Stimulating News For Fibromyalgia Patients

The United States Food and Drug Administration (FDA) approved the device known as the vagus nerve stimulator (VNS) in 1997 as a means of lessening the number of seizures in those with epilepsy. In 2005, the FDA granted approval for VNS use in treating depression for patients who are nonresponsive to medications. Now, the device is undergoing phase II trials to see whether VNS is safe and well tolerated by patients with severe fibromyalgia.

Messenger Blamed

The vagus nerve travels from the area of the neck on into the brain. This section of the nerve is responsible for carrying pain-related and other sensory information to the brain. In this case of "blame it on the messenger" the vagus nerve influences a great many brain processes which occur in various locations of the brain. VNS targets this nerve and researchers hope to use the device to change the way pain information is relayed to the brain. If they succeed, this will improve the quality of life of fibromyalgia patients by reducing their chronic pain.

Just as with any other medical device or drug, VNS must first undergo testing to see if it is safe and well-tolerated by its target group, in this case, fibromyalgia patients. VNS is a battery-operated device that a surgeon implants just below the patient's collarbone in an outpatient procedure, in much the same way as a cardiac pace maker is installed. In order to provide direct stimulus to the vagus nerve, one wire from the stimulator is wound around the left vagus nerve. This type of trial is known as an "add on" because subjects participating in the trial can continue to take their usual medications during the course of the trial.

Side Effects

Participants in the trial have been asked to commit to a full year for the VNS study, with the possibility of continuing with follow-up visits for a further one more year. The researchers are looking for 30 subjects for the trial which is non-randomized, open label, uncontrolled, and consists of only one group assignment. Potential side effects of VNS include cough, shortness of breath on exertion, voice changes, and hoarseness. Intolerance to the device is rare.

The major goal of the trial is to study whether or not VNS is safe and well tolerated in patients with severe fibromyalgia and to see if the data generated tallies with the data on patients treated with this device for epilepsy and depression. An additional goal involves finding out whether VNS can have a positive effect on fibromyalgia symptoms like pain, physical function, mood, and quality of life. Assuming that all goes well, this study is meant to be the basis on which a phase III trial can be planned.

In earlier tests of the device, those patients with epilepsy and depression found that VNS treatment had a side effect: pain relief! This led to another study which showed that patients with depression have a higher pain tolerance when treated with VNS. VNS was also shown to provide relief to epilepsy patients who have chronic migraine headaches.


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