Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03897634 |
| Other study ID # |
SP0053453 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
August 30, 2019 |
| Est. completion date |
April 15, 2020 |
Study information
| Verified date |
May 2021 |
| Source |
Northwestern University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Despite improvements in digital hearing aid technology, many hearing aid users continue to
report difficulty understanding speech in challenging listening environments. Remote
microphones have been shown to provide benefit in the most common of these challenging
listening environments: distant speakers, background noise, and reverberation. Despite
demonstrated benefit, there is a low rate of remote microphone use among adult hearing aid
users. One reason for low uptake may be an uncertainty among hearing healthcare providers and
potential users regarding expected clinically relevant benefit. This clinical trial will
attempt the following:
1. To describe the range of remote microphone benefit among adults with mild-to-moderate
sensorineural hearing loss
2. To determine specific individual factors beyond the audiogram that are associated with
greater benefit from remote microphones
Description:
2.0 Background / Literature Review / Rationale for the study:
Even when wearing well-fit hearing aids, many individuals with hearing loss continue to
report difficulty communicating in background noise is one of the most common complaints of
individuals with hearing loss. Directional microphones can improve speech perception in
noise, but often fail to provide benefit in cases where the talker is distant from the
listener, where there are multiple or moving noise sources, or in reverberation. Digital
noise reduction may reduce listening effort and improve listening comfort, but has minimal
effect on speech perception.
Placing the microphone in close proximity to the talker reduces the effective distance
between speaker and listener, compensating for the effects of background noise and
reverberation on the target signal. Use of a remote microphone can significantly improve
signal-to-noise ratio (SNR), thereby improving speech perception in noise and at a distance.
Recent studies demonstrated that remote-microphone devices that utilize adaptive digital
technology (i.e, Roger) provide significantly more benefit for speech understanding in noise
than non-adaptive remote microphones. Those advantages are likely related to the adaptive
nature of the device, whereby the microphone gain varies according to the level of noise in
the environment. In addition, interference is reduced via transmission of short digital
bursts (160 μs) across a range of channels (2.4-2.4835 GHz). Further, the ability to utilize
the hearing aids' onboard directional microphones in conjunction with a remote microphone
gives listeners the benefits of remote microphone use without sacrificing nearfield
intelligibility. The Roger system has also been shown to improve cell phone communication
amongst cochlear implant patients.
Despite demonstrated advantages, use of remote microphone assistive devices among adults is
low. In a recent study of listeners with severe hearing loss-a group which has substantial
difficulty communicating in background noise, and is likely to receive significant benefits
from remote-microphone devices-less than 10% reported use of a remote microphone. While cost
may be a barrier for some users, even when such systems are available for free (as in the
Veterans Administration), use is still low. One reason may be uncertainty among both
providers and potential users as to expected benefit for a given listener. For example, Lewis
et al. failed to demonstrate a clinically-significant benefit of remote microphone use using
a work-life outcomes scale in a cohort of mostly nonworking (retired) participants. Wolfe et
al. found significant improvements in objective speech recognition on average, but with a
wide range of benefit (from 10% to 60% improvement across individual participants). That
study also suggested that individual factors may affect remote microphone benefit, in that
the magnitude of improved recognition was correlated with the ability to use spatial cues to
improve recognition.
Research Locations:
All study tasks will take place in the Hearing Aid Lab and/or Northwestern's Center for
Audiology, Speech, Language and Learning.
When testing in the Hearing Aid Lab, Frances Searle building room 1-451, we will either use
the sound booth or lab space. All hearing related tasks take place in a sound booth which is
a sound treated 8'x 8' room within the larger lab space. When taking histories or cognitive
measures we will use the office space located within the lab or an additional nearby (i.e.
same building) testing room. The additional test room is only used if participant
confidentiality can be maintained (i.e. conversation is not audible to those outside the
room). When using the Center for Audiology, Speech, Language and Learning all tasks will take
place in a sound proof booth, in a clinical Hearing Aid fit room, or the virtual sound
environment (ViSoR). ViSoR is a 16' by 14' by 9' space capable of simulating the acoustics
and background noise properties of any environment by using an array of speakers.
Approach
The trial will use a within-subjects design consisting of baseline assessment (see
assessments), hearing aid with Roger connect fitting, a four week trial period of use in the
participant's everyday environment(s), and outcome measures.
Participants who qualify for a dome fitting will start their trial the same day as their
baseline assessment. Participants who require a custom mold fitting will have earmold
impressions taken at their baseline assessment and then be fit with the trial devices after
the custom earmold has arrived back in the lab, usually about one week later. During an
earmold impression the ear is visually inspected with an otoscope (magnifying scope with
light). A cotton block and soft material are placed in the ear. The resulting impression
created by the soft material is used to order an earmold for later testing. This is a
standard clinical procedure.
A licensed clinical audiologist will perform the assessments, fitting and counseling of
hearing aids and Roger system, and conduct the outcome measures. To ensure appropriate fit
and use by the participants, there will be a follow-up one week after being fit with the
devices. During this appointment participants will be evaluated and their hearing aid logging
will be checked for compliance.
Hearing aid/Roger fitting: Trial hearing aids and clinically-appropriate earmolds or domes
will be provided by Phonak at no charge to the participants for the duration of the trial.
Those aids are expected to be drawn from Phonak's advanced technology level and to provide
datalogging via 7 base programs. Aids will be set to NAL-NL2 targets using probe microphone
measurements. Directional microphones will be enabled and verified via probe-microphone
testing. Roger will be verified via probe-microphone testing, following clinical best
practice. Appropriate hearing aid adjustments (as judged by the study audiologist) will be
permitted to provide acceptable sound quality and loudness. Final REARs will be recorded. The
study audiologist will instruct participants regarding hearing aid and Roger device use.
PHAST-R and a Roger competency questionnaire (to be developed with input from Phonak) will be
used to document understanding of device function at the fitting and one week follow-up
appointments. Participants will then wear the hearing aids and use the Roger system for 1
month in their everyday listening environments. At the completion of the trial, participants
will return to the lab for outcome assessments and to provide spontaneous feedback regarding
their experiences. Hearing aids and remote microphone will be returned to the study site
following completion of the trial.
