Age-related cutoffs for cervical movement behaviour to distinguish chronic idiopathic neck pain patients from unimpaired subjects

The present study aims to develop age-dependent cutoff values in a quasi-experimental, cross-sectional diagnostic test study. One hundred and twenty (120) asymptomatic subjects (n = 100, 36a (TM) Euro, 18 75 years, for normative values; n = 20, 23-75 years, 15a (TM) Euro, for selectivity analyses) and 20 patients suffering from idiopathic neck pain (selectivity analyses, 22-71 years, 15a (TM) Euro) were included. Subjects performed five repetitive maximal cervical flexion/extension movements in an upright sitting position. Cervical kinematic characteristics (maximal range of motion (ROM), coefficient of variation (CV) and mean conjunct movements in rotation and flexion (CM)) were calculated from raw 3D ultrasonic data. Regression analyses were conducted to reveal associations between kinematic characteristics and age and gender and thus to determine normative values for healthy subjects. Age explains 53 % of the variance in ROM (decrease 10.2A degrees per decade), 13 % in CV (increase 0.003 per decade) and 9 % in CM (increase 0.57A degrees per decade). Receivers operating characteristic (ROC) analyses were conducted for differences between individual values of the kinematic characteristics and normative values to optimise cutoff values for distinguishing patients from unimpaired subjects (20 patients and 20 healthy). Cutoff values distinguished asymptomatic subjects' and chronic nonspecific neck patient's movement characteristics with sufficient quality (sensitivity 70-80 %, specificity 65-70 %). By including such classifications, the present findings expand actual research stating an age-related decrease in kinematic behaviour only using categorising span widths across decades. Future study is warranted to reveal our results' potential applicability for intervention onset decision making for idiopathic neck pain patients.