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Brain stimulation may reduce anorexia symptoms (2016-03-29)
Core symptoms of anorexia nervosa, including the
urge to restrict food intake and feeling fat, are
reduced after just one session of a non-invasive
brain Transcranial Magnetic Stimulation technique,
according to King’s College London research
published today in PLOS ONE.
This new study is the first randomised control trial
to assess whether high-frequency repetitive
transcranial magnetic stimulation (rTMS), already an
approved treatment for depression, is also effective
in reducing symptoms of anorexia.
Up to 20 per cent of people with anorexia die
prematurely from the disorder and treatments in
adults are moderately effective, with only 20-30 per
cent of people recovering from the best available
talking therapies.
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.
Dr Jessica McClelland, Post-doctoral Researcher at
the Institute of Psychiatry, Psychology &
Neuroscience (IoPPN), King’s College London, and
first author of the study, said: ‘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. 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.
‘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.’
In the study, 49 people completed food exposure and
decision-making tasks, both before and after a
session of either real or placebo rTMS. Symptoms of
anorexia were measured immediately prior to and
following rTMS, as well as 20 minutes and 24 hours
after the session.
The food exposure task sought to provoke anorexia
symptoms by asking participants to watch a
two-minute film of people eating appetising food,
such as chocolate and crisps, 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 task participants had to
choose between a smaller, variable amount of money
(£0-£100) available immediately and a larger, fixed
amount (£100) available after four different time
points (a week, month, year or two years).
Compared to the placebo group, they found that
participants who had real rTMS showed a tendency for
more prudent decision-making - that is, they waited
for larger, later rewards (i.e. delayed
gratification), rather than choosing the more
impulsive smaller, sooner option.
The study authors point out that although these
findings were only a statistical trend, there is 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.
Professor Ulrike Schmidt, senior author of the
study, from the IoPPN at King’s College London,
added: ‘Anorexia nervosa is thought to affect up to
4 per cent 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.
‘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.’
This study represents independent research
part-funded by the National Institute for Health
Research (NIHR) Biomedical Research Centre (BRC) at
South London and Maudsley NHS Foundation Trust and
King’s College London.
The IoPPN’s Eating Disorders Research Group at
King’s College London is currently recruiting for a
longer-term study of rTMS to examine the neural
mechanisms underlying the effects of rTMS. Find out
more about the TIARA study: Transcranial magnetic
stimulation and Imaging in AnoRexia nervosa (Link...).
See also
Paralyzed Men Gain Movement Without Surgery
(2015-08-12) Link...
Brain stimulation limits calories consumed in adults
with obesity (2015-11-05) Link...
For more information
PLOS ONE
A Randomised Controlled Trial of Neuronavigated
Repetitive Transcranial Magnetic Stimulation (rTMS)
in Anorexia Nervosa
DOI: 10.1371/journal.pone.0148606 Link...