HSC Section 8_April 2017

A Comparison Between Wireless CROS and

Bone-anchored Hearing Devices for Single-sided

Deafness: A Pilot Study

*Jennifer Finbow, *

†

Manohar Bance, *Steve Aiken,

‡

Mark Gulliver,

‡

Janine Verge, and *Rachel Caissie

*Dalhousie University, Halifax;

QEII Health Sciences Center, Halifax; and

Nova Scotia Hearing and Speech

Centres, Halifax, Nova Scotia, Canada

Introduction:

This study compared wireless Contralateral

Routing of Signals (CROS) hearing aid and bone-anchored

hearing device (BAHD) in patients with single-sided deafness.

Methods:

Eight adults with single-sided deafness previously

implanted with a BAHD were given a 2-week trial with a CROS

hearing aid and tested in unaided and aided conditions. Both

devices were compared on head shadow effect reduction, speech

perception measures in quiet and in noise, self-assessment

questionnaires, and daily diaries.

Results:

Both the CROS and BAHD significantly reduced the

head shadow effect. QuickSIN scores were significantly better

with noise presented to the poorer ear, as compared to the better

ear, for the unaided condition, the BAHD, and the CROS.

Scores showed no significant differences between the CROS

and BAHD with noise presented to the better ear, but scores

with the CROS were significantly poorer than in the unaided

condition with noise presented to the poorer ear. There were

no significant differences between BAHD and CROS for the

ratings on the Bern Benefit in Single-Sided Deafness and

Speech Spatial Qualities questionnaires. Both devices were

worn an average of 10 hours per day. Four participants pre-

ferred the CROS for sound quality; three preferred the BAHD

for comfort.

Conclusion:

Comparisons of CROS and BAHD need to be

re-evaluated as both technologies have evolved. In our pilot

study, both devices seem comparable, with the CROS avoid-

ing the risks of surgery, and we recommend a trial of CROS

in our center for first line treatment of single-sided deafness.

Key Words:

BAHD

Bone-anchored hearing device

Contralateral routing of signals

CROS

Single-sided deafness

Unilateral hearing loss.

Otol Neurotol

36:

819

825, 2015.

Unilateral sensorineural hearing loss or single-sided

deafness (SSD) results in several communication diffi-

culties particularly in noisy situations (1). These diffi-

culties stem from the loss of binaural hearing and the head

shadow effect, in which the good ear is shielded from

sounds from the side of the poorer ear (2).

Currently, there are two main intervention methods

(SSD aids) used worldwide to help alleviate the head

shadow effect: the Contralateral Routing of Signals (CROS)

hearing aid and the bone-anchored hearing device (BAHD),

which routes sound to the better ear by transcranial bone

conduction from a microphone/processor attached to an

osseointegrated implant in the skull on the poor hearing

ear side. Neither restores hearing to the affected ear, but

rather alleviates the head shadow effect. Other, newer

interventions for SSD include cochlear implantation (3,4)

and the SoundBite (5). These devices will not be dis-

cussed in this article.

For several decades, the CROS was the traditional in-

tervention approach, with older CROS models consisting

of an analog hearing aid on each ear connected together

by a wire along the neck of the patient (6,7). Newer

CROS models are wireless and new CROS and BAHD

models include more sophisticated digital noise reduction

and adaptive directional microphones (8,9). Previous

studies have compared older models of CROS to older

models of BAHD, but both technologies have improved

substantially, especially the CROS.

It is well established that the CROS and BAHD do not

improve sound localization abilities for people with SSD

(10

18). However, the benefits of the devices for the

improvement of communication are not as well under-

stood, as indicated by conflicting results in the literature.

Address correspondence and reprint requests to Rachel Caissie, Ph.D.,

Associate Professor, School of Human Communication Disorders,

Dalhousie University, 1256 Barrington St., 6th floor, P.O. Box 15000,

Halifax, Nova Scotia, B3H 4R2, Canada; E-mail:

rcaissie@dal.ca

The authors report no conflicts of interest.

Source of Funding: Nova Scotia Health and Research Foundation.

Otology & Neurotology

36:

819

825 2015, Otology & Neurotology, Inc.

Reprinted by permission of Otol Neurotol. 2015; 36(5):819-825.

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