Pain automatically activates facial muscle groups

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Pain automatically activates facial muscle groups

http://www.eurekalert.org/pub_releases/2008-10/uom-paa102708.php

Université de Montréal study on the facial responsiveness to pain

A study has found that people who facially express pain in a more

intense way are not exaggerating if their perception of a painful

stimulation is controlled. The study conducted by Miriam Kunz is

published in the November issue of Pain.

The study was conducted on 20 men and 20 women between the ages of 18

and 30. Kunz placed a heating device on their leg to provoke the

painful stimulus. During the test, Kunz asked the test subjects to

push a button when the heat became moderately painful as she filmed

their facial expressions.

" Individuals who react to pain with intense facial expressions are in

fact feeling more pain if we rely on quantitative verbal measures

independent of the painful experience, " says Kunz, a postdoctoral

student at the Université de Montréal Faculty of Dentistry,

Department of Stomatology, and the Institut universitaire de

gériatrie de Montréal.

However, they have a lower tolerance for pain. " All test subjects

with an intense facial reaction to pain estimated that the sensation

was " moderately painful " between 45 and 47 degrees Celsius, while

others had a higher threshold, " she says.

All individuals have a non-verbal mode of communication influenced by

culture, education, age, sex, etc. This mode relies on innate and

universal programming. That is why a blind child knows how to smile,

even if he has never seen his mother smile. " Pain, just like joy,

sadness, fear, surprise, anger and disgust automatically activate

certain muscle groups that make the expression appear on the face, "

says Kunz.