After just one session of transcranial stimulation (rTMS), a non-invasive brain stimulation treatment, patients with anorexia nervosa experienced a reduction in core symptoms, according to new research at King’s College London.
“We found that one session of rTMS reduced the urge to restrict food intake, levels of feeling full, and levels of feeling fat, as well as encouraging more prudent decision-making. Taken together, these findings suggest that brain stimulation may reduce symptoms of anorexia by improving cognitive control over compulsive features of the disorder,” said first author Dr. Jessica McClelland, Post-doctoral Researcher at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London.
In anorexia, successful outcomes are the exception, with only 20-30 percent of people recovering from the best available talking therapies. Up to 20 percent of people with anorexia die prematurely from the disorder. Given the urgent need to improve treatments, researchers are increasingly looking towards emerging neuroscience-based technologies that could target the underlying neural basis of anorexia.
“With rTMS we targeted the dorsolateral prefrontal cortex, an area of the brain thought to be involved in some of the self-regulation difficulties associated with anorexia,” said McClelland. “This technique alters neural activity by delivering magnetic pulses to specific regions of the brain, which feels like a gentle tapping sensation on the side of the head.”
For the study, 49 people participated in food exposure and decision-making experiments, both before and after a session of either real or placebo rTMS. Anorexia symptoms were measured immediately before and after receiving rTMS, as well as 20 minutes and 24 hours after the session.
The food exposure experiment was designed to test anorexia symptoms by asking participants to watch a two-minute film of people eating appetizing foods, such as chocolate and potato chips, while the same items were in front of them. They then had to rate the perceived smell, taste, appearance, and urge to eat these foods.
For the decision-making experiment, participants were asked to choose between a smaller, variable amount of money to be received immediately or a larger, fixed amount to be received after four different time points (a week, month, year, or two years).
Compared to the placebo group, the rTMS patients were more likely to make a prudent decision regarding the money — that is, they waited for larger, later rewards (i.e. delayed gratification), rather than choosing the more impulsive smaller, immediate option.
While the study was fairly small, the researchers note that there was a clear improvement in symptoms and decision-making abilities following just one session of rTMS. It is likely that with a larger sample and multiple sessions of rTMS these effects would be even stronger.
“Anorexia nervosa is thought to affect up to 4 percent of women in their life-time. With increasing illness duration, anorexia becomes entrenched in the brain and increasingly difficult to treat. Our preliminary findings support the potential of novel brain-directed treatments for anorexia, which are desperately needed,” said senior author Professor Ulrike Schmidt from the IoPPN at King’s College London.
“Given the promising findings from this study, we are now assessing whether rTMS has longer-lasting therapeutic benefits in a world-first clinical trial of rTMS treatment, involving 20 rTMS sessions, in people with anorexia nervosa.”
The findings are published in the journal PLOS ONE.
Source: King’s College London