Repetitive transcranial magnetic stimulation improves quality of life in fibromyalgia

By Will Boggs MD

NEW YORK (Reuters Health) - Repetitive transcranial magnetic stimulation (rTMS) improved quality of life in patients with fibromyalgia, in a randomized, sham-controlled trial.

"Previous neuroimaging studies in patients with fibromyalgia have suggested an alteration of brain processes involved in the regulation of pain and emotion," said Dr. Eric Guedj from Hopital de la Timone and Aix-Marseille Universite, both in Marseille, France in an email.

He told Reuters Health, "The objective was here to demonstrate that it is possible to modulate brain areas, using rTMS, in order to correct functional brain abnormalities and improve patients' symptoms."

Two studies have reported beneficial effects of rTMS on pain and quality of life (QOL) in fibromyalgia patients. High-frequency stimulation would be expected to improve areas affected by hypofunction and thus to affect QOL, rather than to alter pain nociception, Dr. Guedj and colleagues say in their paper.

To study the impact of high-frequency rTMS over the left primary motor cortex on QOL in patients with fibromyalgia, they randomized their subjects to receive actual rTMS of 10 sessions over two weeks followed by four sessions at weeks 4, 6, 8, and 10. Patients randomized to sham rTMS were connected to a sham identical coil of identical appearance.

At the end of week 11, the 16 patients in the active rTMS group had significantly greater improvement in QOL (Fibromyalgia Impact Questionnaire score) than did the 13 patients in the sham rTMS control group (a mean improvement of 9.6 points vs a mean worsening of 2.0 points, p=0.032).

Patients in the active rTMS group also had significantly better improvements in the mental component score of the SF-36, the authors reported online March 26th in Neurology.

There were no other differences between the groups, including pain, mood, and anxiety.

Right medial temporal metabolism, as measured by PET, correlated significantly with QOL scores, especially for nonphysical dimensions.

"The rTMS effects may thus reflect an improvement involving the emotional dimension associated with pain, rather than a direct effect on the sensory component of pain," the investigators explain.

Dr. Guedj concluded that this argues "for a neural substrate to this disorder, and for the possible modulation of brain areas to improve the symptoms."

Dr. Baron Short is the Brain Stimulation Service Medical Director at Medical University of South Carolina in Charleston. He told Reuters Health by email, "rTMS may be a novel treatment for fibromyalgia. There are multiple superficial sites of stimulation (motor cortex, prefrontal cortex (Short), or sensory cortex) and deeper sites (insula, anterior cingulate) that need to be investigated. Furthermore stimulation parameters matter as different regions may reduce pain if they receive excitatory vs. inhibitory stimulation."

"rTMS is a focal brain stimulation technique already FDA approved for the treatment of unipolar depression in 2008," Dr. Short said. "Patients commonly receive 20-30 sessions for an antidepressant effect. There are ongoing rTMS studies in bipolar depression, OCD, Parkinson's, stroke rehabilitation, and smoking cessation, to name a few. We know that folks with fibromyalgia tend to have many adverse systemic drug reactions to pharmacotherapy, but TMS may be more tolerable, while reducing side effects due to focal neurocircuitry modulation."

"I think further work is needed with left prefrontal rTMS stimulation, as this is another site already being studied for changing pain perception in healthy subjects and clinical populations," Dr. Short added. "It may be that optimal TMS treatment may include both motor and prefrontal cortical modulation."

Dr. Alexander Tzabazis from Stanford University School of Medicine, Stanford, California has also studied the use of TMS in fibromyalgia patients. In an email, he told Reuters Health, "Results described in this article, as well as our own work, have provided some interesting data that rTMS can (relieve)fibromyalgia symptoms, improve quality of life, and also reduce fibromyalgia pain. It yet needs to be determined which fibromyalgia patient population will actually benefit from multiple rTMS sessions, which stimulation settings should be used, e.g., stimulation of the primary motor cortex versus prefrontal cortex versus deep brain structures, low versus high frequency, single versus multi-coil stimulation."

"Considering the amount of resources rTMS needs, we are not at a point where it makes sense for every fibromyalgia patient to try it out," Dr. Tzabazis said. "It can very well be that in future, neuroimaging will determine whether or not a particular patient is a good candidate for rTMS treatment."

"Keep an open mind and your eyes open," Dr. Tzabazis concluded. "I am confident that rTMS will become a useful addition to the armamentarium of clinicians in many specialties in the near future."

SOURCE: http://bit.ly/P2pAmF

Neurology 2014;82:1231-1238.

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