A new therapy that electrically stimulates a major nerve in the brain shows promising results for relief of major depression. The treatment — trigeminal nerve stimulation (TNS) — reduced depression symptoms by an average of 70 percent during an eight-week study conducted at UCLA.
Major depression is a disabling brain condition resulting in depressed mood, negative effects on sleep, energy, decision-making and memory, and possible thoughts of death or suicide. The disorder affects 15 million adults in the U.S., and according to the World Health Organization, by 2020 it will be the second-largest contributor to disability in the world.
Although antidepressants have helped many people recover from major depression and resume their lives, there is only a 30 percent success rate for patients taking their first medication. If the first drug doesn’t work, patients typically continue trying a series of other antidepressants. Most of these medications have significant side effects, including obesity, sexual dysfunction, drowsiness, nausea and fatigue.
Dr. Ian A. Cook, the Miller Professor of Psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA and the study’s head investigator, presented the results at a recent National Institutes of Health conference on depression and other psychiatric disorders. There he noted that 80 percent of the subjects achieved remission with electrical stimulation, a significant statistic in this pilot study.
The stimulator used during the depression clinical trial was about the size of a large cell phone. Two wires from the stimulator were passed under the clothing and connected to electrodes attached to the forehead by adhesive. The electrodes transmitted an electrical current to the nerve. All the patients in the trial used the stimulator for about eight hours every night while they slept. In contrast to antidepressants, no major side effects were noted.
“The major branches of the trigeminal nerve in the face are located close to the surface of the skull and can be stimulated either with noninvasive external electrodes, as we used in this trial, or with minimally invasive subcutaneous electrodes,” said Cook.
He added that some patients may prefer to have miniature electrodes implanted under the skin rather than apply new electrodes daily.
Cook hypothesized that electrical stimulation of the trigeminal nerve generates a cascading sequence of events in the existing neuronal infrastructure. In essence, he said, “TNS provides a high-bandwidth pathway into the brain.”
TNS was originally pioneered at UCLA by Dr. Christopher M. DeGiorgio, professor of neurology, in order to help treatment-resistant epileptics. The results of a positive 12-patient feasibility trial in epilepsy were reported last year in the journal Neurology. A larger, double-blind pilot epilepsy clinical trial is underway at UCLA and the University of Southern California.
DeGiorgio was a co-principal researcher for the depression trial, and he explained that TNS is quite remarkable because it is capable of sending signals to key points deep in the brain without penetrating into the skull.
In an effort to bring TNS out of the laboratory and into patient care, UCLA’s Office of Intellectual Property recently achieved an exclusive worldwide license for the TNS with NeuroSigma, a Los Angeles-based neuromodulation company formed in 2008 to commercialize promising technologies created at research institutions and leading universities.
Source: University of California