Brain Imaging Fibro Fatigue
After pain, fatigue is the next most difficult-to-handle symptom of fibromyalgia . Just trying to get tasks done is an effort, which patients describe as “having to push” themselves. The fatigue of fibromyalgia is not ordinary tiredness and a recent brain imaging study may offer clues as to why patients struggle so much with this symptom.1
Loss of gray matter in the brain of fibromyalgia patients has been documented by a number of magnetic resonance imaging (MRI) studies, but the location of the loss is inconsistent. The most recent study, headed up by Basant K. Puri, Ph.D., in the United Kingdom, used an MRI machine that was twice as powerful at detecting changes in the brain than previous reports. In addition, Puri reduced variability among the fibro group by only evaluating women with severe fatigue, but no other medical conditions that could cause tiredness.
The study compared the MRIs from the five fatigued women with fibromyalgia to age-matched healthy women. Puri found a significant gray matter reduction in an area of the brain that is essential for regulating movement: the supplementary motor area (SMA). Although the “supplementary” title for this region implies it’s a secondary control area, this is a deceiving label.
The SMA has connections to your motor neurons, which control your muscle movements. In fact, the SMA becomes activated before you actually move your muscles. Even the mere thought of performing an activity gets the SMA active. For example, if you visualized raising your right arm, your SMA would become activated because this area is involved in the cognitive or thought processes pertaining to movement.
If loss of gray matter in the SMA leads to reduced function of this area, this could explain why the fatigue in fibromyalgia is not simply relieved by rest and why patients feel they must push themselves. If the brain area controlling movement decisions is even the slightest bit impaired, it could explain why the fatigue is not just a case of being tired.
The SMA is involved in other processes besides the cognitive control of movement. It has two other important functions: (1) to enable you to inhibit one response and go with another, and (2) to reduce the impact of distractions so that you can think more clearly.
If you read our Latest News report describing how fibromyalgia patients tend to fail the Stroop Test, you may relate to this first function.2 The Stroop is a cognitive test in which people are presented a card with a color word (such as “blue”) printed on it in ink that is red. In order to get the answer correct, a person must inhibit the visual cue of “red” and read the card as “blue.”
If you find that the least bit of distraction jumbles up your ability to concentrate, a common problem in fibromyalgia patients, this could possibly be due to malfunctions in the SMA. The SMA is supposed to filter out distractions and reduce the symptom commonly referred to as “fibro fog.”
The study by Puri is only based on five fibromyalgia patients and five controls. It is a good start on the path of trying to explain the unusual fatigue and fibro fog exhibited by most people with fibromyalgia. Puri admits that “larger studies are now indicated in fibromyalgia associated with marked fatigue compared with fibromyalgia without marked fatigue and healthy controls.”
1. Puri BK, et al. J Int Med Res 38:1468-1472, 2010.
2. For a more information on the Stroop Test and its implications for fibromylagia patients, and to access a link where you can take the test yourself, please see our Latest News Report from July 31, 2008.