An inertial sensor-embedded virtual reality (VR) head-mounted display, the Oculus Rift (the Rift), monitors
head movement so the content displayed can be updated accordingly. While the Rift may have potential
use in cervical spine biomechanics studies, its accuracy in terms of cervical spine mobility measurement
has not yet been validated. In the current study, a VR environment was designed to guide participants to
perform prescribed neck movements. The cervical spine kinematics was measured by both the Rift and a
reference motion tracking system. Comparison of the kinematics data between the Rift and the tracking
system indicated that the Rift can provide good estimates on full range of motion (from one side to the
other side) during the performed task. Because of inertial sensor drifting, the unilateral range of motion
(from one side to neutral posture) derived from the Rift is more erroneous. The root-mean-square errors
over a 1-min task were within 101 for each rotation axis. The error analysis further indicated that the
inertial sensor drifted approximately 61 at the beginning of a trial during the initialization. This needs to be
addressed when using the Rift in order to more accurately measure cervical spine kinematics. It is
suggested that the front cover of the Rift should be aligned against a vertical plane during its initialization.
& 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license