Bimodal Zoom

Rationale:

Cochlear implantation (CI) has become standard practice to

restore hearing in severely hearing-impaired patients by

providing multi-channel electrical stimulation to the

auditory nerve. Although CI-patients can achieve high levels

of speech recognition in quiet, speech recognition in noise

still remains one of the most challenging tasks. One way to

improve performance in noise is to benefit from binaural

hearing (hearing with two ears). For individuals with

residual contralateral hearing, a CI in one ear can be

combined with an acoustic hearing aid (HA) in the other ear.

This is known as bimodal hearing. For individuals without

residual hearing a second CI can be an opportunity in the

rare case. This is known as bilateral hearing.

A second way to improve speech recognition in noise is to

improve the quality of the signal before it is offered to the

ear. To that end directional microphone systems are

designed as they focus on the speech signal in front and

reduce the noise from other directions. Nowadays,

directional microphone algorithms are available for HA’s as

well as for CI’s. Both approaches (binaural hearing and

directional systems) are considered complementary,

however they are not yet evaluated conjointly.



Objective:

Evaluate the performance of directional microphone systems

in binaural (bimodal and bilateral) cochlear implant users



Study population:

One group consists of users of a cochlear implant (CI) in one

ear and a conventional hearing aid (HA) in the other ear.

The other group consist users of a cochlear implant (CI) in

both ears.



Study design:

A cross-over repeated measures design is carried out to

single-blind evaluate the performance of directional

microphone systems. During two test sessions bimodal

subjects are provided with the latest speech processor for the

CI ear and a state-of- the-art hearing aid in the other ear. The

bilateral group will be provided with the latest CI speech

processor in both ears during a single test session. Both CI

and HA devices allow different microphone configurations:

standard omnidirectional processing and directional multi-

microphone processing in each ear separately (monaural) or

combined cross ears (binaural). For each directional setting,

speech perception in noise is assessed using two different

masking materials (stationary noise versus fluctuating

talker).

Primary study parameter:

The primary outcome is the effect of microphone

configuration on speech recognition performance in noise.

Secondary study parameters:

Secondary outcomes in this study are bimodal benefit, the

effect of masker type and listening effort. Results between

the two patient groups, bimodal versus bilateral, will be

compared.

Nature and extent of the burden and risks associated with

participation, benefit and group relatedness:

There are no known health risks associated with

participation in this study. CE-marked hearing devices (CI and HA) are used within the scope of standard care.

Participation however takes time, effort and attention from

subjects. As a result of the study subjects can be advised

towards the use of a directional microphone setting to

improve their speech recognition performance in noise.

Amendments 23-aug-2016

For cochlear implanted (CI) patients speech recognition in

noise still remains one of the most challenging tasks. One

way to improve performance in noise is to benefit from

binaural hearing (hearing with two ears). For individuals

with residual contralateral hearing, a CI in one ear can be

combined with an acoustic hearing aid (HA) in the other ear,

known as bimodal hearing. For individuals without residual

hearing a second CI can be an opportunity in the rare case.

This is known as bilateral hearing.

A second way to improve speech recognition in noise is to

improve the quality of the signal before it is offered to the

ear. To that end directional microphone systems are

designed as they focus on the speech signal in front and

reduce the noise from other directions. Nowadays,

directional microphone algorithms are available for HA’s as

well as for CI’s. Both approaches (binaural hearing and

directional systems) are considered complementary, however they are not yet evaluated conjointly.

Therefore the hypothesis assessed in this study is that

directional microphone systems can improve speech

recognition performance in binaural (bimodal or bilateral)

cochlear implant users.

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During two test session bimodal subjects are provided with the latest speech processor for the CI ear and a state-of- the-art hearing aid in the other ear. The bilateral group will be provided with the latest CI speech processor in both ears during a single test session. Both CI and HA devices allow different microphone configurations: standard omnidirectional processing and directional multi-microphone processing in each ear separately (monaural) or combined cross ears (binaural).