Analyzing chronic pain

Nov 18, 2005

Kettering research continues to explore the use of technologies to unravel the causes of Fibromyalgia Syndrome. The newest technology involves decoding the function of the brain by analyzing electroencephalographic (EEG) readings.

Spinning off from his research involving treatments for Fibromyalgia Syndrome (FMS), a full body chronic pain condition that makes a person feel like they have the flu every day of their life, Dr. Jeff Hargrove, associate professor of Mechanical Engineering at Kettering University and adjunct assistant professor of Internal Medicine at Michigan State University, is working with undergraduate student Janet Mueller, of Warwick, N.Y., on a clinical research study using EEG readings to analyze the brain response of FMS patients when subjected to stimuli known to cause central nervous system response in these patients.

Hargrove and Mueller are conducting the clinical trial at Genesys Regional Medical Center as an offshoot of Hargrove's clinical trial to study the effects of low-intensity electrical neurostimulation on FMS patients in collaboration with McLaren Regional Medical Center. That research began in 2002.

Using EEG reading is somewhat new to chronic pain study, according to Mueller. "EEG readings have been widely used to quantify brain activity before," she said. Hargrove added, "What this research will do is to see if we can measure differences in how the brains of healthy individuals respond to painful stimuli as compared to FMS patients." Doing so may shed clues as to the differences in how the brain processes pain, as well as possibly provide ways of diagnosing pain in FMS patients, he said.

Collaborating researchers in the EEG study include: Dr. John Herzog of Genesys RMC and Dr. Don Deering of NeuroHealth Management, LLC.

"Fibromyalgia is a disease believed to be caused by neurochemical imbalances arising from abnormal brain function," said Hargrove. "The illness is characterized by debilitating full body diffuse pain, cognitive dysfunction and sleep disorders." To treat this, Hargrove is investigating treatment techniques that involve sending a small electrical impulse into the brain to stimulate the brain to function normally. The impulse is so slight it cannot be felt during treatment," he said.

Hargrove's work also includes studying the effect of respiratory muscle fatigue and chronic hypocapnia (a reduction in blood CO2) in perpetuating a number of symptoms associated with the illness beyond pain.

As part of the EEG clinical trial at Genesys, FMS patients will be treated using the neurostimulation process to establish whether or not the EEG responses change in patients after treatment. "We'll be looking at electroencephalographic (EEG) patterns of FMS patients before and after neurostimulation treatment, under the conditions of resting EEG, EEG when the individual is subjected to tender point pressure using standard algometry measures, and when the individual is being asked to recall a particularly stressful time in life," said Hargrove. Analysis of the EEG will be carried out using Fourier analysis and wavelet analysis.

Patients included will be those referred into the study by their physician and who have stable primary FMS confirmed by American College of Rheumatology (ACR) 1990 criteria. Ten patients will receive active neurostimulation treatment, and ten more patients will receive sham neurostimulation (i.e. a placebo). Ten healthy normal controls will have their EEG measured, but will not be treated.

For all patients, tender point pressure will be applied with an algometer, and the level required to elicit a painful response prior to treatment will be recorded. The stressful event the patient is asked to recall will be recorded prior to treatment.

In the after-treatment analysis, the researcher will ask the patient to recall the same event, and the same level of algometer pressure will be applied to the same tender points as was used before treatment. In both cases, newEEG readings will be measured.

The before-treatment and after-treatment EEG readings will form the basis of comparison. The true treatment group will be compared to the placebo group, and all groups will be compared to the healthy normals as control measures.

Basic clinical measures of FMS status will be recorded before and after treatment (e.g. Fibromyalgia Impact Questionnaire (FIQ) scores, pain patterns charts, tender point pain, appropriate visual analog scales) to determine change in overall condition.

Hargrove and Mueller hope the end result is an accurate method of identifying EEG patterns that may be specific to FMS patients, and to further understand the extent of the treatment value of the neurostimulation technique.

Written by Dawn Hibbard