Assessment of the Reliability of a Laser-Based Visuomotor Feedback Device for Assessing Head Movement Control in...

Chronic neck pain is often associated with impaired cervical proprioception and motor control. Laser-based visuomotor feedback systems have emerged as promising tools to assess and retrain cervical function; however, their reliability properties remain underexplored. This cross-sectional study aimed to evaluate the intra-rater test-retest reliability of a laser-based feedback device for assessing head movement control in individuals with chronic neck pain.

To assess proprioceptive control and head movement precision, a custom-built laser-based visuomotor feedback device was employed. Thirty participants with chronic neck pain, aged between 25 and 65 years, who were referred to Esteghlal Physiotherapy Clinic in Tehran, completed two identical test sessions, 24 h apart. Each participant performed three trials for each of four predefined head movement paths (1-1, 2-2, 3-3, and A-G) using a laser pointer mounted on the forehead, which projected a beam onto a screen. Movement speed and success (percentage of path completed without deviation) were recorded. Intraclass correlation coefficients (ICCs) with 95% confidence intervals, standard error of measurement (SEM), and minimal detectable change at 95% confidence (MDC95) were calculated for speed and success metrics to assess test-retest reliability.

The device demonstrated good to excellent reliability. ICC values for speed ranged from 0.868 to 0.958 across all paths, and for success from 0.753 to 0.963, with all p-values < 0.001. Paths 2-2 and 3-3 showed the highest reliability for both metrics. Averaging across both sessions slightly improved consistency, suggesting a benefit in multi-day assessments. For averaged measures, SEM for speed ranged 0.065-0.122 s/cm (MDC95 0.180-0.339 s/cm) and SEM for success ranged 7.71-19.08 mm (MDC95 21.37-52.90 mm), with the largest absolute error observed for success on the complex A-G trajectory.

The laser-based visuomotor feedback system demonstrated good to excellent reliability for assessing cervical motor control within a small sample of individuals with chronic neck pain recruited from a single clinical setting. The inclusion of absolute reliability indices confirmed the system's consistency and precision across different trajectories. These findings support its potential as a practical and reliable tool for both clinical assessment and research applications in sensorimotor control.