Role of Myofascial Trigger Points in Fibromyalgia Syndrome - Part 1
Principal Investigator: Hong-You Ge, M.D., Ph.D.
Aalborg University, Denmark
Award Amount (September 2008): $30,000
Hong-You Ge, M.D., Ph.D., and his colleagues at Aalborg University in Denmark, plan to evaluate 30 fibromyalgia syndrome (FMS) patients and 30 healthy age-matched control subjects for the presence of active and latent MTPs. Initially the MTPs and their referred pain patterns will be identified by careful palpation of the muscles in the neck, shoulders, low back, and extremities. The pressure pain thresholds at all myofascial trigger points (MTPs) will also be measured. An anatomical map of the latent and active MTPs, as well as the areas of referred pain will be generated for each subject. Ge’s team also will confirm the presence of each MTP by measuring its electrical activity with electromyography (EMG).
In a second session one week later, subjects will be evaluated at the 18 diagnostic tender areas for FMS. Ge will look for the presence of latent or active MTPs at or near the 18 tender points. He will also determine if any of the tender points are located in an area of referred pain generated by an MTP. In addition, the MTPs will be confirmed by EMG. Since a tender point exam is done to identify areas of lowered pain threshold and MTPs have been documented to cause a lowering of pressure pain thresholds, it’s plausible that the 18 tender points might possibly be MTPs, but this has never been explored.
To fully assess the extent to which MTPs contribute to the generalized pain of FMS, Ge proposes to look at the impact of treating the MTPs in “Part 2” of his study. Upon successful completion of the evaluation phase, AFSA has already pre-approved the funding of Ge’s treatment phase. Obviously, if effective treatment of the MTPs does lead to significant pain and symptom relief, this would provide important evidence of the role of MTPs in FMS and will prompt increased education on the treatment of MTPs.
Myofascial Trigger Points and Central Sensitization in People with Fibromyalgia Syndrome
Principal Investigator: César Fernández de las Peñas, P.T., Ph.D.
Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain
Award Amount (September 2008): $25,000
César Fernández de las Peñas, P.T., Ph.D., and his colleagues in Spain, propose to evaluate the role of myofascial trigger points (MTPs) in generating fibromyalgia syndrome (FMS) symptoms using a different approach from that of Ge’s team. Fifty FMS patients and 50 healthy age-matched controls will be carefully examined for the presence of active and latent MTPs. The referred pain patterns of each active MTP will also be charted. Muscles in the head, neck, shoulders, back, buttocks, legs, and forearms will be physically assessed for the presence of firm nodules and pain tenderness to identify the MTPs and their associated referral pain patterns. This will provide insight about each person’s peripheral pain generators in their muscles.
All subjects will undergo sensory pain testing to determine thresholds to pressure, cold, and heat pain. Muscles throughout the body will be used in these tests, which are designed to reflect impairments in the central nervous system’s ability to process pain. In addition, participants will fill out validated questionnaires to assess quality of life, physical functioning, and pain severity.
Statistical analyses will be performed to determine how the number of active and latent MTPs influence the sensory processing system, quality of life, functional ability, and overall pain severity.
The 18 diagnostic tender points will also be assessed to determine if any of the tender points are nearby active or latent MTPs, or in an area of referred pain that is produced by an active MTP. The goal of this part of the study is the same as that of Ge’s, because it will take more than one research team or medical journal report to draw attention to the possible overlap between the diagnostic tender points of FMS and the presence of MTPs.
Impact of Fibromyalgia on Brain Aging and Cognitive Function
Principal Investigator: M. Catherine Bushnell, Ph.D.
McGill University, Montreal, Canada
Award Amount (August 2008): $59,800
Several memory and mental processing tests show that fibromyalgia syndrome (FMS) patients have good reason to be complaining about their cognitive function, or what is called “fibro fog.” Putting your thought processes into perspective, one study showed that you are functioning at a level that is 20 years older than your actual age.1 Not surprisingly, last year M. Catherine Bushnell, Ph.D., of McGill University in Montreal, Canada, reported a premature loss of gray matter in several areas of the brain involved in pain and memory processing.2 The study was small and compared ten FMS patients to ten healthy pain-free control subjects (all women and age-matched to reduce variability).
As a person with FMS, you most likely want to know what the loss in gray matter means. Is it linked to your symptoms of pain? Does it correspond to your cognitive dysfunction? Or, perhaps loss of gray matter is tied to many symptoms. The initial study showed that gray matter loss increased with duration of symptoms, so a study involving a larger number of subjects is certainly warranted.
“It is well documented that cognitive functions, such as speed of information processing, working memory, and long-term memory, decline continuously across the adult life span beginning in the second decade of life,” says Bushnell. “So an obvious question arising from our preliminary findings is: ‘What is the relationship between accelerated brain aging in FMS patients and cognitive function?’ To answer this question, our study will examine the relationship between brain anatomy and different measures of cognitive functioning in 30 non-depressed, medication-free FMS patients. We will test the hypothesis that FMS patients have an increased age-related decline in cognitive functioning. We will determine the degree of dysfunction and the amount of gray matter loss relative to 30 age-matched control subjects.”
Other important goals of the study will be to determine if loss of gray matter correlates with:
- pain threshold and other experimental measures of pain
- level of physical functioning, and
- fatigue scores
It’s essential that fatigue or alertness be excluded as the cause of the cognitive difficulties in FMS patients. Given that widespread pain is present in all patients, how is this symptom related to the loss of gray matter and cognitive dysfunction? Could pain be distracting or interfering with a person’s ability to process information? Also, how does the gray matter loss relate to a patient’s functional ability (or disease severity) and duration of symptoms?
Answers to these questions are needed to better characterize the significance of the gray matter loss, as well as the interrelationships between pain, fatigue, physical function, and cognitive abilities. If accelerated gray matter loss is found to correlate with diminished cognitive function, then efforts must be placed on early identification of FMS as well as testing therapies that can reduce or reverse the structural changes in the brain.
1. Park DC, et al. Arthritis Rheum 44(9):2125-33, 2001.
2. Kuchinad A, et al. J Neurosci 27(15):4004-7, 2007.
Low-Dose Naltrexone for the Treatment of Fibromyalgia
Principal Investigators: Jarred Younger, Ph.D., and Sean Mackey, M.D., Ph.D.
Stanford University, Palo Alto, California
Award Amount: $50,000
Relief from chronic pain is difficult to achieve, and this may be partly explained by the fact that there are two targets: the neurons and the nearby glial cells. All drugs to date were designed to work on the neurons, but some of them have the ability to alter the function of the glial cells. Naltrexone is one of them.
Under normal circumstances, the glial cells provide the neurons with nutrients and are silent in the role of pain transmission. However, many glia-activating substances are elevated in the spinal fluid of people with fibromyalgia syndrome (FMS), such as substance P, nerve growth factor, and even opioids produced by the body. Activated glial cells produce a surge of pro-inflammatory cytokines, including interferon, tumor necrosis factor, and various interleukins, which then sensitize the nerve fibers. The goal of the study is to reduce the sensitization of the pain-transmitting nerve fibers that are believe to be involved in FMS.
AFSA has funded Younger and Mackey to test a novel treatment option of low-dose naltrexone to relieve the symptoms of FMS. In normal doses (around 50 mg), the drug blocks pain-relieving chemicals such as endorphins (the body’s own opioids). This would certainly not be desirable for people with FMS, but the drug also blocks the activation of the glial cells so they do not produce pain-promoting substances. The key is to use a smaller dose of naltrexone (3-4.5 mg), which may still “chill out” the glial cells while not appreciably interfering with the body’s own opioid pain relievers.
The ability of naltrexone to shut down the pain-promoting activities of the glial cells was recently discovered and appears to be safe. It has been tested in small trials for the treatment of Crohn’s disease and multiple sclerosis pain. Now it will be determined if the drug can benefit individuals with FMS.
Forty people with FMS will participate in the trial. For part of the study, these individuals will receive low-dose naltrexone every night before bedtime. For another part of the study, they will receive an inactive placebo substance. Neither the participants nor the researchers will know what the participants are receiving until the study is completed. In a research plan called a crossover design, participants will start on either the drug or placebo, and will then switch to the other substance. A two-week period will separate the conditions so the drug can leave the body.
Participants will fill out a short questionnaire every night to chart their pain levels, sleep quality, physical activity, mood, fatigue and other aspects related to FMS. These symptom values will be collected on hand-held computers (e.g., palm pilots) and will allow the researchers to conduct very powerful tests of the drug’s effectiveness. For example, an analysis of the data may show that daily fatigue and pain are both reduced when a person is taking the drug. The method will also allow the researchers to identify which symptoms improve first. In addition, participants will visit the Stanford Pain Clinic Lab every two weeks to undergo more thorough and objective tests of pain sensitivity.
Finally, it is well-known that not all people will react well to a certain drug. Participants will undergo a variety of tests at the beginning of the study to determine the characteristics of the patients who reap the most relief from the medication. This will help physicians determine which individuals should receive the medication.