Comparison of Subjective Perception of Balance to Ocular Counter Roll in Veterans

Abstract

Common symptoms of vestibular dysfunction are dizziness, nausea, feelings of vertigo as well as imbalance. Since these symptoms occur in many disorders, vestibular disorders are often under diagnosed in primary care settings (Grill, 2014). Vestibular dysfunction can lead to a greater difficulty in daily tasks and increase the risks of falls. While there are many risk factors for falls, loss of vestibular function greatly increases fall risk. We have previously assessed vestibular function in healthy adults from 21–97 by measuring ocular torsion (OT), a reflexive eye movement in response to body tilt (Serrador, 2009). Age was related to a significant reduction in OT. In addition, lower OT was strongly correlated with increased postural sway that has previously been found to predict fall risk. Previous literature has shown that veterans exposed to blasts and head injuries demonstrate vestibular symptoms, making veterans an ideal model to test for vestibular dysfunction. In the current study, we explored vestibular hypofunction by comparing ocular torsion (OT), an objective measure of otolith function, to a subjective perception of balance in veterans who have been exposed to blast and had head injuries as well as those who have not.25 veterans (19 males; 6 females) from different conflicts volunteered for this study, ages 26–70 (mean age 52 ± 13.12). To measure ocularcounter roll, subjects were rotated ±25 deg in the roll plane while theirocular torsion was assessed using eye‐tracking goggles. For subjective perception of balance, participants were asked to complete several surveys about their balance and dizziness. The surveys consisted of an “Activities‐Specific Balance Confidence Scale”, “Dizziness Handicap Inventory” and “Vertigo SymptomScale”. 14 veterans were found to have low OT (below .14 degrees) while 11 were found to have normal ocular torsion. Out of the 14 veterans that were found to have low OT, 12 did not report having any balance issues or in conveniences during their day‐to‐day tasks across the various surveys used. A linear regression was run between the otolith function and questionnaires (R2 = .201, p=. 224). Interestingly, despite the lack of correlation, some questions, for example “riding an escalator without holding the rail”, showed a better correlation to the OT value, consistent with a task that would require otolithinputs. These data suggest that the self‐report questionnaires assessing balance function do not appear to provide a good assessment of otolith hypofunction. Thus future work is necessary to develop a questionnaire that would better assess otolithhypofunction.