A simple blood test could provide both definitive physical proof of repetitive stress injury and an early warning for potential victims.
New research points to measurable clues in the bloodstream, known as biomarkers, that can be used to gauge inflammation caused by carpal tunnel syndrome and other elusive soft-tissue injuries known as RSI.
A test for repetitive stress could validate the somewhat mysterious group of injuries, which are notoriously difficult to diagnose since doctors can't do much beyond asking patients where it hurts. A lack of physical evidence has created skepticism -- particularly among insurance companies -- about whether the condition actually exists. The new study shows that a blood test could provide early evidence of a problem.
"If there's a physical blood test that would indicate it, that may change the view of RSI," said Jane Bear-Lehman, associate professor of occupational therapy at New York University, who's familiar with the study.
Carpal tunnel syndrome gained a high profile in the '80s and '90s, with computer users suffering from pain in their hands, wrists and arms. Some cases are so severe that employees are forced to change careers and suffer chronic pain. Symptoms can include recurring pain in the neck, shoulders, wrists and hands, as well as tingling, numbness or weakness.
Skeptics, however, have questioned whether the condition is real, and some suspect it's largely related to stress. The new study could help end that skepticism. The findings suggest that when repetitive movements are beginning to cause inflammation, the immune system creates certain chemical biomarkers that indicate possible repetitive stress.
Researchers at Temple University tested the blood of nine healthy people and 22 volunteers who suffered from various types of repetitive stress injuries, such as carpal tunnel syndrome. In the injured patients, the researchers found high levels of biomarkers known to indicate inflammation. People with the most severe injuries had the highest level of biomarkers. The findings were published in the March issue of the journal Clinical Science.
The study is small, and its authors cautioned that they haven't necessarily found a new way to diagnose repetitive stress injuries. Still, the findings could at least confirm a problem or warn a patient to be more careful on the job.
In a press release, a study co-author warned that the biomarkers aren't a diagnostic test and could indicate other injuries. Even so, "they do provide a red flag where before there was none," said Ann Barr, associate professor of physical therapy at Temple University. The authors did not return phone calls requesting further comment.
Currently, therapists diagnose repetitive stress injuries by moving around a patient's wrist, shoulder or other body part and checking to see which positions cause pain, according to Bear-Lehman. "It's not like a fracture where it's clear, you have a date of injury and you can see in an X-ray what happened," she said.
To make matters more complicated, inflammation can change from day to day depending on a person's work schedule, meaning that an injury may not be detectable at certain times, she said: "Because of the kind of disease it is, it may not hurt today, but it hurts tomorrow."
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