The Effect of Neck Pain on Cervical Kinematics, as Assessed in a Virtual Environment

Sang Bahat H, Weiss PL, Laufer Y. The effect of neck pain on cervical kinematics, as assessed in a virtual environment. Arch Phys Med Rehabil 2010;91:1884-90. Objective: To compare cervical kinematics during functional motion in patients with neck pain and in asymptomatic participants using a novel virtual reality assessment. Design: Clinical comparative trial. Setting: Participants were recruited from university staff and students, and from a local physical therapy clinic. Participants: Patients with chronic neck pain (n=25) and asymptomatic participants (n=42). Interventions: Not applicable. Main Outcome Measures: Kinematic measures (response time, peak and mean velocity, number of velocity peaks, time to peak velocity percentage) were sampled while participants were engaged in the virtual game. Group and motion direction differences were assessed with a 2-way repeated-measures analysis of variance, Tukey-Kramer testing, and contrast analysis when relevant. Results: Participants with neck pain had lower peak and mean velocities than the asymptomatic participants (P<.0001). They also demonstrated a greater number of velocity peaks, indicating impaired motion smoothness (P=.0036). No significant group differences were found for response time or for time to peak velocity percentage. Cervical rotations were significantly faster and smoother than flexion and extension movements (P<.05). The overall impairment percentage in velocity and smoothness of cervical motion in patients with neck pain ranged from 22% to 44% compared with asymptomatic participants. Conclusions: Velocity and smoothness of cervical motion were more restricted in patients with chronic neck pain than found previously. Unlike range of motion and other static measurements, these dynamic variables reflect functional cervical motion and therefore contribute to a better understanding of the impairment associated with neck pain. Because the ability to move quickly in response to external stimuli is a commonly occurring phenomenon, this deficit is highly relevant to clinical assessment and management.