Chronic pain is notoriously challenging for doctors to diagnose and treat, because patients tolerate and describe their pain differently. The National Institutes of Health uses six different pain scales to measure pain, ranging from the smiley faces of the Wong Baker Pain Scale to monitoring a patient’s grunts and grimaces. All six scales are highly subjective.
Researchers in Switzerland think there’s a better way. They’re developing a new tool – a “barcode”– that gives doctors a more scientific method to evaluate a patient’s pain level. A team from Ecole Polytechnique Federale de Lausanne (EPFL) used sensors, placed on different parts of the body, to monitor and measure the way a patient moves.
“Movement is an objective indicator of pain. You move differently if you’re in pain than you do if you’re completely healthy,” says EPFL scientist Anisoara Ionescu. “It’s important for doctors to be able to evaluate that pain as precisely as possible.”
The EPFL study monitored the physical activity of 60 patients suffering from chronic pain and those of 15 healthy subjects who were pain-free. Sensors equipped with gyroscopes and accelerometers were attached to their chests, knees and ankles to measure movements and periods of rest. Not surprisingly, the researchers found that chronic pain patients moved differently than the healthy ones and that their active periods were marked by frequent intervals of rest.
Researchers collected data from the sensors over a period of several days to assess each patient’s activity level while walking, running, sitting and lying down. They used that data to develop a visual tool, a barcode for each patient that doctors can use to assess their pain.
“Eventually, the doctor could use this physical activity barcode to help make a diagnosis, better target a therapy, evaluate its effectiveness, and adapt it appropriately over time,” said Dr. Eric Buchser, a professor at a hospital in Morges, Switzerland who has been working with EPFL scientists for several years. “There is definitely a difference in behavior between healthy and chronically ill patients. But we’re just starting to collect data. We still need to gather more and establish objective reference values between patients.”
The study by EPFL’s Laboratory of Movement Analysis and Measurement appears online in the journal PLoS One .