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brain stimulationThe following is a summary of “Non-invasive brain stimulation beyond the motor cortex: A systematic review and meta-analysis exploring effects on quantitative sensory testing in clinical pain,” published in the October 2024 issue of Pain by Flood et al.  

Non-invasive brain stimulation (NIBS) has been increasingly investigated as a treatment for pain, with the traditional protocols focusing on the primary motor cortex (M1), though its effectiveness was later attributed to effects on interconnected cortical and subcortical areas rather than M1 itself.  

Researchers conducted a retrospective study evaluating the effect of NIBS over non-primary M1 sites on quantitative sensory testing measures in clinical pain populations.  

They searched electronic databases from inception to January 2024 and included articles (13 trials, n = 565 participants) which were evaluated using the Physiotherapy Evidence Database (PEDro) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system and a random effects model was applied to meta-analyze outcomes where feasible.  

The results showed that a limited number of studies indicated NIBS applied to the dorsolateral prefrontal cortex might enhance pain modulation in individuals with fibromyalgia, while stimulation of the posterior superior insula and prefrontal cortex could reduce pain sensitivity in chronic neuropathic and osteoarthritic pain, respectively.   

They concluded the current literature did not provide clear evidence that NIBS over non-primary M1 sites influences pain processing. 

Source: academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnae103/7822451