Clinical Trial of Roger Adaptive Digital Technology

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: