The results of the study exposed a significant patient gender bias that could lead to disparities in treatments.
The novel research published in the Journal of Pain was co-authored by Elizabeth Losin, assistant professor of psychology and director of the Social and Cultural Neuroscience lab at the University of Miami.
According to "Gender biases in the estimation of others' pain," when male and female patients expressed the same amount of pain, observers viewed female patients' pain as less intense and more likely to benefit from psychotherapy versus medication as compared to men's pain, exposing a significant patient gender bias that could lead to disparities in treatments.
The study consisted of two experiments. In the first, 50 participants were asked to view various videos of male and female patients who suffered from shoulder pain performing a series of range of motion exercises using their injured and uninjured shoulders. Researchers pulled the videos from a database that contains videos of actual shoulder injury patients, each experiencing a range of different degrees of pain. The database included patients' self-reported level of discomfort when moving their shoulders.
According to Losin, the study likely provides results more applicable to patients in clinical settings compared to previous studies that used posed actors in their stimuli videos.
"One of the advantages of using these videos of patients who are actually experiencing pain from an injury is that we have the patients' ratings of their own pain," she explained.
"We had a ground truth to work with, which we can't have if it's a stimulus with an actor pretending to be in pain," she added.
The patients' facial expressions were also analyzed through the Facial Action Coding System (FACS) -- a comprehensive, anatomically based system for describing all visually discernible facial movements. The researchers used these FACS values in a formula to provide an objective score of the intensity of the patients' pain facial expressions. This provided a second ground truth for the researchers to use when analyzing the data.
The study participants were asked to gauge the amount of pain they thought the patients in the videos experienced on a scale from zero, labeled as "absolutely no pain," and 100, labeled as "worst pain possible."
In the second experiment, researchers replicated the first portion of this study with 200 participants. This time, after viewing the videos, perceivers were asked to complete the Gender Role Expectation of Pain questionnaire, which measures gender-related stereotypes about pain sensitivity, the endurance of pain, and willingness to report pain.
Perceivers also shared how much medication and psychotherapy they would prescribe to each patient and which of these treatments they believed would be more effective in treating each patient.
The researchers analyzed the results of the participant's responses to the videos compared to the patient's self-reported level of pain and the facial expression intensity data. The ability to analyse observers' perceptions relative to these two ground truth measures of the patients' pain in the videos allowed the researchers to measure bias more accurately, Losin explained. That is because bias could be defined as different ratings for male and female patients despite the same level of responses.
Overall, the study found that female patients were perceived to be in less pain than the male patients who reported and exhibited, the same intensity of pain. Additional analyses using participants' responses to the questionnaire about gender-related pain stereotypes allowed researchers to conclude that these perceptions were partially explained by these stereotypes.
"If the stereotype is to think women are more expressive than men, perhaps 'overly' expressive, then the tendency will be to discount women's pain behaviours," Losin said.
Losin further noted, "The flip side of this stereotype is that men are perceived to be stoic, so when a man makes an intense pain facial expression, you think, 'Oh my, he must be dying!' The result of this gender stereotype about pain expression is that each unit of increased pain expression from a man is thought to represent a higher increase in his pain experience than that same increase in pain expression by a woman."
What's more, psychotherapy was chosen as more effective than medication for a higher proportion of female patients compared to male patients.
Additionally, the study concluded that the gender of the perceivers did not influence pain estimation. Both men and women interpreted women's pain to be less intense.
The idea to study disparities in the perception of pain based on a patient's gender was derived from previous research, Losin said, that found women are often prescribed less treatment than men and wait longer to receive that treatment as well. (ANI)