Electrodiagnostic Abnormalities Associated with Fibromyalgia

Area of Science:

• Neurology
• Rheumatology
• Neurophysiology

Background:

• Fibromyalgia is increasingly recognized as a neurological disorder.
• A hypothesis suggests nerve root irritation from elevated cerebrospinal pressure may cause fibromyalgia.
• Neurogenic abnormalities are predicted to be most severe in sacral nerve roots due to pressure gradients.

Purpose of the Study:

• To review electrodiagnostic test results in patients diagnosed with fibromyalgia.
• To investigate potential neurological dysfunction in fibromyalgia patients.

Main Methods:

• Retrospective review of electrodiagnostic tests in 17 female fibromyalgia patients.
• Tests included lumbar and sacral nerve root myotome assessments.
• Diagnosis based on 1990 American College of Rheumatology criteria.

Main Results:

• Abnormalities were observed in sural nerve responses, S1-Hoffmann reflexes, and fibular motor nerve conduction.
• Needle electromyography (EMG) revealed neurogenic motor unit potentials in multiple lumbar and sacral myotomes.
• Delayed anal reflexes (S3-S4 myotomes) were present in 94% of patients, with sacral abnormalities more pronounced than lumbar.

Conclusions:

• This study presents the first electrodiagnostic data for lumbar and sacral nerve roots in fibromyalgia.
• Neurogenic abnormalities were noted in all patients, predominantly in the sacral region.
• Anal reflex assessment may be a valuable diagnostic tool for fibromyalgia, alongside small fiber neuropathy testing.