The CROM-VAS Test: A novel and reliable clinical test to assess immediate pain relief following treatment for movement-evoked neck pain

BACKGROUND: The CROM-VAS Test is a novel method to quantify immediate hypoalgesic treatment effects for neck pain by measuring the reduction in pain intensity (using a VAS) at the same (sub)maximal neck position (using a CROM device) before and after treatment. It is a novel test designed to quantify immediate pain relief following treatment, without the potentially confounding effects of simultaneous improvements in function.

OBJECTIVES: (1) To describe the CROM-VAS Test, (2) To assess reliability and absolute agreement of the CROM-VAS Test, and (3) To evaluate its distinctiveness by comparing it to changes in pressure pain threshold (PPT) and baseline pain scores.

DESIGN: Cross-sectional study.

METHODS: The CROM-VAS Test was assessed in 58 people with non-specific neck pain treated with cervical mobilisation and cervicothoracic manipulation. Inter-rater reliability (intraclass correlation coefficient (ICC 1.1)) and absolute agreement (standard error of measurement (SEM), minimal detectable change (MDC) and Bland-Altman limits of agreement (LoA)) were determined.

RESULTS: Reliability was high (ICC 1.1: 0.91 (95%CI: 0.85-0.95) for the CROM-VAS Test in the painful direction and 0.73 (95%CI: 0.54-0.85) in the non/least painful direction). Agreement was good (CROM-VAS Test (painful direction): SEM: 2.3 mm; MDC: 6.4 mm; LoA: 13.5 to 16.6 mm; CROM-VAS Test (non/least painful direction): SEM: 4.0 mm; MDC: 11.1 mm; LoA: 14.7 to 22.0 mm). Low or negative correlations were observed between CROM-VAS Test scores and changes in PPT and baseline neck pain scores.

CONCLUSION: The CROM-VAS Test has good clinimetric properties. It measures a distinct dimension of pain relief compared to PPTs and baseline pain scores.