The supportive touch of a romantic partner can have enormous benefits in coping with stressful, threatening, and especially painful situations. But, to date, the evidence in favor of a role for supportive touch in easing pain has been largely anecdotal.
Now, a new brain imaging study provides a detailed investigation of how the nervous system functions during supportive touch, enhancing the understanding of the influence of social factors on pain.
Research led by first author Marina López-Solà, Cincinnati Children’s Hospital, US, and Tor Wager, Dartmouth College, Hanover, US, shows that female study volunteers subjected to experimental heat pain reported lower pain intensity and unpleasantness when holding the hand of their male romantic partner.
The female volunteers also reported increases in emotional comfort and a higher perceived level of closeness with the romantic partner. And, evidence from functional magnetic resonance imaging (fMRI), a brain imaging technique, showed that handholding decreased activity in key brain regions known to regulate pain as well as stress and defensive behaviors.
“This is a study that clearly needed to be done,” said Siri Leknes, University of Oslo, Norway, who studies how the brain processes feelings such as pleasure and pain but was not involved in the current work.
“Most people will have experienced that somebody holding your hand or touching you in a supportive way helps in coping with aversive situations and so this study is a timely, systematic demonstration of this with a nice investigation of underlying mechanisms,” Leknes added, referring to the brain processes underlying this phenomenon.
The research appeared in the September 2019 issue of the journal PAIN.
Pain relief from handholding
Touch is an inherently social sense, important for promoting healthy physical and psychological development as well as bonding between individuals. Recent studies have shown that touch can reduce pain associated with medical procedures in babies and experimental pain in adult partners. But how handholding in particular affected pain remained unclear.
“I have always been fascinated by the psychological and brain mechanisms that mediate different forms of analgesia [pain relief],” Lopez-Sola explained. “At the time we were designing these experiments, very little was known about the effect of handholding on the perception of pain. We knew that there were reports to suggest that it worked, but there were no reports of the brain mediators of handholding analgesia [how the brain regulates pain relief from handholding], so we set about to investigate how it affected pain intensity, pain unpleasantness and the impact on the relationship between the couple,” she added.
The study consisted of two phases: a baseline phase and a handholding phase. Both phases were run in an identical manner except that during the baseline phase, the female partner held an inert rubber squeeze ball, while during the handholding phase, she held the hand of her male romantic partner.
Then, a painful heat stimulus (47° Celsius) lasting for 11 seconds was applied to the opposite forearm while the female was lying in an fMRI brain scanner. Following the painful heat, females rated how intense their pain was, as well as how unpleasant they found it. The researchers also recorded measures of emotional comfort such as perceived relationship quality and closeness to one another.
Handholding greatly reduced the reported pain intensity and pain unpleasantness from the heat in the female study volunteers, compared to holding the rubber squeeze ball. The females also reported greater emotional comfort along with a higher perceived relationship quality between the partners.
Together, the results showed positive consequences of sharing the burden of a painful experience with another person.
What was happening in the brain?
After looking at the brain scans of the females as they held the hand of their romantic partner, the researchers found that handholding reduced a pattern of brain activity that this group and others previously found to play a role specifically in physical pain, known as the Neurologic Pain Signature (NPS), compared to the baseline phase.
“The fMRI analysis more directly tied the subjective experience of analgesia with how the brain was modified during the process of painful stimulation in the presence of the handholding partner,” said López-Solà.
The researchers also found that additional brain regions were involved, as further in-depth analysis of the fMRI data revealed that handholding increased connections between the NPS and what is known as the default mode network.
The default mode network generally is active when a person is not engaged in any demanding cognitive task but is in a resting state. It’s closely associated with one’s “inner state” and self-referential thoughts such as the appraisal of incoming information to determine how it will affect a person (whether it’s good, bad, or dangerous, for instance), as well as with trying to gauge the thoughts of others.
Handholding reductions in pain were also associated with less activity in brain areas involved in defensive reactions and stress.
One of the questions raised by the study is whether handholding is just a distraction from pain. But holding the rubber squeeze ball didn’t reduce pain intensity or unpleasantness, nor did it reduce the NPS, compared to handholding. That suggests that something real is happening in the brain during handholding; the changes the researchers saw cannot be attributed to the distraction that handholding might cause.
Leknes suggests an additional experiment to learn more about the effects of the supportive touch of a romantic partner on pain.
“You can’t distinguish the effects of holding your partner’s hand versus holding a stranger’s hand based on the current results,” according to Leknes. “Another way to address the specifics of having your partner touching you would be to have them in the room not touching you, all of which could tell us more about the nature of touch and its influence.”
This story first appeared on the IASP Pain Research Forum and has been lightly edited for RELIEF.
Dara Bree, PhD, is a freelance science writer based in Boston, US.