HSC Section 8_April 2017

Reprinted by permission of Laryngoscope. 2017; 127(1):223-228.

The Laryngoscope V C 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Cochlear Implantation for Single-Sided Deafness: A Multicenter Study

Douglas P. Sladen, PhD; Christopher D. Frisch, MD; Matthew L. Carlson, MD; Colin L.W. Driscoll, MD; Jennifer H. Torres, MA, CCC-A2; Daniel M. Zeitler, MD

Objectives/Hypothesis: To report the preliminary outcomes of patients with single-sided deafness and asymmetric hearing loss undergoing cochlear implantation at two centers. Study Design: Retrospective review and prospective data collection. Methods: Patients with single-sided deafness who underwent cochlear implantation at two centers were included. Pre- and postoperative measures included monosyllabic word and sentence recognition in quiet for the ear implanted, and sen- tence recognition in noise in the best-aided bilateral condition. Results: Average monosyllabic word recognition scores in quiet improved significantly from 11.3% (standard deviation [SD] 15.6%) preoperatively to 48.7% (SD 24.2%) at the 3-month postactivation interval, although they did not increase signif- icantly between the 3-month and 6-month intervals. Sentence recognition scores in quiet increased significantly from 18.4% (SD 28.5%) preoperatively to 65.9% (SD 17.9%) at the 3-month postactivation interval, but not between the 3-month and 6- month intervals. Sentence recognition in noise in the best-aided bilateral condition increased from 59% (SD 16.3%) preopera- tively to 72% (SD 16.0%) at 6-months postactivation, though the difference was not statistically significant. Thirteen of the participants reported tinnitus prior to surgery. Of those, 12 reported that tinnitus was improved after implantation, and one reported that tinnitus was unchanged. Conclusion: Preliminary results suggest that speech recognition in a singly deafened ear is significantly improved after cochlear implantation, although speech recognition in noise measured in the bilateral condition remains the same at 6- months postactivation. Key Words: Cochlear implant, single-sided deafness, signal-to-noise ratio, tinnitus, speech understanding in noise, sud- den sensorineural hearing loss. Level of Evidence: 4. Laryngoscope , 00:000–000, 2016

INTRODUCTION Single-sided deafness (SSD) is characterized by uni- lateral hearing loss in the presence of normal or near- normal hearing in the opposite ear. Previous research demonstrates that SSD affects some 18.1 million people in the United States and significantly impacts quality of life, resulting in increased stress and a feeling of exclu- sion in social settings. 1–3 Those affected by SSD have decreased hearing sensitivity, degraded speech recogni- tion, and usually some degree of tinnitus. In fact, more From the Department of Otolaryngology–Head and Neck Surgery, Mayo Clinic ( D . P . S ., C . D . F ., M . L . C ., C . L . W . D .), Rochester, Minnesota; the Denver Ear Associates ( J . H . T .), Denver, Colorado; and the Department of Otolaryngology–Head and Neck Surgery, Virginia Mason Medical Center ( D . M . Z .), Seattle, Washington, U.S.A. Editor’s Note: This Manuscript was accepted for publication April 26, 2016. Presented in part as a poster at The American Academy of Otolar- yngology–Head and Neck Surgery Annual Meeting, Orlando, Florida, U.S.A., September 21–24, 2014. C . L . W . D . is a consultant for Advanced Bionics Corporation, Cochlear Corporation, and MED-EL GmbH. D . M . Z . is a consultant for Med-El Cor- poration and Cochlear Corporation. The authors have no other funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Daniel M. Zeitler, MD, FACS, Virginia Mason Medical Center, 1100 Ninth Avenue, Mailstop X10-ON, Seattle, WA 98101. E-mail: Daniel.zeitler@virginiamason.org

than 90% of adults who experience unilateral sudden sensorineural hearing loss (SSNHL) also report ringing in their ears. 4 Perhaps most disturbing among patients with SSD is the loss of binaural function affecting sound localization and speech understanding in complex listen- ing environments. Binaural hearing is the result of 1) binaural squelch: the ability of the brain to separate speech from noise, 2) binaural summation: redundancy of auditory input, and 3) the head shadow effect: the decrease in loudness as sound moves from one side of the head to the other. 5,6 Current treatment options for SSD consist of routing the signal from the impaired ear to the nor- mal hearing contralateral side using contralateral rout- ing of signal (CROS) aids/BiCROS aids or an auditory osseointegrated implant system. Previous research has demonstrated that both are effective to overcome head shadow effect and detect sounds from the affected side, although they do not restore binaural hearing because the brain only receives input from one side. 7–9 In fact, research in this area demonstrates that rerouting the signal to the normal hearing side provides little improve- ment in sound localization and modest improvement for understanding speech in noisy conditions. 7–9 Cochlear implants (CI) have been suggested as an alternative treatment option for individuals with SSD.

DOI: 10.1002/lary.26102

Sladen et al.: Cochlear Implantation for SSD

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