Reliability of 3D kinematic recording of jaw and head movements

The jaw and neck sensorimotor systems are functionally integrated during jaw functions1,2. The jaw border movements include maximum opening, laterotrusion to left and right, protrusion and retrusion3. Three-dimensional (3D) kinematic movement analysis provide data to distinguish natural movement patterns from those adapted to pain and dysfunction. Therefore, the reliability of kinematics is crucial to assess movement variability of integrated jaw-neck motor capacity. Can we ensure a high accuracy of the novel method intended to use for estimation of maximum jaw movements and geometric characterization (area and volume)? Is there a high test-retest reliability and intraindividual consistency for a group of healthy participants performing maximum jaw movements? 3D kinematic analysis was used for movement recognition. The first part included three glass beakers of different sizes, with known volumes and the cross-sectional area was estimated with a geometrical algorithm. The percentage deviation between target values and estimated values was calculated and to test the agreement a linear regression was made. The second part included 17 healthy participants (25.37 years ± 2.36). Maximum jaw movements were performed in a pre-determined movement pattern to track reflective marker positions of jaw and head segments. Movement amplitudes, magnitudes, areas, and volumes were analyzed. Intraclass correlation coefficient (ICC)4 estimates and Bland-Altman plots5 were used to assess test – retest reliability. Coefficient of variation (CV)6 tested the within session reliability. Preliminary results for the beakers showed a total percentage deviation from the target area and volume of 0.03 (SD 0.59) and 0.72 (SD 0.81), respectively. The linear regression showed a linear agreement between estimated and target value with R2=0.99. Preliminary results of test – retest reliability per movement outcome variable showed moderate to excellent reliability according to ICC-classification4. The limits of agreement between test and retest session presented with Bland-Altman plots showed good agreement between first and second measurement. The intra individual movement variability expressed as CV showed good repeatability. Jaw movements including the horizontal directions displayed widest ICC 95% confidence interval and highest CV values. (Fig. 1. Coefficient of variation - box plots).Download : Download high-res image (67KB)Download : Download full-size image This study addressed reliability of kinematic parameters of maximum jaw movements and its geometrics. The preliminary main findings indicate high accuracy of the novel method for estimations of volume and area. The agreement between sessions was considered good as well as consistency in repeated movements. Moreover, the more complex movement, the lower reliability and higher variability was seen. In future research of jaw-neck motor function the presented method is suggested to enables valid analysis of jaw movement performance.