Improving the diagnostic process by identifying patients with chronic pain based on how they respond to tests measuring their perception of pain can provide additional standardized outcomes for clinical trials. This is one of the first study to describe different observable characteristics of the psychophysical mechanisms involved in chronic pain in youth.
Goal
Studies have shown that chronic pain in children and adolescents may be associated with altered mechanisms in the body that can either facilitate or supress pain. However, a major limitation in treatment outcomes for chronic pain in youth is the diversity of the population, thus a treatment that could work on someone, might not work on everyone. The objective of this study led by Dr. Don Daniel Ocay and Dr. Catherine Ferland was to identify subgroups in a large population of pediatric patients with chronic pain based on their internal facilitatory (enhancing) and inhibitory (supressing) pain mechanisms.
Methodology
608 young patients with chronic pain and 60 healthy controls underwent a condition pain modulation paradigm where a 2-minute immersion of the left forearm in cold water (12°C) changes the pain perceived from a 2-minute constant painful heat stimulation.
Main findings
The patients were best divided into three groups: Group 1 and 2 were similar to healthy controls in regard to being characterized by efficient inhibitory pain mechanisms and lack of facilitatory pain mechanisms. However, they were characterized by high and low pain intensity reported during the cold immersion test, respectively. Patients in group 3 were characterized by high pain intensity during the cold immersion test, but also presence of facilitatory pain mechanisms and inefficient inhibitory pain mechanisms.
Take home message
The study shows that in a large sample of pediatric patients with chronic pain, there is diversity and differences in the way people respond to pain due to their different facilitatory and inhibitory mechanisms that makes their pain perception unique. It is important to take both into consideration in a single experimental model to give as much information as possible on subgroups of patients that may benefit from a specific therapeutic treatment.
