Correlation between palpatory assessment and pressure sensors in response to postural trunk tests

Abstract

BACKGROUND: The evaluation of postural trunk muscle function is a critical component of clinical assessment in patients with musculoskeletal pain and dysfunction. Postural activation of the trunk muscles has been evaluated by various methods. This study evaluates the correlation between subjective assessment of postural trunk muscle function with an objective measurement of abdominal wall expansion. METHODS: Twenty-five healthy participants (16 women, 9 men, age 22.4 years) were assessed. The subjective assessment was performed by two experienced Dynamic Neuromuscular Stabilization (DNS) clinicians evaluating the quality of trunk stabilization using five postural stability tests through palpation and observation. Interrater reliability was determined using an intraclass correlation coefficients (ICC). Objective measurement was performed using a new device (DNS Brace) which externally measures abdominal wall pressure. Spearman rank correlations were calculated for both palpation and observation measures with DNS Brace data. RESULTS: The interrater reliability (ICC2,k) estimates demonstrated moderate reliability in palpation measures for three DNS tests: Hip flexion test, Diaphragm test, & Intra-abdominal pressure regulation test (IAPRT) (ICC = 0.645–0.707). For observation measures, good reliability was found in IAPRT (ICC = 0.835), and three tests demonstrated moderate reliability: Hip flexion test, Diaphragm test, & Breathing Stereotype (ICC = 0.577–0.695). Correlation analysis demonstrated several moderate to strong correlations between palpation and DNS brace values (Assessor 1): IAPRT, rs= 0.580, p= 0.002, Diaphragm test, rs= 0.543, p= 0.005, (Assessor 2): IAPRT, rs= 0.776, p< 0.001, Breathing Stereotype, rs= 0.625, p= 0.001, Diaphragm test, rs= 0.519, p= 0.008, Hip Flexion test, rs= 0.536, p= 0.006, and Arm Elevation test, rs= 0.460, p= 0.021. For observation, several moderate correlations were demonstrated with DNS brace values (Assessor 1): Arm Elevation test, rs= 0.472, p= 0.017, (Assessor 2) Diaphragm test, rs= 0.540, p= 0.005, IAPRT rs= 0.475, p= 0.016, Hip Flexion test, rs= 0.485, p= 0.014, and Arm Elevation, rs= 0.451, p= 0.024. CONCLUSION: Based on inter-rater reliability and DNS brace correlations with trained DNS professionals, the IAPRT, Diaphragm test, and Hip Flexion test may prove useful when assessing asymptomatic individuals. More research is needed in order to establish the utility of DNS brace and clinical testing both in asymptomatic and back pain populations. DNS tests must be supplemented by further examinations for definitive clinical decision making.