Our new study explores a neurophysiological marker of chronic pain

We are glad to report in the open-access journal Pain Reports a study of brain neurophysiological signals related to chronic pain.

Chronic pain affects up to 20% of the general population with pervasive sensations of pain of various intensity that may affect lower back, head and neck, gastrointestinal areas, muscles or joints, etc.

The research was proposed and driven by Dr. Cecile de Vos, who was a CIHR Postdoctoral Fellow in the lab and is now faculty at Erasmus Medical Centre in Rotterdam. The data was analyzed by Bart Witjes, who did his Masters research project with Dr. de Vos while visiting us in Montreal.

Objective disease markers are a key for diagnosis and personalized interventions. In chronic pain, such markers are not available and therapy relies on individual patients' reports. Yet, several pain studies have reported group-based differences with varied functional modalities.

Cecile and Bart aimed to explore spectral differences in resting-state MEG brain signals between patients with chronic pain and pain-free controls and to characterize the cortical and subcortical regions involved.

They estimated power spectral density of brain signals over 5 minutes of resting-state MEG in twenty-one patients with chronic pain and 25 controls and derived 7 spectral features at the sensor and source levels. Cecile and Bart were particularly interested in the ratio between slow and fast subcomponents of alpha brain rhythms (8-12 Hz).

No significant group differences were found in alpha peak frequency or average power in any frequency band. However, the alpha power ratio (between slow and fast subcomponents of alpha-band brain rhythms) was significantly higher in patients with chronic pain.

The brain regions showing significantly higher alpha ratios included the occipital, parietal, temporal and frontal lobe areas, insular and cingulate cortex, and right thalamus.

To conclude, the alpha power ratio is a simple, promising signal marker of chronic pain, affecting an expansive range of cortical and subcortical regions, including known pain-processing areas.

To learn more, the article is freely accessible from the Pain Reports website:

Witjes B, Baillet S, Roy M, Oostenveld R, J P M Huygen F, C de Vos C. Magnetoencephalography reveals increased slow-to-fast alpha power ratios in patients with chronic pain. Pain Rep. 2021 Jun 3;6(2):e928.

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