Novel Clinical Assessment of Visual, Vestibular, Somatosensory, and Autonomic Function:Establishing Test Re-Test Reliability in a Healthy Population

Abstract

Introduction: Maintaining balance is a complex process involving the integration of information from the visual, vestibular, and somatosensory (VVS) systems, along with autonomic nervous system (ANS) function. Traditional assessments of these systems are often expensive, limited to specialised settings or focus on overall balance outcomes, potentially overlooking deficits in the individual systems. This study aimed to evaluate the test-retest reliability of a novel, fully portable clinical assessment tool designed to provide objective measures for individual components of the VVS system and ANS function. Methods: Twenty-eight participants (aged 20–88 years), with no comorbidities and meeting Australian physical activity guidelines, completed the protocol twice. The novel clinical assessment tool comprised of two systems: (1) a virtual reality-type headset incorporating eye-tracking to evaluate visual-vestibular function (smooth pursuit and voluntary saccades), and autonomic function (pupil light reflex); and (2) the Active Movement Extent Discrimination Apparatus (AMEDA) for somatosensory function. Reliability was assessed using two-way mixed-effects model (consistency type, single rater) Intraclass Correlation Coefficients (ICC 3,1) calculated in R-studio. The standard error of measurement (SEM) and minimal detectable change (MDC) was also calculated. Bland-Altman plots were utilised to visualise the agreement between two test repeats. Results: Each metric demonstrated at least moderate to good test re-test reliability: left and right AMEDA (ICC = 0.69 and 0.75), smooth pursuit (ICC = 0.67), voluntary saccades (ICC = 0.53), autonomic response delay (ICC = 0.80), parasympathetic function (ICC = 0.86), and sympathetic function (ICC = 0.89). Discussion: This study supports the reliability of a new, fully portable clinical assessment tool to assess VVS and ANS function. By demonstrating the reliability of this new streamlined tool for evaluating the VVS and ANS systems, the findings of this study has the potential to enhance clinical practice and research in falls prevention and balance rehabilitation.</p