Pressure Pain Threshold Testing Demonstrates Predictive Ability in People With Acute Whiplash

Abstract

Estimation of prognosis after acute trauma is an important concern for clinicians and rehabilitation funders. It has recently been estimated that approximately 50% of people with acute whiplash-associated disorder (WAD) will experience persistent disability, representing a significant direct and indirect cost on the individual and the community.2 The optimal clinical approach to treat acute T T STUDY DESIGN: Longitudinal cohort study. T T OBJECTIVES:To determine whether pressure pain threshold (PPT), tested at 2 standardized sites, could provide additional prognostic ability to predict short-term outcomes in people with acute whiplash, after controlling for age, sex, and baseline pain intensity. T T BACKGROUND:PPT may be a valuable assessment and prognostic indicator for people with whiplash-associated disorder. The extent to which PPT can predict short-term disability scores has yet to be explored in people with acute (of less than 30 days in duration) whiplash-associated disorder in a clinical setting. T T METHODS:Eligible patients were recruited from community-based physiotherapy clinics in Canada. Baseline measurements included PPT, as well as pain intensity, age, and sex. Neck-related disability was collected with the Neck Disability Index 1 to 3 months after PPT testing. Multiple linear regression models were constructed to evaluate the unique contribution of PPT in the prediction of follow-up disability scores. T T RESULTS:A total of 45 subjects provided complete data. A regression model that included sex, baseline pain intensity, and PPT at the distal tibialis anterior site was the most parsimonious model for predicting short-term Neck Disability Index scores 1 to 3 months after PPT testing, explaining 38.6% of the variance in outcome. None of the other variables significantly improved the predictive power of the model. T T CONCLUSION:Sex, pain intensity, and PPT measured at a site distal to the injury were the most parsimonious set of predictors of short-term neckrelated disability score, and represented promising additions to assessment of traumatic neck pain. Neither age nor PPT at the local site was able to explain significant variance beyond those 3 predictors. Limitations to interpretation are addressed.

Pressure Algometry: What Does It Really Tell Us?

“…5 More importantly, sensory responses indicative of augmented pain processing, such as cold hyperalgesia, have demonstrated predictive capacity to identify those likely to have poor functional recovery following whiplash injury, 4,7,9 resulting in recommendations that such measures be included in the assessment of people with acute WAD. 11 Walton et al 15 provide further data to support these findings by showing that pressure pain thresholds, measured at a site distal to that of the injury (over the tibialis anterior), also demonstrate predictive capacity. Lowered pain thresholds over uninjured body areas are considered to likely represent central phenomena.…”

“…These values have been provided for individuals with acute or subacute neck pain for 2 commonly tested sites, as well as information on confounders of age, sex, and pain intensity. 14 Three papers [13][14][15] in this issue of the Journal provide valuable information for the clinical use of pressure algometry in the assessment of patients with WAD. However, there are limitations to the information that can be gained by the measurement of pressure pain thresholds.…”

Reliability, Standard Error, and Minimum Detectable Change of Clinical Pressure Pain Threshold Testing in People With and Without Acute Neck Pain

“…This group has demonstrated both reliability 17 and predictive validity 16 of PPT testing over both the cervical spine and tibialis anterior sites under controlled experimental conditions. The results of this study and 2 related manuscripts 20,21 suggest that similar measurement properties and clinical phenomena are observable when testing is performed in circumstances more reflective of routine clinical practice.…”

Muscle Trigger Points, Pressure Pain Threshold, and Cervical Range of Motion in Patients With High Level of Disability Related to Acute Whiplash Injury

“…These sites have been previously used in investigation of acute and chronic WAD. 21,27,32,35,36 In addition, some studies conducted by Walton et al 42,43 support the clinical use of pressure algometry for assessment of pain sensitivity in patients with acute neck pain.…”