Inter-rater reliability of the dynamic neuromuscular stabilization diaphragm tests among individuals with non-specific low back pain and neck pain

Background: The Dynamic Neuromuscular Stabilization (DNS) diaphragm test and intra-abdominal pressure regulation test (IAPRT) are qualitative clinical tests that assess postural stability provided by the diaphragm. Objective: Evaluate the inter -rater reliability of the diaphragm test and IAPRT between an experienced and novice DNS clinician among individuals with non-specific low back pain (LBP) and neck pain. Methods: Forty-five participants with non-specific LBP and/or neck pain were assessed by an experienced and novice DNS physiotherapist in the diaphragm test and IAPRT, and scored on a visual analog scale (VAS) according to five different criteria. Results: Moderate reliability was noted when assessing LBP and neck pain patients in the diaphragm test and IAPRT (p < 0.001). Moderate reliability also existed when assessing only LBP (p < 0.001) or neck pain (p = 0.002, p = 0.009) independently. Patients with lower pain (NPRS score of 5 or < ) demonstrated lower intra-class correlation coefficients, yet still moderate reliability in the diaphragm test (p = 0.004) and IAPRT (p = 0.001). Patients with higher pain (NPRS score of 6 or > ) demonstrated greater intra-class correlation coefficients, with the diaphragm test resulting in good reliability (p < 0.001). Conclusions: The diaphragm test and IAPRT demonstrate moderate reliability between an experienced and novice DNS clinician when evaluating LBP and neck pain patients, with a greater degree of reliability noted in patients suffering from higher reported pain.