When a patient with fibromyalgia is not responding to standard treatments, adding a noninvasive brain therapy might help them feel better.
Repetitive transcranial magnetic stimulation (rTMS) of the motor cortex might help reduce pain and improve functioning in fibromyalgia, according to new research published in the British Journal of Anaesthesia. The study was the first international randomized, double-blind, sham-controlled trial testing rTMS, which uses magnetic fields to stimulate the brain, as an add-on therapy for fibromyalgia.
“This is really promising because as our colleagues know, it is extremely complicated to treat these patients,” said Didier Bouhassira, MD, PhD, a co-author on the study. He is a research director at the French National Institute of Health and Medical Research and a neurologist and pain specialist at the Pain Assessment and Treatment Center at Ambroise Paré Hospital, Boulogne-Billancourt, France.
The Effects of rTMS in Fibromyalgia
The study included 101 women with fibromyalgia who were not improving with other treatments. Study participants received 10 sessions of rTMS targeting the primary motor cortex over 2 weeks, followed by weekly treatments for 6 weeks and treatments every other week for 8 more weeks. Each 15-minute session included 3000 electrical pulses at a frequency of 10 Hz.
Some patients received a sham treatment where the device did not emit magnetic fields. A blinding assessment confirmed patients were unable to guess which treatment they received.
Pain response was defined as a 50% or greater reduction in pain. At week 8, the probability that a higher proportion of participants responded in the rTMS group compared with the sham group was 99.4%. Relative pain reduction was higher in the rTMS group (40.4%) than in the sham group (18.4%). At week 16, the probability that a higher proportion of participants responded in the rTMS group compared with those in the sham group was just 34.2%. However, the probability of a greater reduction in the fibromyalgia impact questionnaire score, which measures functional improvements, in the rTMS group was 79.1%.
The treatment was safe, with no difference in adverse events between participants receiving TMS and sham treatment.
“This is a very important confirmation that it is safe, it is noninvasive, and it is clearly an alternative to the medical treatments in these patients, at least in fibromyalgia, probably also in other chronic pain patients, and we do know all the problems associated with the pharmacological treatments of pain, especially with opioids,” Bouhassira said.
Bouhassira said more research is needed to explain the mechanisms of action of rTMS. However, it might work on dysfunctional pain modulation systems in the brains of people with fibromyalgia. The target brain region, the primary motor cortex, connects with networks responsible for perceiving pain signals.
“Our main hypothesis is that with the magnetic field, with the rTMS, we are able to act on these systems and to improve the functioning and probably the connectivity of these systems,” he said.
rTMS might also affect the release of natural opioids in the brain to help relieve pain.
How Does This Study Compare to Previous Research?
Earlier, smaller studies of rTMS in fibromyalgia have had varying results on pain and quality of life. In 2020, a group of experts in Europe gave rTMS of the primary motor cortex a Level B recommendation for improving quality of life in fibromyalgia.
“The evidence is not great,” said Steven P. Cohen, MD, a professor of anesthesiology and neurology at Northwestern University, Chicago. He said larger follow-up studies with 250 or more patients would help clarify the effects of rTMS in fibromyalgia. However, Cohen sees why patients and doctors might be interested in noninvasive treatments targeting the brain in fibromyalgia.
“Conceptually, it’s very appealing to do some kind of stimulation in the brain where the problem is, rather than for peripheral conditions,” he said.
Which Patients With Fibromyalgia Are Most Likely to Respond?
In this study, patients who used opioid medications were less likely than others to benefit from rTMS. Bouhassira and collaborators are now studying clinical predictors of response to find which patients are most likely to respond. More research is also needed to uncover how long the effects of rTMS last and how often follow-up treatments should be delivered.
Bouhassira said that in his center, some patients with fibromyalgia or other chronic pain syndromes receive an rTMS protocol similar to the one the team evaluated in this paper. A subset — about 25%-30% — see effects lasting 3-5 months.
“This is extremely promising and encouraging, but of course, this will have to be confirmed in large international study, and also we will have to understand the mechanisms,” Bouhassira said. “How is it possible to maintain such long, lasting effects in these patients?”
Another question is patient access to treatment. rTMS is now approved by the US Food and Drug Administration for depression, cortical mapping, migraine with aura, and obsessive-compulsive disorder, but it can cost thousands of dollars.
“It’s really expensive,” Cohen said. “People have to go for many sessions.”
The therapy can require a time commitment of many hours over weeks or months, and it can be hard to fit into your schedule, Cohen said.
More research on clinical predictors to response might help doctors and patients weigh costs and benefits.
“If it is possible to maintain the effects, at least in good responders, with only three to four stimulation sessions per year, I can tell you that it is much less expensive than taking drugs every day during all this period,” Bouhassira said.
This study was partially funded by the Pain Center of the Department of Neurology at the University of São Paulo, CNPq (Brazilian National Council for Scientific and Technological Development), Teijin Pharma Limited, the Danish National Research Foundation, and MagVenture. MagVenture had no role in the study. Bouhassira had no relevant conflicts of interest to disclose. Cohen is on the Clinical Advisory Board for Sword Health.