Visual–vestibular function in patients following an acoustic neuroma resection

Abstract Problem: Clinical evidence suggests a relationship between visual and vestibular function; however, little work has specifically targeted how visual deficits integrate with vestibular function to affect functional balance in postoperative acoustic neuroma patients. Methods: Visual, audiometric, and balance functions were tested in 24 participants (mean age, 46.17 ± 13.107) who were placed into 2 groups: 8 acoustic neuroma patients at least 6 months post a vestibulo-neurosection (PVN), and 16 age-matched controls (NN). Variables of interest included: near and far visual acuity (ACU) using standardized Snellen charts, pure tone averages at 1,000/2,000 Hz (AUD1000 and AUD2000), horizontal and vertical Vestibular Ocular Reflex (VOR) gain (Gain), phase (PHZ), and symmetry (SYM). In addition, functional balance was measured using the combined balance scores from the EquiTest™ Smart Balance Master protocol for Sensory Organization Test (SOT) and lateral bias of the center of pressure (X-bias). All tests were assessed specifically to each side tested (right vs left). Results: Nonparametric statistics using a Kruskal-Wallis H analysis revealed a significant difference in right and left visual acuity: right = 57.86 ± 13.309 vs 170.63 ± 55.985, P = 0.021; left = 72.50 ± 26.617 vs 201.25 ± 61.483; P = 0.050. In addition, there was a significant difference in horizontal VOR phase, 190.760 ± 2.2443 vs 198.225 ± 4.6931, P = 0.001. Balance scores also resulted in a significant difference, 79.27 ± 8.084 vs 66.13 ± 8.896, P = 0.002. All significance levels were tested using the Welch Robust Tests of Equality of Means at the 0.05 level. Conclusion: Results indicate that visual function was also significantly impaired in conjunction with deficits in balance and auditory function in the PVN group compared to the NN group. Significance: These results will aid in developing rehabilitation strategies for functional balance training for patients post an acoustic neuroma resection. Support: Supported in part by a grant from the School of Allied Health in the University of Kansas Medical Center.