Numerous studies have found that altered activity in several parts of the brain correlates with pain and fatigue in Fibromyalgia and Chronic Fatigue Syndrome. rTMS, which uses a magnetic coil to alter brain activity levels, has been found to improve the symptoms of a wide variety of neurological and psychiatric disorders in including migraine, stroke, tinnitus, Parkinson’s and depression. It can reduce or increase the excitability of the corticospinal tract depending on the configuration of the coils.
Repetitive transcranial magnetic stimulation (rTMS) technology has been stymied to some extent in FM by its inability to reach the deeper brain regions affected in the disorder. Two methods used to do this thus far have been unsuccessful; cranking up the power of the magnet can burn the scalp (and cause seizures!), while enlarging the diameter of the magnetic coils to allow the magnetic field to penetrate deeper into the brain results in less precision and can cause side effects.
The Fibromyalgia/pain sensitization market is a lucrative one, however, and advances in rTMS technology are occurring rapidly with numerous clinical trials underway.
This study used a new approach to target the deeply buried anterior cingulate region, a part of the brain that has been implicated multiple times in both Fibromyalgia and Chronic Fatigue Syndrome.
The anterior cingulate cortex, with its effect not only on autonomic nervous system functioning but on cognition (decision-making, reward anticipation) and pain, almost seems made to order for Fibromyalgia. This study targeted the dorsal region of the anterior cingulate cortex which is connected with the prefrontal cortex – a major player in chronic pain.
First, they tested the efficacy of three coil configurations, one of which reduced pain, one which increased pain, and one which had variable effects, and then gave healthy controls and people with Fibromyalgia 20 sessions of the two positive configurations.
Former studies targeting an upper brain region (prefrontal cortex) achieved a 29% reduction in pain in FM- a good finding in this hard to treat disorder – but one configuration in this present study almost doubled that result, achieving a 56% reduction in pain four weeks after the last treatment.
This suggested either the longer treatment duration (20 sessions vs 10) or the different target (the ACC vs the prefrontal cortex) were responsible for the decreased pain. It will be interesting to see, as rTMS machine penetrate the deeper areas of the brain, how much more effective they become.
The relatively long-lived nature of the effect suggested to the researchers that the rTMS was having neuroplastic results; i.e. it was altered neural pathways in the brain. (Increased pain sensitivity is due to a neuroplastic process which results in the pain neurons firing in response to very small stimuli.) They recommended that future studies determine if the rTMS was altering brain structure and connectivity.
The fact that different coil configurations were needed to reduce pain in healthy controls (given a heat stimulus) and in Fibromyalgia patients suggested, as Apkarian’s brain scans have indicated, that pain is produced in different regions in the brains of healthy people and in people with chronic pain.
Interestingly, given recent findings suggesting altered disease processes occur over time in ME/CFS, the authors suggested that different coil configurations may be necessary for patients of different ages.
Many questions remain to be answered about rTMS, the most prominent of which may be its affordability. A 2009 study which estimated average costs at $300/session suggests the 20 days of rTMS in this study would probably cost upwards of $6,000, putting it out of the reach of many people if it is not covered by insurance.
Several studies, however, have found it to be helpful and its non-invasive, usually side-effect free approach is appealing. As the technology improves and researchers can alter the activity levels of deeper and deeper parts of the brain, it’s effectiveness may increase as well. This is a technology to keep an eye on.
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