The Effect of Sympathetic Dysfunction on Muscle Spindle in Fibromyalgia

The Effect of Sympathetic Dysfunction on Muscle Spindle Activity in Patients With Fibromyalgia Syndrome

This study aims to reveal whether there is an impairment in the sympathetic regulation of muscle spindle sensitivity in patients with fibromyalgia syndrome (FMS).

The common muscle pain and fatigue symptoms of FMS can be explained by impaired sympathetic regulation of muscle spindle sensitivity. The aim of this study is to reveal whether there is an impairment in the sympathetic regulation of muscle spindle sensitivity in FMS patients. Material method: In the first stage, resting sympathetic tone measurement and resting H-reflex and T-reflex recordings will be taken in all cases. Sympathetic tone measurement will be performed and H-reflex and T-reflex recordings will be taken during and after sympathetic stimulation maneuvers (mental arithmetic calculation and cold application) in FMS patients and healthy control subjects. In the second phase, the first dose of pregabalin will be given to patients diagnosed with FMS and prescribed pregabalin. Pregabalin is known to reduce sympathetic activity in FMS. After oral administration of pregabalin, its peak plasma concentration is reached in 0.9-1.3 hours. Therefore, 1.5 hours later, sympathetic tone measurement will be made at rest and during the sympathetic stimulation maneuver, and H-reflex and T-reflex recordings will be taken. Patients in the healthy control group will not be given pregabalin.

In order to ensure that the researcher who took the recordings is blind, sympathetic tone measurement will be made at rest and during the sympathetic stimulation maneuver in healthy subjects 1.5 hours later, and H-reflex and T-reflex recordings will be taken.

In the first phase of the experiment, the effect of sympathetic tone change on T- and H-reflexes will be evaluated. In the second phase of the experiment, 150 mg (single dose) of pregabalin will be given to these patients to reduce sympathetic activity and evaluate its effect on T- and H-reflexes.

Mental arithmetic calculation and cold pressure increase sympathetic tone. For the mental arithmetic task, the subject is asked to mentally subtract a two-digit number from a four-digit number and respond within 5 seconds. This arithmetic calculation is repeated for different numbers. This test is continued for three minutes. For the cold pressure test, subjects are asked to immerse their right hand in 2-4 degrees cold water up to the elbow and hold it in the water for three minutes. The mental arithmetic task and cold stress test will be applied simultaneously.

In the second phase of the experiment, 150 mg (single dose) of pregabalin will be given to FMS patients to reduce sympathetic activity and evaluate its effect on T- and H-reflexes.

In order to elicit the right soleus T-reflex, a constant-intensity strike will be made on the Achilles tendon with a reflex hammer at intervals of 10-15 seconds. An accelerometer will be placed over the Achilles tendon to measure T-reflex latency and confirm that strike intensities are constant. Recordings will be taken from the right soleus muscle. T-reflex peak-to-peak amplitudes will be measured in electromyographic recordings.

The right tibial nerve will be stimulated with a monopolar technique from the popliteal region to elicit the soleus H-reflex response. The stimulation electrode (cathode) will be placed on the tibial nerve in the popliteal fossa and the anode will be placed on the prepatellar region. For stimulation, a 1ms monophasic square wave pulse current will be given. Mmax will be determined firstly.The current intensity providing a 10% Mmax response will be used to test the H-reflex response. H-reflex peak-to-peak amplitude will be measured in electromyographic recordings.

Sympathetic tone will be evaluated by measuring heart rate variability in the ECG recording taken from the DII lead.

Inclusion Criteria: For the fibromyalgia group Patients diagnosed with FMS based on the American college of rheumatology - 2016 criteria Between the ages of 20-50 Being a woman Patients prescribed pregabalin for the treatment For the Healthy Control group Between the ages of 20-50 Being a woman Being healthy Exclusion Criteria: Those with medical problems in the right upper and lower extremities (skin, neuromuscular, joint, vascular pathologies) Cases that cannot perform arithmetic operations Cold allergy Heart disease (arrhythmia, ischemic heart disease, heart failure) Hypertension Epilepsy

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