Can a New Medical Device Help Treat ADHD?
New research examines the prospects for nerve stimulation and neuro-modulation.
Posted Apr 23, 2019
With one in seven American children and teens now diagnosed with attention-deficit/hyperactivity disorder (ADHD) and psychostimulant medication (amphetamines such as Ritalin and Adderall) commonly used to treat the condition, often generating a range of adverse effects, the demand for alternative treatments has surged in recent years.
Mindful of that need, last Friday the FDA approved the first non-drug device to treat the disorder. Aimed at children aged 7 to 12, the prescription-only device—called the Monarch external Trigeminal Nerve Stimulation (eTNS) System—is described in an agency press release as “innovative, safe, and effective” in treating children who have difficulty staying focused and paying attention, two of the key criteria listed for a diagnosis of ADHD.
The size of a cell-phone, the device sends a low-level electrical pulse to the parts of the brain thought to be involved in “selective maintenance of attention.” Through a small patch that adheres to the forehead, just above the eyebrows, the device emits a signal that produces a “tingling sensation on the skin.”
“While the exact mechanism of eTNS is not yet known,” the FDA acknowledges, “neuroimaging studies have shown that eTNS increases activity in the brain regions that are known to be important in regulating attention, emotion, and behavior.”
The agency approved the device on the basis of a single pilot study appearing this month in the Journal of the American Academy of Child & Adolescent Psychiatry, with findings that also are far from conclusive. Involving 62 children aged 8 to 12 years who were administered active or placebo TNS nightly during sleep for four weeks, the study determined that “only slightly more than half of those receiving therapy” experienced “clinically meaningful improvement.”
Led by James J. McGough at UCLA, the researchers found that “significant increases in weight and pulse were seen with active compared with sham [placebo] TNS over 4 weeks…with notable increases in fatigue, headache, and increased appetite with active TNS.” Raising concerns about longer-term use, efficacy, and adverse effects, as well as the number of “non-medication ADHD treatments [that] are biased toward false positive findings,” the study noted that changes in the active group were “not readily explained and require ongoing investigation.”
One of McGough’s co-authors continued to represent the management team of the device-maker under review (NeuroSigma, Inc.), his COI disclosure also indicating that he had been “allocated stock options” in the company. (I have reached out to them for comment and will update if they respond.) Just as question-raising are the prospects for practical implementation after a month-long investigation, not least when the study authors concede that similar non-medication treatments to ADHD, such as electroencephalography (EEG)-based neurofeedback and noninvasive brain stimulation methods, “have largely failed to demonstrate positive effects.”
One of the meta-analyses they cite, published three years earlier in the Journal of the American Academy of Children & Adolescent Psychiatry (June 2016), examined 13 such randomized trials involving in total a much-larger 520 participants. It too determined that “evidence from well-controlled trials with probably blinded outcomes currently fails to support neurofeedback as an effective treatment for ADHD.” Just as important, it urged that “future efforts…focus on implementing standard…protocols, ensuring learning and optimizing clinical relevant transfer”—aspects that the recent, 62-person study failed to establish.
“At a mechanistic level,” McGough and co-authors wrote earlier this month, “TNS is believed to stimulate the nucleus tractus solitarius, which relays signals” to other parts of the brain. But what they actually tested through such activation was the extent to which DSM-5-listed symptoms—the ADHD Rating Scale—diminished in intensity, not whether the children who managed to sleep with the device for four weeks showed practical improvements in concentration, learning, and self-control. Almost as significant, the children given a sham/placebo pulse indicated a significant drop in the ADHD Rating Scale as well, though by smaller increments (33.7 to 27.5 points [placebo], versus 34.1 to 23.4 points in the active device group), indicating a placebo effect almost as powerful.
As the authors of the June 2016 meta-analysis earlier observed, “The rationale for the use of neurofeedback for ADHD rests on the idea that promoting normalization or self-regulation of brain activity will translate into improved cognitive and behavioral control.” But with the recent FDA approval, that outcome remains uncertain and as yet unknown. Parents and physicians may instead see “increases in weight and reported appetite” in children given the devices, as well as statistically significant increases in drowsiness, trouble sleeping, teeth clenching, headache, and fatigue.
With medical insurers currently declining to cover such treatment, given the costs, parents interested in non-stimulant treatment for ADHD arguably face a tough decision over whether to purchase a device whose sole study has found that “only slightly more than half of those receiving therapy have clinically meaningful improvement.” They may reasonably wonder whether a careful review of diet and exercise—including sugar- and caffeine-intake—wouldn’t yield more immediate results at a fraction of the cost.
Above all, they may wish to double-check whether the ADHD diagnosis—already “prone to overrate male externalizing behavior,” according to researchers—is in fact accurate. According to the authors of 2017 study in Child and Adolescent Psychiatry and Mental Health, discussed earlier on this blog, children born close to kindergarten or school cut-off dates are 30 percent to 60 percent more likely to be diagnosed with ADHD. As such, they are likely to receive psychostimulants such as Ritalin “twice as often as children born only a few days later, but after the cut-off date.” Adjusted to figures representing the U.S. population, the 2017 study authors determined, “approximately 1.1 million children received an inappropriate diagnosis [of ADHD] and over 800,000 received stimulant medication due only to relative [im]maturity.”
Cortese S, Ferrn M, Brandeis D, et al. (2016) “Neurofeedback for attention-deficit/hyperactivity disorder: meta-analysis of clinical and neuropsychological outcomes from randomized controlled trials.” J Am Acad Child Adolesc Psychiatry 55:444-55. [Link]
FDA News Release (2019). “FDA permits marketing of first medical device for treatment of ADHD.” April 19. [Link]
McGough J, Sturm A, Cowen J, et al. (2019). “Double-Blind, Sham-Controlled, Pilot Study of Trigeminal Nerve Stimulation for Attention-Deficit/ Hyperactivity Disorder.” J Am Acad Child Adolesc Psychiatry 58.4:403–11. [Link]
Merten E. C., Cwik J. C., Margraf J., and Schneider S. (2017). “Overdiagnosis of mental disorders in children and adolescents (in developed countries).” Child and Adolescent Psychiatry and Mental Health 11:1. [Link]