Remote Microphone Candidacy Study
Condition: Hearing Loss, Sensorineural
MeSH terms: Hearing Loss; Hearing Loss, Sensorineural
Study type: Interventional

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
    

Detailed 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.
    

Intervention name(s): Remote Microphone
Intervention type(s): Device
Intervention description(s): Experienced hearing aid users will be trained on and use a remote microphone for 30 days. Pre- and Post- measures will be taken to determine benefit. Participant characteristics will also be assessed (such as self-efficacy) to explore personality factors that may contribute to benefit from devices.
Other intervention name(s): Roger Select
Intervention model: Single Group Assignment
Intervention model description: Within-subject design: Baseline assessments compared to post-trial results.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Assistive Listening Device (ALD); Hearing in Noise