A computerized pain assessment system may make it possible to establish a standardized way to quantify neck pain resulting from whiplash injuries, researchers in Germany report.

The clinical evaluation of pressure pain tends to be subjective and qualitative, Dr. Philipp Stude, of University of Essen, and his colleagues point out in their article, published in the medical journal Cephalalgia.

They used a computer-interactive pressure “algesimeter” to standardize neck pain measurement in 23 drivers who had suffered whiplash seven days earlier in a rear-end collision, and compared the readings with those obtained from 24 healthy “control” subjects.

The system applied a constant pressure to the left and right splenius muscle at the side of the neck and to the left and right trapezius muscle at the back of the neck and shoulder.

“We found increased pain expression parameters in the acute stage of whiplash injury, where the left trapezii muscles were more painful than the right ones, perhaps due to the drivers’ position in the car,” co-author Dr. Katrina Nebel told Reuters Health.

Specifically, they observed a steep rise of the pain intensity over time, indicating raised pressure pain in the patient group but not the control group. The tolerance threshold was also reached more rapidly within the whiplash group.

When subjects were retested, Nebel said, 10 percent to 20 percent of patients still had high levels of pressure pain 6 weeks after the trauma.

Her group is now “examining which factors might predict long-lasting symptoms” in whiplash injuries.

SOURCE: Cephalalgia, December 2004.