The context, particularly the empathy (or lack thereof) provided by the people present, modulates the perception of pain. An Inserm team from the Lyon Neuroscience Research Center has just shown which cerebral mechanisms are involved.
"The initial question arises from a frequent observation in hospital settings. Doctor and nurses know that their behavior can influence the extent to which their patients feel pain. Recognizing pain and showing empathy can reduce suffering," explains Camille Fauchon, a researcher in the central human pain integration team (NeuroPain) at the Lyon Neuroscience Research Center (Lyon/Saint-Etienne)*. Empirical observations eventually gave way to a scientific evaluation of the phenomenon.
Two steps were involved. First, the team sought to confirm the behavior observed in a formal context. They had to reproduce the behavior of healthcare providers who were either empathetic or non-empathetic, and test the effect on the perception of pain in healthy volunteers. Clearly, real patients could not be subjected to painful stimuli and negative comments about the pain they were experiencing. "We hired professional actors who enacted sentences written by psychotherapists in three categories: neutral, empathetic, or non-empathetic, with powerful key words. The comments were recorded. During the experiment, people subjected to calibrated painful stimulations would hear the “experimenters” speaking in the next room," specifies the researcher. The subjects, who rated their pain on a 100-point scale, were subjected to a stimulus equivalent to about 60 on the pain scale, which can be felt clearly but is tolerable. The result of the initial experiment was that empathetic language reduced the pain felt by about 12%. "This is absolutely significant," according to Fauchon. "Some medications have the same effect." On the other hand, negative language increased pain only slightly, or at least not in a significant manner. The researcher attributed this to a defense mechanism: subjects would stop listening in order to protect themselves.
A Brain Signature
Once the reality of the phenomenon was confirmed, the cerebral mechanisms affected by the healthcare providers’ language remained to be understood. That was the target of the experiment, published in Scientific Reports. This time, the subjects were placed in a functional MRI tunnel and subjected to the same painful stimulus. They heard the same empathetic, neutral, or non-empathetic comments in an audio headset, left on "accidentally."
To know where to look, the team referred to the cumulated knowledge, in NeuroPain or elsewhere, on the constitution of the conscious experience of pain. It is a result of the activity and interaction of several brain networks specialized in an array of tasks. At the first level, the "lowest," certain areas of the brain are responsible for receiving sensory signals (in this instance, nociceptive) coming from the environs of the stimulated area. This signal is then processed by "higher" networks devoted to attention, autobiographical memory, self-awareness, context exploration, and more. "These second- and third-level areas give the experience of pain its texture by integrating the cognitive, emotional, and context-dependent dimensions," according to Fauchon.
And the activities of these "higher" networks, especially the posterior cingulate cortex and the precuneus, are indeed what were modulated by the empathetic comments during the experiment. "This confirms that by changing the context to an empathetic attitude, the perception of pain is changed via the recruitment of high-level cerebral networks," concludes Fauchon.
The researcher has now launched a new project at NeuroPain as part of his exploration of empathy in the context of pain. He will explore how adults decipher the cries of newborn babies. Do they known how to differentiate between cries of pain and those simply expressing stress? How is that translated in the cerebral level.
*Inserm/CNRS/Université Saint Etienne-Jean Monnet/Université Claude Bernard Lyon Unit 1028