Summary:
A new study shows that Signia’s Binaural OneMic Directionality 2.0 (BOMD 2.0) technology can significantly improve speech understanding in noise for wearers of single-microphone hearing aids.
Key Takeaways:
- BOMD 2.0 uses advanced binaural processing and ear-to-ear communication to create a virtual directional system, overcoming the traditional limitations of single-microphone CIC devices.
- In testing, BOMD 2.0 provided a statistically and clinically significant improvement in speech reception thresholds, enhancing real-world communication in noisy environments.
- The technology allows hearing care professionals to offer patients both the discretion of near-invisible hearing aids and the performance benefits of directional processing.
Tech Topic
By Niels Søgaard Jensen, MSc; Barinder Samra, MSc; Jens Hain, MSc; Eric Branda, AuD, PhD; Jennifer Weber, AuD
Single-microphone hearing aids with directionality provide a unique combination of discretion and performance in noise. In this article, we present and discuss the results from a study showing significant benefits provided by the Signia Binaural OneMic Directionality 2.0 technology. The results demonstrate how this technology can help hearing care professionals and hearing aid wearers who look for solutions delivering improved speech-in-noise performance without compromising on the discretion of small, near-invisible hearing aids.
Introduction
In challenging listening environments, such as dynamic social gatherings or noisy public spaces, understanding speech can be difficult for individuals with hearing loss.1 Directional microphone technology has long been recognized as a key method to improving speech understanding in noise by enhancing sounds from the direction of the speaker while suppressing background noise.2
Dual-microphone hearing aids achieve directional benefits through beamforming techniques that utilize the physical distance between the two microphones. However, this type of traditional directionality has not been feasible in smaller hearing aids, such as completely-in-canal (CIC) models, as their ultra-compact design allows space for only a single microphone.
Signia’s Binaural OneMic Directionality (BOMD) technology is designed to overcome inherent constraints by leveraging advanced binaural processing to enable a virtual directional microphone system from two single-microphone hearing aids.
With the introduction of the Signia Integrated Xperience (IX) platform, an updated version, Binaural OneMic Directionality 2.0, was released. BOMD 2.0 technology is available in all Signia IX single-microphone form factors—Silk Charge&Go IX, Insio IIC/CIC IX, and Insio Charge&Go CIC IX—offering the same performance and wearer benefits for all form factors. Therefore, this article will focus on the BOMD 2.0 technology across the different form factors.
Binaural OneMic Directionality 2.0
A key element in BOMD 2.0 is Signia’s proprietary low-latency, wide-bandwidth ear-to-ear communication system, e2e 4.0. This binaural link enables instantaneous synchronization and audio transmission between the two hearing aids.
Each hearing aid captures sound via its microphone, and by sharing and synchronizing acoustic information between the left and the right hearing aids in real time, the system functions as a virtual directional two-microphone array, which offers beamforming in both hearing aids, as illustrated in Figure 1.
Advanced signal processing algorithms analyze interaural differences in sound level, time, and phase cues to distinguish target speech from background noise. Using these spatial cues, adaptive binaural beamforming is applied to enhance the desired speech signal from the front while suppressing unwanted sounds from other directions. This beamforming effect is combined with the natural directional effect of the pinna, which is largely preserved by the microphone position in the ear canal.
Based on a range of indicators, the system monitors the surroundings and adapts to changes by smoothly transitioning between binaural beamforming and omnidirectional processing, depending on the listening needs in each situation.
Unlike conventional single-microphone hearing aids, which only provide an omnidirectional response without directional enhancement, BOMD 2.0 enables Signia IX single-microphone hearing aids to offer a substantial improvement in the signal-to-noise ratio (SNR) for signals coming from the front, such as in a face-to-face conversation in background noise.
This improvement has been demonstrated in technical measurements where the directional performance of a Signia Insio Charge&Go CIC IX hearing aid with BOMD 2.0 was compared to the performance of single-microphone CIC hearing aids with traditional omni-directional processing, and where an SNR improvement of more than 7 dB was observed.3 Increasing the SNR by 7 dB corresponds to increasing the intensity ratio between speech and noise by a factor of five.
The study presented in this article assessed the positive impact of the directional benefit of BOMD 2.0 on speech understanding.
Study: Speech Understanding in Noise
We conducted a study at the University of Northern Colorado, USA, with the aim of testing the effects of BOMD 2.0 on speech understanding in noise.
Methods
The study included 17 participants. Their average age was 69 years (SD: 13 years, range: 25-80 years), and they included 10 females and 7 males. All participants had a sensorineural hearing loss, with an average four-frequency pure tone average (PTA) hearing loss of 44 dB HL (SD: 10 dB HL, range: 22-62 dB HL).
The participants were fitted binaurally with Signia Silk Charge&Go IX hearing aids with BOMD 2.0 technology. The hearing aids were programmed individually using the NAL-NL2 rationale. Power sleeves were used for all fittings. The hearing aids were programmed with two different test programs, one with BOMD 2.0 activated and another with BOMD 2.0 deactivated, ie, offering traditional omnidirectional processing (referred to as “OMNI”). The gain and all other feature settings in the two programs were identical.
To test the participants’ ability to understand speech in noise with each of the two programs, a modified version of the American English Matrix test4 was conducted. The test was run in a sound-treated room. Target sentences were presented from a loudspeaker in front of the participant, while babble noise was presented from four other loudspeakers (at 45°, 135°, 225° and 315° azimuth) at a level of 67 dBA. The task of the participant was to repeat each sentence, and the level of the speech was changed adaptively after each sentence, targeting the SNR where 80% of words could be repeated correctly. This specific SNR is the outcome of the test and will be referred to as the Speech Reception Threshold for 80% speech understanding (SRT80).
The order of the two hearing aid programs was counterbalanced across the participants. More details on the methodology are available in a white paper.3
Results
The mean SRT80 across the participants for the two test conditions, OMNI and BOMD 2.0, are shown in the bar graph in Figure 2.
The graph in Figure 2 indicates a clear difference between the two programs. For OMNI, the mean SRT80 was 0.2 dB, while it was -1.1 dB for BOMD 2.0. Accordingly, since a lower SRT80 score indicates better performance, BOMD 2.0 provided a mean benefit of 1.3 dB. This difference was statistically significant according to a paired t-test (t(16) = 2.47, p < .05). Thus, as expected, the activation of BOMD 2.0 resulted in a significant improvement in speech understanding in the complex listening scenario included in the test.
Discussion
The study reported in this article showed a significant improvement in speech understanding when BOMD 2.0 was activated, thereby confirming that the SNR benefit observed in a technical study7 translates directly into a human performance benefit. The observed speech understanding improvement of 1.3 dB is both statistically and clinically significant. It may be the difference between being able to follow a conversation and having to give up in a real-world listening situation where a hearing aid wearer would struggle to understand speech using conventional omnidirectional processing.
For HCPs, the ability to provide small single-microphone hearing aids with the directionality offered by Signia’s BOMD 2.0 technology means they can offer a unique solution for hearing aid wearers who need support in challenging communication situations in noise but do not wish to compromise on the discretion provided by CIC hearing aids. In fact, it could be argued that the speech enhancement in noise delivered by BOMD 2.0—as demonstrated in the study—adds to the discretion of the small hearing aids by drawing less attention to the hearing loss of the wearer.
Niels Søgaard Jensen, MSc, is senior evidence and research manager at Signia, Lynge, Denmark (corresponding author: [email protected]). Barinder Samra, MSc, is commercial audiology manager at Signia, Lynge, Denmark. Jens Hain, MSc, is lead engineer, signal processing at Signia, Erlangen, Germany. Eric Branda, AuD, PhD, is director, hearing technology & research at Signia, USA. Jennifer Weber, AuD, is professor emerita in the Department of Communication Sciences & Disorders at the University of Northern Colorado.
References
1. Picou EM. Hearing aid benefit and satisfaction results from the MarkeTrak 2022 survey: Importance of features and hearing care professionals. Seminars in Hearing. 2022;43(4):301-316. doi:10.1055/s-0042-1758375
2. Bentler RA. Effectiveness of directional microphones and noise reduction schemes in hearing aids: A systematic review of the evidence. Journal of the American Academy of Audiology. 2005;16(7):473-484. doi:10.3766/jaaa.16.7.7
3. Jensen NS, Samra B, Hain J, Branda E. Binaural OneMic Directionality 2.0 delivers 5 times the speech enhancement in noise versus key competitors. Signia White Paper. 2025. Retrieved from www.signia-library.com.
4. Hörtech. International Matrix Tests: Reliable speech audiometry in noise. 2019. Report from HörTech gGmbH. Retrieved from www.hz-ol-de
