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

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

Clin Neurophysiol. 2018 Oct 31;130(1):12-19

Authors: Klaver-Krol EG, Rasker JJ, Klaver MM, Ten Klooster PM, Zwarts MJ

Abstract
OBJECTIVE: Fibromyalgia (FM) is characterized by widespread muscle pain and central neural deregulation. Previous studies showed increased muscle fiber conduction velocity (CV) in non-painful muscles of FM patients. This study investigates the relationship between central activation and the CV in FM.
METHODS: Twenty-two females with primary FM and 21 controls underwent surface electromyography of the non-painful biceps brachii. Mean CVs were calculated from the motor unit potential velocities (CV-MUPs), and the CV-MUPs' statistical distributions were presented as histograms. The amount of muscle activity (average rectified voltage, ARV) was measured.
RESULTS: The CV was higher in the FM-group than in the controls (P = 0.021), with CV-MUPs generally shifted to higher values, indicative of increased muscle membrane propagation speeds. The largest increase in the CV of the FM-group occurred when adopting and maintaining a limb position at only 5% of maximum strength (P < 0.001); the CV did not, as normal, increase with greater force. However, the ARV in both groups similarly increased with force.
CONCLUSIONS: In fibromyalgia patients, the muscle membrane propagation speed increases independently of the force load or amount of muscle activity produced. When adopting a limb position, the patients show an augmented muscle membrane reaction, suggesting deregulation from higher neural centers.
SIGNIFICANCE: These findings contribute to understanding fibromyalgia.

PMID: 30471468 [PubMed - as supplied by publisher]

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