2017 Sec 1 Green Book

Reprinted by permission of Laryngoscope. 2013; 123(6):1537-1546.

The Laryngoscope V C 2013 The American Laryngological, Rhinological and Otological Society, Inc.

TRIOLOGICAL SOCIETY CANDIDATE THESIS

Significance of Unilateral Enlarged Vestibular Aqueduct

John Greinwald, MD; Alessandro deAlarcon, MD; Aliza Cohen, MA; Trina Uwiera, MD; Keijan Zhang, PhD; Corning Benton, MD; Mark Halstead, MD; Jareen Meinzen-Derr, PhD

Objectives/Hypothesis: To describe the clinical phenotype of pediatric patients with unilateral enlarged vestibular aqueduct (EVA) and then to compare the findings to two clinically related phenotypes: bilateral EVA and unilateral hearing loss without EVA. In view of clinical observations and previously published data, we hypothesized that patients with unilat- eral EVA would have a much higher rate of contralateral hearing loss than patients with unilateral hearing loss without EVA. Study Design: Retrospective cohort study. Methods: Patients with unilateral or bilateral EVA were identified from a database of children with sensorineural hear- ing loss who were seen at a tertiary care institution between 1998 and 2010. Those with imaging findings consistent with well-established EVA criteria were identified. A comparative group of patients with unilateral hearing loss without EVA was also identified. The following specific outcome measurements were analyzed: 1) hearing loss phenotype, 2) laterality of EVA and hearing loss, 3) midpoint and operculum vestibular aqueduct measurements, and 4) genetic test results. Results: Of the 144 patients who met our inclusion criteria, 74 (51.4%) had unilateral EVA. There was a strong correla- tion between the presence of hearing loss and ears with EVA. Fifty-five percent of patients with unilateral EVA had hearing loss in the contralateral ear; in most of these patients, the hearing loss was bilateral. Contralateral hearing loss occurred in only 6% of patients with unilateral hearing loss without EVA. No significant differences were found in temporal bone meas- urements between the ears of patients with unilateral EVA and ipsilateral hearing loss and all ears with EVA and normal hearing ( P ¼ .4). There was no difference in the rate of hearing loss progression in patients with unilateral EVA between ears with or without EVA (16 of 48 [33.3%] vs. 9 of 27 [33.3%], respectively; P ¼ 1.0). There was no difference in the rate of hearing loss progression in patients with bilateral and unilateral EVA (41 of 89 ears [46.1%] vs. 25 of 75 ears [33.3%], respectively; P ¼ .1); however, both EVA groups had higher rates of progression compared to patients with unilateral hearing loss without EVA. There was a strong correlation between the presence of hearing loss at 250 Hz and the risk of more severe hearing loss and progressive hearing loss. Patients with bilateral EVA and SLC26A4 mutations had a higher rate of progression than patients who had no mutations ( P ¼ .02). No patients with unilateral EVA had Pendred syndrome. Conclusions: Children with unilateral EVA have a significant risk of hearing loss progression. Hearing loss in the ear contralateral to the EVA is common, suggesting that unilateral EVA is a bilateral process despite an initial unilateral imaging finding. In contrast to bilateral EVA, unilateral EVA is not associated with Pendred syndrome and may have a different etiology. Temporal bone measurements, hearing loss severity, and hearing loss at 250 Hz were all correlated with the risk of progressive hearing loss. Clinicians should become knowledgeable regarding the implications of this disease process so that families can be counseled appropriately. Key Words: Hearing loss, genetics, molecular biology. Level of Evidence: 2b. Laryngoscope, 123:1537–1546, 2013

INTRODUCTION Over the past two decades, abnormalities of the tem- poral bone have increasingly been recognized as an important etiology of sensorineural hearing loss (SNHL). 1– 4 Given that high-resolution computed tomography (CT) and magnetic resonance imaging have identified these abnormalities in up to 37% of children with previously unexplained SNHL, imaging has become an integral com- ponent of the standard evaluation of children with SNHL. 3,4 The most common finding revealed by imaging is an enlarged vestibular aqueduct (EVA); this is followed by abnormalities of the cochlea and the vestibular system. 5 Valvassori and Clemis were the first to describe a group of children with SNHL and concomitant EVA. 6 In a cohort of 3,700 patients who had undergone polytomo- graphic studies, these authors identified 50 patients with

From the Ear and Hearing Center, Division of Pediatric Otolaryngology, Cincinnati Children’s Hospital Medical Center ( J . G ., A . D ., A . C ., T . U ., J . M .- D .); Department of Otolaryngology–Head and Neck Surgery, University of Cincinnati College of Medicine ( J . G ., A . D ., J . M .- D .); Division of Human Genetics, Cincinnati Children’s Hospital Medical Center ( J . G ., K . Z .); Department of Radiology, Cincinnati Children’s Hospital Medical Center ( C . B ., M . H .); and Division of Biostatistics and Epidemiology, Cincinnati Children’s Hospital Medical Center ( J . M .- D .), Cincinnati, Ohio, U.S.A. Editor’s Note: This Manuscript was accepted for publication October 22, 2012. This project was funded in part by a State of Ohio Biotechnology Research Technology Transfer grant. The authors have no other funding, financial relationships, or con- flicts of interest to disclose. Send correspondence to John Greinwald, MD, FAAP, Ear and Hearing Center, Division of Pediatric Otolaryngology–Head and Neck Surgery, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Av- enue, Cincinnati, OH 45229. E-mail: John.Greinwald@cchmc.org

DOI: 10.1002/lary.23889

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