Fibromyalgia: Increased reactivity of the muscle membrane and a role of central regulation

Abstract

Muscle fiber conduction in fibromyalgia is precipitated by changed membrane physiology.Muscle membrane conduction speed in fibromyalgia rises excessively when adopting a limb position.The muscle membrane in fibromyalgia is probably hyperactive due to deregulation from higher systems.

Key Milestones Contributing to the Understanding of the Mechanisms Underlying Fibromyalgia

“…Other studies on muscle metabolism, when patients with equal general fitness and muscle disuse are used as controls, did not show changes specific to fibromyalgia [ 20 , 21 ]. However, abnormalities in muscle physiology are observed in fibromyalgia [ 22 ], with augmented muscle membrane propagation reactions independent of force load or amount of muscle activity, suggesting central deregulation [ 23 ].…”

Modified 2016 American College of Rheumatology Fibromyalgia Criteria, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks–American Pain Society Pain Taxonomy, and the Prevalence of Fibromyalgia

“…It may be useful to consider other pain cutoff points. The criteria used by Yunus et al (22, 23) required only pain or aching at ≥3 anatomic sites and a miscellany of non‐pain symptoms. The ACR 1990 criteria (1) required 4 (rarely 3) pain sites compared to the 6 in the AAPT criteria, and conditionally more in the FM 2016 criteria.…”

Chronic fatigue syndrome: Abnormally fast muscle fiber conduction in the membranes of motor units at low static force load

“…This is not only in the painful/clinically affected muscles (Gerdle et al, 2008), but also in non-painful/unaffected ones (Casale et al, 2009;Klaver-Krol et al, 2012). Our previous study suggests that this increased CV in FM is due to a disturbed central motor regulation, with increased facilitation or lacking inhibition on the muscle membrane (Klaver-Krol et al, 2019). The purpose of the present study has been to investigate if patients with CFS also show abnormalities in their CV and, if so, to identify the differences between the disturbances in CFS and FM patients.…”

“…no rheumatologic disease) (Yunus et al, 1981), fulfilling the 1990 ACR criteria for FM that includes having at least 11 of the 18 standardized tender points (TPs) in the muscles (Wolfe et al, 1990), not meeting the 1994 criteria of Fukuda (Fukuda et al, 1994), diagnosed by a rheumatologist, female, age above 18 years, and the symptoms' duration of at least two years. Exclusion criterion for the patients was a severe disablement that would disturb the test performance, such as the uses of a wheelchair and/or orthoses (Klaver-Krol et al, 2019). Exclusion criteria for all participants were: pain in the dominant arm (because the strength is then lower); obesity (body mass index > 28); diabetes mellitus, cardiovascular, lung or renal diseases, hypothyroidism, hyperthyroidism, myopathy, neuropathy and malignancy (these disorders can influence CV).…”

“…We analyzed the changes in sEMG that occur on applying a force load. Motor unit action potentials (MUPs) together with their conduction velocities (CV-MUPs) were extracted from the sEMG signal (Klaver-Krol et al, 2019). From these CV-MUPs, we obtained the average CV, and also information on the statistical distribution of the CV-MUPs.…”