Researchers Demonstrate Efficacy of EEG-Based Test for Measuring Pain

Patients who visit the emergency department for pain are often asked to categorize their pain level using a visual scale of numbered faces. However, a recent study suggests the efficacy of a more empirical approach, through the use of an electroencephalography (EEG)-based test, that would be beneficial for both patients and physicians.

The study, conducted by researchers at Brown University, evaluated the efficacy of the EEG test for preclinical screening in animals, with the use of 3 pain medications—Lyrica, an FDA-approved treatment for chronic pain; a pain medication in phase 2 clinical trials; and a medication with inconclusive efficacy based on previous studies. The test was intended to objectively measure pain by measuring brain activity with electrodes placed on the scalp, according to the researchers.

“More than 15% of adults in the United States suffer from chronic pain. Ineffective therapies and narrow therapeutic windows of available drugs are contributing to the opioid epidemic. The scant success rate of drug development is partly attributed to poor translatability of analgesic efficacy in pre-clinical models, which is based predominantly on behavioral assays,” explained the authors.

The researchers explained how pain and the effectiveness of pain medications in animals have previously been determined by poking an animal’s paw and measuring how quickly it moves its paws away—slower withdrawal is associated to less pain and more effective medication. The traditional test for animals, the EEG test, and the blood concentrations of the medications, were to the clinical blood concentration of the medications in human patients.

The results of the EEG demonstrated similar results for all 3 medications. Carl Saab, PhD, associate professor of neuroscience and neurosurgery at Brown University and Rhode Island Hospital and coauthor, noted that the EEG tested provided more accurate results with certain experiments, such as those involving a dose below the effective level of the first medication. Also, the EEG demonstrated a decrease in theta power measurement at the clinical dose but not the low dose, and the behavior test demonstrated slower paw withdrawal at the low dose and the clinical dose, according the research.

“Our goal is to associate specific brain activity with various scores on the numerical scale to make pain assessment more objective. We want to help patients with chronic pain and their physicians get into agreement about pain level so it is better managed and diagnosed, which may reduce the over-prescription of opioids,” Saab said in a statement.

The researchers suggest that these findings should be helpful in the development of more effective pain medications and for improving the diagnosis and management of chronic pain.

Reference

Koyama S, LeBlanc BW, Smith KA, et al. An electroencephalography bioassay for preclinical testing of analgesic efficacy. Scientific Reports. 2018;8(1). doi: 10.1038/s41598-018-34594-2.