Research uncovers how brain activity patterns can predict pain sensitivity

In an international effort, researchers at Western University, the University of Maryland School of Dentistry (UMSOD) and Neuroscience Research Australia (NeuRA) uncovered how specific patterns in brain activity can predict an individual's sensitivity to pain, expanding opportunities for improved pain management strategies. 

The new study was published Jan. 27 in JAMA Neurology. It found the combination of two biomarkers in the brain – corticomotor excitability (CME), excitability in the region of the brain that controls movement, and peak alpha frequency (PAF), a neural marker associated with cognitive performance – can accurately and reliably distinguish high- and low-pain sensitive individuals during prolonged pain. 

"The burden of chronic pain is massive. Having objective biomarkers would greatly assist with decision making in the diagnosis, prevention and treatment of chronic pain," said senior author and Schulich School of Medicine & Dentistry professor David Seminowicz, who started this study while he was a professor at UMSOD. 

For people who suffer from prolonged or chronic pain, this means they could be more effectively treated according to their level of pain sensitivity. 

According to recent data from the Global Burden of Disease study, approximately 1.7 billion people around the world live with musculoskeletal conditions, typically characterized by persistent pain, including pain in muscles, bones, joints, ligaments and tendons. Living with prolonged pain can be debilitating and affect a person's ability to work or socialize. Currently, there is a lack of effective treatments for chronic pain and a gap in understanding the transition from acute to chronic pain. 

For the first time we have something that looks like it could predict pain outcome for people."

Siobhan Schabrun, co-author and professor at Western's School of Physical Therapy

The researchers looked specifically at jaw pain typically attributed to problems with the joint or muscles in the jaw, also known as temporomandibular disorders. 

The study involved 150 participants in Australia, aged 18 to 44. PAF, the brain biomarker associated with cognitive performance, was measured using electroencephalography (EEG) recording, which records electrical activity in the brain using electrodes. CME, the biomarker related to excitability, was measured through transcranial magnetic stimulation, where nerve cells in the brain are stimulated using magnetic fields. 

This research was a collaborative effort between Nahian Chowdhury, research fellow at NeuRA, who led the data collection; a statistical team led by University of Maryland School of Medicine postdoctoral fellow Chuan Bi and professor Shuo Chen; and principal investigator of the UMSOD site, assistant professor Joyce Teixeira Da Silva. 

Slow PAF and low CME indicates higher pain sensitivity 

"Our results suggest individuals who have slow PAF prior to a prolonged pain episode and reduced CME shortly after the onset of a prolonged pain episode are more likely to experience higher pain days or weeks later." explained Seminowicz. 

Additional findings from complementary studies indicate individuals with low levels of CME during the acute stages of low back pain were more likely to develop chronic pain after six months. 

The new research also shows potential to measure PAF and CME in pre-operative and post-injury settings to identify whether a patient has high- or low-pain sensitivity. 

Based on previous literature that found higher acute pain can predict the development of chronic pain, the researchers suggest these biomarkers, PAF and CME, could potentially be used to gauge a person's likelihood of developing chronic pain after an experience with acute pain. 

'A major leap forward' 

"This study represents a major leap forward in the field of pain science. A biomarker that can predict pain sensitivity with 88 per cent accuracy has the potential to transform the treatment and prevention of pain in future," said Schabrun, who is also William and Lynne Gray Endowed Research Chair in Mobility and Activity at St. Joseph's Health Care London. 

Backed by the high rates of accuracy, reproducibility and reliability of their study, the researchers are now working to validate the biomarker in clinical populations to explore clinical translation, including predicting the transition from acute to chronic clinical pain. 

"This would allow us to target treatments toward people with acute pain who are likely to transition to chronic pain," said Schabrun. "If these brain biomarkers can predict that occurrence in future, we hope to be able to interfere with the transition to chronic pain to provide better patient outcomes."