Assessing the Reliability of Smooth Pursuit Across Various Neck Postures Using a Custom Ocular Motor Detection System

Phase 1 Reliability and Performance Evaluation of a Custom-Made Oculomotor Detection System Across Multiplanar Neck Positions

The integration of cervical proprioceptive input, visual information, and vestibular signals plays an essential role in gaze stabilization and sensorimotor control. Previous studies have suggested that alterations in cervical afferent input may influence oculomotor performance and contribute to symptoms such as dizziness and impaired visual stability. However, most conventional smooth pursuit assessments have been restricted to a single rotational axis, primarily focusing on horizontal neck torsion positions and velocity-based parameters.

To address these limitations, a custom-made oculomotor detection system was developed to quantify smooth pursuit eye movements under multiple cervical orientations. The system was designed to evaluate eye movement performance across different neck planes, including neutral posture, lateral flexion, flexion-extension, and rotational positions. Multiple ocular motor parameters were incorporated to provide a multidimensional assessment framework, including pursuit Gain, Smooth Pursuit Neck Torsion Difference (SPNTD), Accuracy, and Latency.

The primary objective of this study was to evaluate the measurement performance and reliability of the custom-made system in healthy individuals. Specifically, the study aimed to determine the consistency of ocular motor parameters across repeated measurements and to investigate whether different neck positions influence smooth pursuit tracking performance. Reliability was assessed using intraclass correlation coefficients (ICC), while differences among cervical orientations were analyzed using non-parametric statistical methods.

The findings of this study established the technical feasibility and reliability of the custom detection system and provided preliminary normative data regarding ocular motor performance under multiplanar cervical conditions. These results support the use of the system as a research and clinical assessment tool for evaluating cervical-ocular sensorimotor interactions.

Phase 2 Characterizing Multidimensional Oculomotor and Cervical Sensorimotor Function in Individuals With Upper Mechanical Neck Pain

Mechanical neck pain (MNP) is a common musculoskeletal disorder that may be associated with disturbances in cervical sensorimotor integration. Although conventional clinical assessments such as cervical range of motion and joint position error testing are frequently used to evaluate cervical function, these measures may not fully capture subtle impairments in cervical-ocular sensorimotor control. Increasing evidence suggests that altered cervical proprioceptive input may influence eye movement control and contribute to visual disturbances, impaired gaze stability, and symptoms related to cervical dizziness.

Building upon the validated oculomotor detection system established in the preceding reliability study, the present investigation aims to explore multidimensional ocular motor function in individuals with upper mechanical neck pain. Unlike conventional smooth pursuit neck torsion assessments that primarily examine a single rotational plane, this study utilizes a multi-axis assessment framework to evaluate ocular motor performance across multiple cervical orientations. In addition to velocity-based measurements, spatial and temporal parameters are incorporated to provide a comprehensive characterization of oculomotor behavior.

Participants with upper mechanical neck pain and asymptomatic controls undergo assessments of cervical sensorimotor function, including cervical range of motion and joint position error testing, followed by ocular motor evaluations performed under seven different neck positions. Oculomotor performance is quantified using pursuit Gain, Smooth Pursuit Neck Torsion Difference (SPNTD), Angular Error, Pursuit Latency, and temporal synchronization parameters derived from cross-correlation analyses. These outcome measures are intended to capture complementary aspects of ocular motor control, including velocity matching, spatial tracking accuracy, torsion-related modulation, and temporal coordination.

The primary objective of this study is to identify ocular motor parameters that may distinguish individuals with upper mechanical neck pain from asymptomatic controls and to determine whether multidimensional oculomotor assessment provides additional information beyond conventional cervical measures. The study further seeks to investigate the influence of cervical orientation on ocular motor performance and to characterize potential alterations in cervical-ocular sensorimotor integration associated with mechanical neck pain.

Findings from this study are expected to contribute to a better understanding of cervical sensorimotor dysfunction and may facilitate the development of clinically useful biomarkers for identifying subtle oculomotor abnormalities in individuals with neck pain. Furthermore, the results may provide a foundation for future investigations involving patients with cervicogenic dizziness and other disorders characterized by impaired cervical-ocular sensorimotor control.

Inclusion criteria

• Age between 20 and 60 years.
• No history of significant neck surgeries.
• No history of corrective eye surgery.
• No skeletal muscle injuries or pain in the upper or lower limbs.
• Free from vestibular system-related disorders and neurological symptoms.
• Participants must avoid food and drink for 3 hours before the experiment.
• Participants should have 8 hours of sleep the night before the experiment.

Exclusion criteria

• Any participant who has undergone vision correction surgery in the last year.
• Any participant who has experienced significant head or neck trauma in the past year.
• Any participant with a history of vestibular system disorders or neurological symptoms.
• Participants who have used medications or alcohol for an extended period.
• Participants with abnormal pain in any part of the torso.
• Individuals suffering from claustrophobia.