Taking the Bias out of Pain Diagnosis

Objective measures of pain could help alleviate inequitable medical treatment

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This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Broken bones, migraines and stomach aches have wildly different causes, yet patients with any of these conditions and more will be asked the same thing in the emergency room: “Please rate your pain on a scale of 1 to 10.”

Right now, health care professionals only have that one way to measure a patient’s pain, and it’s completely subjective. Subjectivity is a problem because people rank the same pain differently, which results in different medical care. Any test based on self-reporting is dependent upon good communication between patients and their medical professionals.

Yet, if the patient is unconscious, or has difficulty communicating, assessing pain may not even be possible. Additionally, communication can also be compromised by implicit bias—studies show that gender and race affect how the same pain is treated. In other words, the same numerical ranking might get treated differently, depending on the patient. But now, a pair of advances in technology could change this by giving physicians objective ways to measure patients’ pain.


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Bias based on gender is a widely acknowledged problem with articleafterarticle detailing the ways in which women’s pain is not taken as seriously as men’s. Women wait an average of 65 minutes in the ER, compared to men’s 49 minutes. Women are also more likely to be prescribed sedatives, whereas men are more likely to be prescribed painkillers.

Racial bias also plays a role in how patients are treated. One study found that white participants, including medical students, rated black patients’ pain as lower than their white counterparts for the same hypothetical injuries. Another report found that black children are less likely to be given painkillers following the removal of their appendix.

Two recent studies could help change this by giving patients and physicians tools that don’t hinge on their perceptions—one based on brainwaves, the other on a blood sample. Both tests were designed by researchers to provide creative solutions to the opioid crisis. However, these tests are more than a tool to combat opioid overuse; they decrease the potential for miscommunication between patients and their doctors.

For marginalized patients who are sometimes thought to be “hysterical” or “overreacting,” these tests could be the difference between receiving needed treatment and being rushed out the door. For disabled patients who are unable to communicate directly, these findings could finally mean their chronic pain gets addressed.

The first study, led by Carl Saab at Brown University and Rhode Island Hospital, is based on electroencephalography (EEG) recordings. EEG is a noninvasive way to measure brain activity by placing electrodes on a patient’s scalp. Saab and colleagues reported that pain in rodents can be determined by looking at brain waves of about 4–7 oscillations per second, called “theta” frequency. These theta waves increased in rodents experiencing mild pain, and decreased when these rodents were given a clinical doses of the painkiller Lyrica.

The second study, led by Alexander Niculescu at Indiana University, searched in the blood for markers of pain. The blood test takes a “fingerprint” of the blood, recording which molecules were present and in what quantities. By tracking dozens of molecules in patients reporting their pain levels, the researchers found that changes in the expression of some molecules correlated with the patients’ subjective experience of pain.

Some of these “biomarkers of pain” are the targets of existing drugs, including nonsteroidal antiinflammatories, antidepressants and vitamin B12. “We have been able to match biomarkers with existing medications, or natural compounds, which would reduce or eliminate the need to use the opioids,” said Niculescu. Simply put, this blood test lets doctors figure out what’s needed to bring biomarkers back to “normal” levels, improving patients’ pain management while decreasing the number of painkillers prescribed.

At present, both tests are still in the early stages of development. While these pain assessments are promising, they might not be realistic for everyone. For patients without health insurance, EEG monitoring costs hundreds or even thousands of dollars. Additionally, it requires a trained technician to interpret the results, which limits accessibility, especially in rural or other underserved areas. Similarly, turnaround time for blood tests often means that they are better suited for the treatment of chronic pain, rather than the urgent cases seen in the emergency room.

In spite of these caveats, both advances are promising. Both the blood- and brainwave-based tests could decrease miscommunication between patient and health care provider and reduce the disparities in current pain treatment. It’s not unreasonable to imagine a future where “please rate your pain on a scale of 1–10” is no longer the default diagnostic tool. Perhaps with an objective way to measure patients’ pain, we can expect more equitable medical care at last.

Jess Sevetson is a neuroscience PhD candidate at Brown University. She works with bioengineers to study neuronal activity in three-dimensional brain cultures. Outside of the lab, she is an avid reader, furniture refinisher and occasional backpacker.

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