International Neuromodulation Society Meeting Attendees Discuss New Therapies

by James Cavuoto editor

More than 500 clinicians, engineers, and researchers attended the 8th World Congress of the International Neuromodulation Society and 11th annual meeting of the North American Neuromodulation Society held in Acapulco, Mexico earlier this month. During the scientific program, numerous presenters discussed new neuromodulation therapies for treating disorders ranging from anxiety and Tourette syndrome to tinnitus and addiction.

The three dominant players in the neuromodulation industry, Medtronic, Boston Scientific, and St. Jude Medical, had a major presence at the meeting. Also on hand were representatives of several newer and startup neurotech firms, including Northstar Neuroscience, which is developing a cortical stimulation system to treat stroke and other disorders, Intelect Medical, which will be targeting the traumatic brain injury market with a DBS system, and Victhom Human Bionics, a Canadian firm that is developing an implanted foot drop stimulator.

In a pre-conference session devoted to commercialization issues chaired by Chris Coburn of the Cleveland Clinic, neurotech entrepreneurs John Bowers from Northstar Neuroscience and Ben Pless, formerly of NeuroPace, shared their experiences bringing neuromodulation therapies to market. Coburn related his observations from the Cleveland Clinic, which has spun off 22 companies over the last five years. He cited several factors that would influence a neurotech startup’s market potential, such as identifying the regulatory pathway, any predicate devices that exist, and the revenue potential for potential investors.

Bowers cited several factors that would be critical for the growth of the industry, including reaching out to the “influential implanters” and pushing reimbursement based on quality of life improvements, rather than mortality. Pless provided an overview of patent-related issues affecting neuromodulation devices. He noted that there have been 2000 issued patents for neuromodulation devices, most of them involving the peripheral nervous system. And while there has been little litigation in the neuro device space so far, Pless cautioned that that could change and cited several examples of major lawsuits in other medical device categories. Ali Rezai from the Cleveland Clinic addressed some of the conflict-of-interest issues that neuromodulation researchers and start-up firms might confront.

Though much of the scientific program at the 2007 event featured clinical and research results, several executives from neurotechnology firms made presentations. Rob Greenberg from Second Sight gave an update on his company’s Argus II retinal implant. The new device, which features 60 electrodes and new materials to accommodate higher charge density, will be tested in six users in the U.S., three in Europe, and two in Latin America. Andy Hoffer, the founder of Neurostream and now affiliated with Victhom Human Bionics, gave a historical overview of foot-drop stimulation systems, including surface-based, semi-implanted, and Victhom’s new fully implanted Neurostep system.

Ross Davis, a neurosurgeon who has been working with the Alfred Mann Foundation, described results from a trial of multiple Bion microstimulators implanted in the upper extremity of stroke patients. He said that electrical stimulation may play a significant role in the recovery of upper limb function. Seven participants (three females and four males) with post-stroke arm weakness and spasticity received implants on selected branches of their radial nerve/motor-points.
The study was performed at Southampton University in the UK. The participants received programmed stimulation to help them extend their elbows, wrists, and fingers in order to augment functional activities for at least one hour a day, five days a week, for 12 weeks. The patients had a mean age of 45 years and their strokes occurred an average of 3.9 years prior to treatment.

The study demonstrated a mean improvement across all patients in all outcome measures as well as feasibility and safety of using implanted microstimulators in post-stroke rehabilitation. No infections or failed devices were reported. The greatest functional improvement was demonstrated in the three participants whose stroke occurred within the past two years, suggesting that earlier intervention may be beneficial to rehabilitation. After 12 weeks of programmed stimulation, four of the seven participants could complete daily tasks without supplemental stimulation.

Bomin Sun, director and professor of the Center of Functional Neurosurgery at Shanghai Jiao Tong University Rui Jin Hospital, China, presented the results of a more than two-year study of DBS for the treatment of anorexia nervosa and related conditions. The trial included 20 patients whose previous psychiatric and pharmaceutical therapies had been ineffective. Two months following DBS treatment, anorexic patients gained between 17 and 44 pounds, and many saw significant improvement in obsessive-compulsive and anxiety symptoms.

Sun and colleagues implanted electrodes via a minimally invasive surgery in 15 patients, and used the DBS electrodes to stimulate the nucleus accumbens, a similar approach used for treating Parkinson disease. Twelve of these patients received radiothermal lesions (capsulotomy) targeted at the anterior internal capsule in addition to the DBS. While the pre-operation PET scans displayed a significant increase in metabolic levels, the post-operation PET scans demonstrated an immediate decrease in metabolic levels in all the patients.

All patients were followed for two to 26 months following treatment. Patients who underwent the capsulotomy combined with DBS showed significant improvement both in eating behavior and psychiatric symptoms. Three patients that received only DBS showed an improvement in obsessive-compulsive and anxiety symptoms, but minimal progress in eating behavior.