BOSTON - Noninvasive electrical brain stimulation offers hope as a potential new tool to ease the symptoms of certain diseases and mental illnesses. But neuroscientists from Beth Israel Deaconess Medical Center (BIDMC) and the Perelman School of Medicine at the University of Pennsylvania (Penn) are warning against self-administered brain stimulation by so-called "do-it-yourself" (DIY) users. Their "Open Letter" appears in the July 7 issue of Annals of Neurology.
"There is much about noninvasive brain stimulation that remains unknown," said corresponding author Michael D. Fox, MD, PhD, Associate Director of the Deep Brain Stimulation Program and the Associate Director of the Berenson-Allen Center for Noninvasive Brain Stimulation at BIDMC and an Assistant Professor of Neurology at Harvard Medical School. "Some risks, such as burns to the skin, are well recognized. However, other potential problems may not be immediately apparent. As neuroscientists we perceive an ethical obligation to draw the attention of both professionals and DIY users to some of these issues."
Cognitive neuroscience research suggests that electrical stimulation of the brain via electrodes applied to the scalp - known as transcranial direct current stimulation (tDCS) - can enhance cognition and relieve symptoms of anxiety, depression and other conditions. Because tDCS devices can be easily made with simple parts and tools, its in-home practice has grown in popularity among lay people seeking alternatives to drugs for depression and attention deficit disorder or just hoping to boost their memory, focus and creativity.
"Published results of these studies might lead DIY users to believe that they can achieve the same results if they mimic the research studies. However, there are many reasons why this simply isn't true," said first author Rachel Wurzman, PhD, a postdoctoral research fellow in the Laboratory for Cognition and Neural Stimulation at Penn. "Outcomes of tDCS can be unpredictable, and we know that in some cases tDCS use can actually make brain function worse."
Signed by 39 researchers who share these concerns, the "Open Letter" letter details the scientific reasons to exercise extreme caution in applying tDCS outside the lab.
Because so much remains unknown about the practice, do-it-yourself tDCS could result in unintended consequences, the researchers warn. Stimulation extends well beyond the regions beneath the electrodes, meaning DIY users could be targeting more of the brain then they intended. Moreover, it's not known how stimulation in one area may affect connected brain networks - or vice versa. In addition, what a person does before and during tDCS - for example, reading, sleeping, solving puzzles - can change its outcomes.
The researchers add that they haven't tested tDCS at the frequencies many home users report, such as stimulating daily for months or longer. "We know that stimulation from a few sessions can be quite lasting, but we do not yet know whether such changes are reversible, and the possible risks of a larger cumulative dose over several years or a lifetime have not been studied," they wrote.
Small changes in tDCS settings, including the current's amplitude, stimulation duration and electrode placement, can also have large and unexpected consequences. For example, a lay user might expect increasing the duration from 10 to 20 minutes to double the effects. In fact, it can produce the opposite change in brain function. "More stimulation is not necessarily better," the authors wrote.
Finally, factors such as age, gender, handedness, medication, even differences in head anatomy, could impact and potentially reverse an intended tDCS effect. The group cites previous findings that up to 30 percent of experimental subjects responded with changes in brain excitability in the opposite direction from other subjects using identical tDCS settings.
The researchers stress that, at this time, too little is known about tDCS for otherwise healthy people to assume the risks of DIY use. "In sum, it is important to know that whatever brain changes occur may be long-lasting, for better or worse," the authors warn.
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About Beth Israel Deaconess Medical Center
Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School and consistently ranks as a national leader among independent hospitals in National Institutes of Health funding.
BIDMC is in the community with Beth Israel Deaconess Hospital-Milton, Beth Israel Deaconess Hospital-Needham, Beth Israel Deaconess Hospital-Plymouth, Anna Jaques Hospital, Cambridge Health Alliance, Lawrence General Hospital, Signature Healthcare, Beth Israel Deaconess HealthCare, Community Care Alliance and Atrius Health. BIDMC is also clinically affiliated with the Joslin Diabetes Center and Hebrew Rehabilitation Center and is a research partner of Dana-Farber/Harvard Cancer Center and the Jackson Laboratory. BIDMC is the official hospital of the Boston Red Sox. For more information, visit http://www.bidmc.org.
Journal
Annals of Neurology