Reduced alpha-band phase coherence and cortical complexity in fibromyalgia: A tms-eeg exploratory study

Area of Science:

• Neuroscience
• Clinical Medicine
• Biophysics

Background:

• Fibromyalgia is associated with reduced primary motor cortex (M1) excitability.
• Repetitive transcranial magnetic stimulation (TMS) can normalize M1 excitability and alleviate fibromyalgia symptoms.
• TMS combined with electroencephalography (TMS-EEG) measures M1 excitability and brain connectivity.

Purpose of the Study:

• To assess cortical excitability, oscillatory activity, and complexity in fibromyalgia patients compared to healthy controls.
• To investigate neurophysiological abnormalities in fibromyalgia using TMS-EEG.
• To explore the relationship between brain connectivity and clinical symptoms in fibromyalgia.

Main Methods:

• Compared TMS-EEG measures, including global- and local-mean field power, peak-to-peak amplitude, event-related spectral perturbation, intertrial coherence (ITC), natural frequency, and perturbational complexity index (PCIst), between 18 fibromyalgia patients and 15 healthy controls.
• Assessed pain intensity, interference, current therapy, mood, and quality of life in fibromyalgia patients.

Main Results:

• Fibromyalgia patients showed reduced alpha-band ITC in middle- and right-parieto-occipital areas compared to controls.
• Reduced middle-parieto-occipital ITC negatively correlated with reported pain relief.
• The PCIst was lower in fibromyalgia patients and correlated with higher pain interference.

Conclusions:

• Individuals with fibromyalgia demonstrate abnormal cortical connectivity compared to asymptomatic controls.
• TMS-EEG may offer valuable insights into brain connectivity for prognostication and therapeutic strategies in fibromyalgia.
• Altered brain connectivity is a key neurophysiological feature of fibromyalgia.