Research using ‘network analysis’ techniques, that were first used by physicists, reveals surprising patterns in pain distributions across the human body
Mirrored pain—where someone experiences pain on both sides of the body in symmetrical regions—is far more common than previously believed, according to a new study.
The study, published in the journal PAIN, analysed over 4,800 drawings in which patients depicted their pain from a Danish population-based cohort. Compiling these records, the researchers saw that pain in one region of the body was much more likely to correspond with pain in the exact opposite side of the body, such as the right elbow and left elbow.
Over one-third of participants reported pain in both sides of the body, with more than 90% of these cases occurring in mirrored regions. These findings challenge long-held assumptions about pain patterns that pain would be most closely related to areas next to each other on the same side of the body.
The study also found an unexpected pattern where pain in one area appears to reduce the likelihood of pain in regions that neighbour the mirrored region, such as pain in the right elbow reducing the likelihood of pain the left hand and the left shoulder.
This suggests that the central nervous system activates at least two mechanisms to affect the likelihood of pain in the opposite side of the body to a painful region – one that increases its likelihood and the other that decreases it. It appears that these mechanisms might even be competing with each other.
This study is the first time that researchers have used a sophisticated network analysis technique on pain location data, which was originally developed to study atoms in magnets.
Lead author, Dr David Evans from the University of Birmingham, said the research could have major implications for our understanding of why we feel pain where we do, and how we might be able to reduce pain. He said:
“These findings challenge conventional wisdom and provide a new perspective on how pain spreads across different body regions. The identification of contralateral inhibition – the reduction of pain in regions on the opposite side of the body adjacent to a symmetrical mirrored region – also raises questions about how our central nervous systems regulate pain perception and may lead to novel therapeutic interventions. The research underscores the importance of considering spatial pain patterns during clinical assessments; for example, the strong tendency for pain to appear in mirrored regions may have implications for diagnosing and treating chronic pain conditions.”
Source: University of Birmingham
Reference: ‘Where is the pain? Spatial patterns of pain co-occurrence in a population-based study of 4,833 pain drawings incorporating Network Analysis’ – David William Evans, PhD, Bernard Xian Wei Liew, PhD, Johan Hviid Andersen, PhD, MD, Søren Mose, PhD is published by PAIN®
Image: Canva
