolelis’ team at Duke University has raised the possibility of using spinal cord stimulation to treat movement disorders [see Research Highlights, p5]. Karl Deisseroth’s team at Stanford has shown that optical stimulation of cortical axons might be as effective as current DBS systems [see Research Highlights, p5]. And conceivably, current work on trigeminal nerve stimulation may lead to a viable alternative to DBS to treat intractable epilepsy [see article, p1].

What these potential new therapies have in common is the exploitation of the nervous system’s innate connectivity as a means of delivering therapeutic stimulation to a target. This “indirect” form of neuromodulation may represent a better strategy for delivering stimulation if it is easier to implant a device and to modulate the relevant stimulation parameters. This in turn may translate into increased rates of patient adoption and clinician acceptance.

Of course, no one is suggesting that DBS systems will one day be obsolete even if these other forms of neuromodulation prove effective. We suspect that it will be beneficial for clinicians to have a range of therapies at their disposal for various neurological disorders and perhaps mate the degree of invasiveness of a device or therapy with the severity of a patient’s condition.

Also, it is important to remember that absent the relatively large population of users that have undergone DBS surgery, we would not know nearly as much as we do now about effective targets, likely circuits in the normal functioning brain, mechanisms of action, and optimal stimulation parameters. Whether therapeutic stimulation is ultimately delivered to the desired target directly via DBS, TMS, cortical stimulation, or surface stimulation—or indirectly via synaptic transmission over a well understood neural pathway—future patients will owe much to the generations of prior users, device engineers, neurosurgeons, and researchers who have preceded them.

James Cavuoto
Editor and Publisher