Mismatched Systems

Sometimes we read about medical research and wonder, “Now, how the heck did they come up with that idea??”

They’ve done it again, folks. This time, researchers asked fibromyalgia patients to watch their arm in a mirror while moving their second arm, hidden behind the mirror, in the opposite direction. The results of this recent study published in the journal Rheumatology shows that fibromyalgia pain results from a mismatch between the sensory and motor systems. The directions of the researchers caused the brains of the fibromyalgia patients to experience a mismatch between what it sees (sensory input) and what it feels (motor system and movement control).

26 out of the 29 participants in the study said they felt an increase in pain, a change in temperature, or experienced a sensation of heaviness in the arm that was hidden from view. These symptoms suggest that the exercise triggered a recurrence of fibromyalgia symptoms. Researchers believe that the results of their study suggest that the root of the fibromyalgia condition might be attributed to a motor/sensory mix-up.

Goes Undetected

Dr. Candy McCabe, a researcher at the University of Bath and Royal National Hospital for Rheumatic Diseases and an author of the study commented that fibromyalgia is hard to understand because the chronic pain experienced by sufferers goes undetected in clinical examination. In the UK study, researchers were able to demonstrate that confusion between the motor and sensory systems can bring about an exacerbation of the symptoms experienced by fibromyalgia patients.

Pause to Reflect

McCabe comments on just how such research has been found to be helpful in treating fibromyalgia. “We have had some success to date in using a similar technique to help alleviate the symptoms of this kind of chronic pain. This works by helping the brain to see a limb moving freely without pain – although in reality it is a reflection of their pain-free limb.”

Participants in the study moved their arms up and down while in front of a mirror with a right angle view. This meant that one limb was hidden from view by the mirror, though the other arm could be seen both by the naked eye as well as in the mirror’s reflection. The volunteers first moved the same way with both limbs, and then moved in different patterns at once. Researchers were able to see the direct effects of how the varied movements confused the brains of the participants.

Just about all of the participants reported greater sensations in the hidden limb, proving that a conflict between the sensory and motor systems may be at the heart of the fibromyalgia condition. This is an important finding for a condition which some clinicians refuse to believe is real, since it goes undetected by clinical examination. These clinicians believe that fibromyalgia is a manifestation of anxiety or a type of attention-getting behavior. In spite of this, rheumatologists tend to see more fibromyalgia than any other condition.