The Clinical Effect of Low-Intensity Electromagnetic Field Neurostimulation in Fibromyalgia Syndrome Patients

The Clinical Effect of Low-Intensity Electromagnetic Field Neurostimulation in Fibromyalgia Syndrome Patients

The Clinical Effect of Low-Intensity Electromagnetic Field Neurostimulation in Fibromyalgia Syndrome Patients

The purpose of this study is to determine whether persons treated with a low-intensity, noninvasive form of cortical electrical stimulation experience a reduction in symptoms of fibromyalgia different than persons receiving a sham treatment. Outcome measures include reduction in patient pain levels and improvement in sleep measures.

There is increasing acceptance that pain in fibromyalgia is a result of dysfunctional sensory processing in the spinal cord and brain. Electrical cortical stimulation is a device-based form of therapy that is increasingly being considered as an adjuvant to current medical modalities for the treatment of chronic pain conditions such as fibromyalgia. The investigators propose that stimulation of cortical areas believed to be involved in dysfunctional sensory processing may have a beneficial influence on fibromyalgia symptoms. The aim of this randomized double blind, placebo controlled study is to evaluate the efficacy, safety, and tolerability of noninvasive cortical stimulation in the management of fibromyalgia symptoms. More specifically, an active treatment group of subjects will receive the study's cortical stimulation protocol twice a week for 11 weeks and will be evaluated within 14 days following end of treatment, for a total timeframe of 13 weeks. In comparison, a similar group of subjects will receive the same treatment protocol without the actual stimulation signal being applied. The signal utilized is a modulated form that permits very low-intensity signals to pass through outer tissues with less attenuation due to tissue impedance. The signals are of a sufficiently low strength that they are below the level of perception. Hence subjects cannot feel the signal, and are therefore blinded to treatment arm. Investigators and clinical staff are also blinded. Outcome measures include post-treatment to baseline changes in tender points, sleep characteristics as measured by visual analog scales, and outcomes instruments including the Fibromyalgia Impact Questionnaire.

Subjects in this group will receive the noninvasive cortical stimulation signal from the treatment device

Subjects in this group will be provided the same experience as those in the active treatment arm, but will not receive the noninvasive cortical stimulation signal from the treatment device

Subjects will receive 22 sessions of the intervention protocol, twice per week for a total of 11 weeks. The signal stimulation used in this study utilizes amplitude modulation to shape a high frequency carrier signal, nominally greater than 10 kilohertz, into the form of one or more low frequency components, nominally less than 40 hertz. Exact protocol is set in software and is the same for all participants in the active treatment arm.

Subjects in the placebo group will receive the exact same experience as those in the active treatment group. However, the device will not output any electrical stimulation signal.

Tender point pain threshold is derived by summing the dolorimetry-based pain pressure thresholds measured on a subject for each of the 18 tender points sites specified by the American College of Rheumatology for fibromyalgia classification. The range of dolorimeter values for each tender point site is 0-4 (units are kilograms per square centimeter, i.e. kg/cm^2). Higher numbers represent greater pressure required to elicit pain, and are thus indicators of "less pain" sensitivity at the tender point. Since 18 tender points are measured on a patient and their individual dolorimeter values summed, the range of tender point pain threshold values is 0-72. A higher score represents less overall pain sensitivity. The change in tender point pain threshold is determined by subtracting values at baseline from values at end of treatment. Thus a positive difference represents pain improvement (i.e.. a better outcome). A negative difference represents pain worsening (i.e. a worse outcome).

Total timeframe 13 weeks: baseline followed by 11 weeks of treatment with outcome assessed within 14 days following end of treatment

The number of positive tender points ranges from 0-18, and are defined per criteria set forth by the American College of Rheumatology and based on dolorimetry measurements made on 18 prescribed tender point locations. A tender point is considered "positive" if less than 4 kilograms per centimeter squared pressure is required to elicit a painful response. The change in number of positive tender points is determined by subtracting the number of positive tender points at baseline from the number of positive tender points at end of treatment. Thus, a negative number represents pain improvement (i.e. better outcome), whereas a positive number represents a worsening of pain (i.e. worse outcome).

Total timeframe 13 weeks: baseline followed by 11 weeks of treatment with outcome assessed within 14 days following end of treatment

The Fibromyalgia Impact Questionnaire yields a score ranging from 0 to 100, with higher scores representing a greater impact or level of symptoms. The change in Fibromyalgia Impact Questionnaire is determined by subtracting scores at baseline from scores at end of treatment. Thus negative numbers represent symptom improvement (i.e. a better outcome) and positive numbers represent symptom worsening (i.e. a worse outcome).

Total timeframe 13 weeks: baseline followed by 11 weeks of treatment with outcome assessed within 14 days following end of treatment

The Fibromyalgia Impact Questionnaire includes a pain visual analog scale (VAS) with ranges of 0-10 centimeters. Higher values represent greater pain. The change in Fibromyalgia Impact Questionnaire pain visual analog scale is determined by subtracting baseline VAS values from end of treatment VAS values. Thus, a negative value represents pain improvement (i.e. a better outcome), while a positive value represents pain worsening (i.e. a worse outcome).

Total timeframe 13 weeks: baseline followed by 11 weeks of treatment with outcome assessed within 14 days following end of treatment

The Fibromyalgia Impact Questionnaire includes a sleep visual analog scale (VAS) with ranges of 0-10 centimeters. Higher values represent greater difficulty with sleep. The change in Fibromyalgia Impact Questionnaire sleep visual analog scale is determined by subtracting baseline VAS values from end of treatment VAS values. Thus, a negative value represents sleep improvement (i.e. a better outcome), while a positive value represents sleep worsening (i.e. a worse outcome).

Total timeframe 13 weeks: baseline followed by 11 weeks of treatment with outcome assessed within 14 days following end of treatment

Inclusion Criteria: Age 18 through 65 years An ability to read and comprehend English Completion of a minimum of grade 8 education Diagnosis of fibromyalgia in 1999 or earlier, by a rheumatologist or appropriate specialist, and currently meeting the American College of Rheumatology 1990 criteria Symptoms for at least 48 months with no recent remission of symptoms to any degree Exclusion Criteria: Developmental disabilities, or significant psychological disorder (except depression and anxiety disorders) for which treatment has become necessary A history of chronic infection or chronic condition such as lupus, rheumatoid arthritis, Parkinson's Disease, multiple sclerosis, hepatitis, history of meningo-encephalitis, polio, seizures, or metastatic cancer Current pregnancy, or plans to become pregnant during the study period. Any other condition deemed to pose a risk to the patient at the discretion of the investigators Exposure to other neurostimulation systems, or electroconvulsive therapy Any implantable electronic device Any present or previous litigation regarding their physical condition