Smartphone Application with Virtual Reality Goggles for the Reliable and Valid Measurement of Active Craniocervical Range of Motion

Objective: This study aimed to determine the intra-rater and inter-rater reliability and validity of a hybrid device, combining virtual reality goggles, a magnetometer and an inclinometer application for smartphones, to measure craniocervical range. Summary of Background Data: Accurate evaluation of craniocervical range of motion is important for early detection of certain diseased conditions and monitoring the progress of interventions. The universal goniometer is widely used for the measurement but it requires experienced practitioners. Whether a combination of virtual reality goggles and smartphone applications can provide the same or better performance compared with the goniometer is still unknown. Methods: Forty-one healthy adults from the department of physical medicine and rehabilitation were recruited for craniocervical range examination (flexion, extension, side-bending to the right or left and rotating to the right or left) by using the hybrid device and universal goniometer. Using the hybrid device, repeated measurements were performed twice by a primary rater and once by a second rater. The primary rater also conducted a measurement using the universal goniometer in the same cohort. The intra-rater and inter-rater reliability (intra-class correlation coefficient (ICC)) were calculated using the two-way random effect model, whereas the validity was examined by the Pearson correlation coefficient and Bland-and-Altman plot. The interval between the first and second sessions of the measurement for intra-rater reliability was set at 30 min. Results: Excellent intra-rater (ICC ≥ 0.925) and inter-rater (ICC ≥ 0.880) reliability was noted for the hybrid device. The minimal detectable changes from intra-observer and inter-observer comparisons ranged between 4.12° and 7.42° in all six directions. The Bland-and-Altman plot revealed small mean differences (≤1.68°) between the hybrid device and universal goniometer. Both instruments had highly correlated measurements of craniocervical motion (r values ≥ 0.918). Conclusion: For healthy participants, excellent intra-rater and inter-rater reliability was noted for the hybrid device, and the measurements were consistent with the universal goniometer measurements. Future studies are needed to examine whether the device can perform similarly for patients with neck disorders.