Repetitive transcranial magnetic stimulation (rTMS) improved quality of life in patients with fibromyalgia, but did not have any effect on pain, according to a new study.
The randomized, double-blind, sham-controlled study, published online in Neurology March 26, was conducted by a group from Aix-Marseille Université, Marseille, France.
"This study showed that high-frequency rTMS over the left primary motor cortex had a delayed positive impact on patients' quality of life after 11 weeks of treatment, without effect on pain," senior author, Eric Guedj, MD, commented to Medscape Medical News. "rTMS may provide a safe and noninvasive complement to analgesics in some people with fibromyalgia."
Noting that this improvement was associated with a concomitant increase in right limbic metabolism, Professor Guedj said, "This argues for a neural substrate to the impact of rTMS on the emotional dimension of fibromyalgia, and for the possible modulation of brain areas to improve the symptoms."
Commenting on the study for Medscape Medical News, Daniel Clauw, MD, director of the Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, was surprised that the treatment did not affect pain, but said the results were in line with many other studies in fibromyalgia and other chronic pain states showing that cortical electrostimulatory therapies can be of some benefit.
"As we learn the precise locations to stimulate and appropriate dosages, these treatments will likely become more effective. Since these therapies all target the brain, this also helps confirm much of the pathology in conditions such as fibromyalgia is in the brain — not out in the periphery," he added.
Affective, Emotional, and Social Improvement
Professor Guedj explained that previous studies have shown individual resting-state brain functional abnormalities in patients with fibromyalgia, within cortical areas that are reachable by TMS. The present study aimed to demonstrate that it is possible to modulate these brain areas with TMS in order to correct functional brain abnormalities and improve symptoms.
For the study, 38 patients were randomly assigned to high-frequency rTMS (n = 19) or sham stimulation (n = 19) applied to the left primary motor cortex in 14 sessions over 10 weeks. The primary clinical outcomes were quality-of-life changes at the end of week 11.
These showed that patients who received the rTMS therapy had greater improvement in quality of life, particularly in affective (mood or feelings), emotional (joy, sadness, anger, anxiety), and social (work performance, participation in social activities, contact with friends, and engaging in hobbies and interests) areas.
The primary endpoint was change on the Fibromyalgia Impact Questionnaire (FIQ). At baseline, patients in the treatment group had an average score of 60 and the control group had an average score of 64 on this scale, where lower scores indicate better quality of life.
After 11 weeks, the average score of patients receiving the treatment had dropped by about 10 points, while the average score had increased by 2 points for those receiving the sham treatment.
TMS was also associated with a significant improvement on the mental component of the Short Form (SF)-36 quality-of-life score. No significant effect was found for other clinical outcomes.
Table. Quality of Life: Mean Change From Baseline
|Measure||Active TMS||Sham||P Value|
|SF-36 score (composite physical)|
|SF-36 score (composite mental)|
FIQ scores range from 0 to 100, with higher scores indicating more severe symptoms. SF-36 scores range from 0 to 100, with higher scores indicating better health status.
Patients also underwent positron emission tomographic neuroimaging, and results showed that compared with the sham stimulation group, patients in the active TMS group had an increase in right medial temporal metabolism between baseline and week 11, which correlated with FIQ and mental component SF-36 concomitant changes.
On the failure to detect between-group differences in pain, Professor Guedj offered several explanations.
"One hypothesis is that rTMS has an influence on the psychological dimensions involved in quality of life, without effect on neural processing of pain. In our study, improvement of quality of life would be related only to a better perception of health, but not to a pain decrease. We may also hypothesize that our stimulation protocol was too short to detect a global pain improvement.
"rTMS-induced analgesia, rather than acting directly on pain, may be mediated by the translation of changes in emotional processing associated with global pain, thus requiring a delay in action," he concluded.
The study was supported by Marseille Public Hospitals (APHM) and the French National Institute of Health and Medical Research (INSERM).
Neurology. 2014;82:1231-1238. Published online March 26, 2014. Abstract
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Cite this: TMS Benefits Quality of Life in Fibromyalgia - Medscape - Mar 28, 2014.