Facing the pain

If you’re one of those people who hate blood tests, looking at your arm might reduce the pain you feel say researchers from the UK and Italy.

Researchers from UCL and the University of Milano-Bicocca, Italy found that simply looking at the body reduces pain.

A heat probe was placed in the left hand of 18 participants – the probe gradually increased in temperature – when the participants felt pain, they pushed a foot pedal to cut the heat. Participants always looked towards their left hand, but mirrors were used to manipulate what they saw – their hand or a wooden object.

Researchers found the pain threshold was about 3°C higher when participants looked at their hands. First author Flavia Manchini said: “The image that the brain forms of our body has a strong effect on the experienced level of pain. Moreover, the way the body is represented influences the level of pain experienced.”

Next the hand was either enlarged or reduced in size using concave or convex mirrors. When the hand was seen as enlarged, participants could tolerate greater levels of heat from the probe before reporting pain, suggesting the experience of pain arise in parts of the brain that represent the size of the body.

The results suggest that the scientists’ visual trick may have influenced the brain’s spatial map of the skin, and that the processing of pain is closely linked to these.

“Many psychological therapies for pain focus on the painful stimulus, for example by changing expectations or by teaching distractions techniques,” said Professor Patrick Haggard. “However, thinking beyond the stimulus that causes pain, to the body itself, may have novel therapeutic implications.”

“For example, when a child goes to the doctor for a blood test, we tell them it will hurt less if they don’t look at the needle,” he continued. “Our results suggest that they should look at their arm, but they should try to avoid seeing the needle, if that’s possible!”