Pain Threshold Test Distinguishes Between Sincere, Feigned Pain
Studies comparing or combining this test with other methods of detecting pain malingering may yield a more comprehensive approach.
Patients feigning the severity of their chronic pain tend to have significantly increased warm sensation thresholds and decreased heat pain thresholds than patients who are sincere, according to research published in The Journal of Pain.
Additionally, when heat pain threshold tests were interrupted with sensory interference, feigned pain reports had significantly higher variability and poorer repeatability compared with sincere reports, Aaron Kucyi, PhD, from the Institute of Medical Science at the University of Toronto, and colleagues found.
“In clinical contexts, pain malingering can result in inappropriate allocation of therapeutic resources and distribution of treatments,” the researchers wrote. “In medicolegal contexts, deception about pain can result in inappropriate judgments and punitive measures, causing unnecessary emotional harm. Therefore, there is a strong need for development of tools that identify malingering and dishonest pain reports.”
Previous studies have shown that the percentage of patients who falsely report the severity of chronic pain in situations where there is financial incentive, such as when seeking compensation from an insurance company, is estimated to be between 20% and 50%.
For the current study, the researchers recruited 61 participants (27 men and 34 women) with a mean age of 25.9 ± 6 years from a college campus. They excluded patients with acute or chronic pain or any other conditions that might interfere with participants' ability to accurately report pain sensations, as well as those who had a formal medical background, ensuring that participants were unaware of the differences in sensations experienced by those with chronic pain.
The researchers tested warm sensation thresholds (WST) and heat pain thresholds (HPT) with thermal stimuli delivered with a Peltier-based computerized thermal stimulator (TSA II; Medoc, Ramat Yishai, Israel) with a 3 x 3-cm contact probe applied to the dorsal surface of the hand. A passage of current through the Peltier element produced temperature changes at rates determined by an active feedback system. The baseline temperature was set to 32°C with the rate of temperature change set to 2°C.