HSC Section 8_April 2017

The Laryngoscope

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:

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

than 90% of adults who experience unilateral sudden

sensorineural hearing loss (SSNHL) also report ringing

in their ears.

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.

From the Department of Otolaryngology–Head and Neck Surgery,

Mayo Clinic (

.), Rochester, Minnesota; the

Denver Ear Associates (

.), Denver, Colorado; and the Department of

Otolaryngology–Head and Neck Surgery, Virginia Mason Medical Center

(

.), 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.

. is a consultant for Advanced Bionics Corporation, Cochlear

Corporation, and MED-EL GmbH.

. 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

DOI: 10.1002/lary.26102

Sladen et al.: Cochlear Implantation for SSD

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

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