PP1417 - Sub-clinical Anxiety Does Not Affect Rotary Chair Measures of Vestibular Function in Young Adults

Abstract: Previous research reports an impact of anxiety on rotary chair measures, suggesting that vestibular assessments should consider patient anxiety levels in evaluation. However, these studies were conducted in individuals already diagnosed with clinical anxiety. In order to determine whether less severe anxiety might still affect vestibular assessments, in this study 39 participants age 18-30 (mean = 21.7 years, sd 3.35) completed a battery of anxiety, depression, and personality questionnaires as well as sinusoidal harmonic acceleration and velocity step testing. Results suggest these factors may safely be ignored in clinical vestibular assessment in young adult patients without clinical anxiety.

Summary: Rationale/Purpose
Rotational chair (RC) testing is used to evaluate, diagnose, and monitor vestibular dysfunction and is often part of a standard vestibular test battery. RC testing consists primarily of two components: Sinusoidal Harmonic Acceleration (SHA) and the Velocity Step Test (VST), with clinically relevant measures consisting of the gain, phase, and symmetry of the vestibulo-ocular reflex (VOR) in the horizontal plane (SHA) and VOR gain, time constants, and symmetry (VST).

Previous research found that SHA VOR gain is higher and the VST VOR time constant is shorter, in psychiatric patients with a primary diagnosis of anxiety. Anxiety and balance concerns are often linked behaviorally and, increasingly, anatomically. Since the high VOR gain and longer VST time constant seen in those with severe anxiety could mask the low gain and shorter time constants seen in typical vestibular dysfunction, it is important to determine if less severe levels of anxiety also impact VOR gain or Step Velocity time constant decay.

Methods
Thirty-nine young adults (ages 18-30 years, mean: 21.7; sd: 3.35; 28 women, 10 men, 1 non-binary) were tested under a protocol approved by the Purdue University Human Research Protection Program (IRB #2024-440). Following routine hearing screening and otoscopic examination, participants completed seven psychological assessments: Beck’s Anxiety Inventory (BAI), Beck’s Depression Inventory (BDI), Patient Health Questionnaire (PHQ-9), General Anxiety Disorder (GAD-7), two tests of personality, and the Situational Vertigo Questionnaire. SHA and VST testing were then conducted under “tasking” conditions in a quiet clinic room using a Micromedical Technologies System2000 Reclining Rotational Vestibular Chair with VisualEyes binocular goggles to record VOR gain, phase, and symmetry. SHA testing was conducted at the following frequencies: 0.01, 0.02, 0.04, 0.08, 0.16, 0.32, and 0.64 Hz, while VST testing was performed in both clockwise and counterclockwise rotations, at 100 dsp.

SHA gain was analyzed with a linear mixed effects model including all relevant parameters and their interactions with rotation frequency, and subject ID was included in the random effects structure. VST gain and decay were analyzed similarly, except that all testing was done at a single frequency, so this factor and its interactions were left out of the model.

Results & Conclusions
Participants showed a wide range of scores on each of the anxiety assessments, with excellent correspondence across tests for similar traits (e.g. anxiety). Anxiety scores ranged from none to moderately severe (e.g. 0 – 47 out of 63 on the BAI) but distributions were heavily skewed such that mean and median scores were in the mild to moderate range. No measures of anxiety or depression showed significant effects on either rotary chair measure examined. Subsequent equivalence testing analyses showed that rotary chair measures were statistically equivalent for different levels of anxiety, suggesting that anxiety may be ignored in clinical vestibular assessment as least for patients not already known to have clinical anxiety. Further research is necessary to determine whether any effect of anxiety or depression is observed in older and/or more psychiatrically affected populations, as well as in those with vestibular dysfunction.