Computerized pain algesimetry may offer a standardized approach for quantitatively assessing cervical pain following whiplash injuries, researchers based in Germany report. Their findings also show that processes of early sensitization in whiplash injuries may occur peripherally as well as centrally.

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 December issue of Cephalalgia.

They used a computer-interactive pressure algesimeter to standardize cervical pain measurement in 23 drivers who had a whiplash injury 7 days earlier in a rear-end collision, and 24 healthy control subjects. A constant pressure of 1310 kPa was applied to the left and right splenius muscle and to the left and right trapezius muscle.

“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 AMN Health.

Specifically, they observed a steep rise of the pain intensity-time function indicating raised pressure pain in the patient group but not the control group. Maximal muscle pressure pain was significantly increased for both the left and right splenius muscles and the left trapezius muscles compared with the control group. The tolerance threshold was also reached more rapidly within the whiplash group.

When subjects were retested, Dr. Nebel said, 10% to 20% 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.

Cephalalgia 2004;24:1067-1075.