Directional hearing matters

FAQs - Directional hearing

• Q1 - Why is Signia directionality beneficial to your customers?

  Signia offers the ideal solution to all listening situations. While emphasis is always placed on ensuring that target speech is effortlessly audible, an intelligent steering component ensures that other important aspects of hearing, such as sound quality and spatial awareness, are taken into account at all times. For example, it is well established that the narrower the directional focus of the microphones, the more spatial cues are compromised. Therefore, the SpeechMaster technology fades among TruEar (a microphone response for BTE and RIC instruments designed to mimic the natural directivity of the outer ear), standard directional, and Narrow Directionality. This fading occurs as is necessary to balance the shifting wearer listening priorities between spatial awareness and speech intelligibility.

  In quieter environments where speech is easily understood, TruEar mode ensures that localisation cues are preserved. As more noise is introduced and speech intelligibility is increasingly compromised, standard directional microphones can improve the signal-to-noise ratio (SNR) for the wearer while still maintaining significant spatial cues. At the other end of the spectrum, in very noisy situations, people naturally converse in significantly smaller groups huddled close together, in which case all conversation partners are within the wearer’s visual range. In such situations, speech understanding is a decisive listening priority over localisation, and SpeechMaster fades in Narrow Directionality.

  As reported by Picou and colleagues (2014), when visual cues are present, localisation is maintained even with narrow beamforming. In fact, since signals are processed differently for the left and right hearing aids in the generation of Narrow Directionality, the spatial information of the non-target sound sources is actually maintained. In this way, the user obtains unparalleled benefit of the enhanced SNR for the target speaker without having to accept an acoustic “tunnel effect.” This automation and intelligent steering system means that the wearer can enjoy the optimum listening experience throughout the day without the need to make any manual adjustments.

• Q2 - When does directionality matter?

  Directionality matters when speech needs to be heard and understood in noisy situations. Imagine trying to hear the public announcement at a busy railway station or trying to talk to your friend in a crowded bar. Even if you can hear and understand, you need to concentrate. In these situations where there’s a high level of distracting ambient sound, directionality can provide significant benefit by reducing the sounds coming from directions other than where the target speech originates.

  Louder environments include ambient sounds like music, noises or other people talking. In such an environment, we usually face our conversation partner directly and may even move closer to them in order to understand them better. primax supports this natural behaviour by applying directionality. The strength of the directionality depends on the overall loudness and complexity of the situation. In these environments, the wearer wants to understand the person in front of them. Directionality supports this by reducing sounds from the sides and from behind.

  In other situations such as when we’re riding in a car, the target speech may not always originate from the front, and the driver cannot always turn to face the speaker. primax Spatial SpeechFocus is the directional feature which can keep the focus on the target speaker, whether it is coming from the front, back, or either side, all the time attenuating noise from the other directions.

• Q3 - How does Narrow Directionality work?

  Signia’s unparalleled Narrow Directionality addresses the infamous “cocktail party situation”. When ambient noise comes from all around the listener and includes other people talking, people with hearing loss encounter more problems than their counterparts with natural hearing. This is because those with normal hearing can rely on auditory processing effects such as binaural squelch and binaural directed listening to help filter out everything else and focus on the speech that they want to listen to. Not only does primax technology outperform all other hearing aids, its wearers are clinically proven to hear even better in very noisy situations than people with natural hearing (see Q6).

  primax activates its Narrow Directionality automatically and only when the listening situation becomes especially noisy and difficult. When the situation warrants it, Narrow Directionality increasingly narrows the beam of the microphone focus so that at its most effective, essentially everything that is not immediately in front of the wearer is reduced.

  Narrow Directionality is seamlessly integrated into and on top of the existing 48 channel standard directional processing and digital noise reduction strategies such as directional speech enhancement. So in noisy situations, the standard directional microphone system would be active as usual, but when the listening
  conditions become even more difficult, Narrow Directionality would smoothly and automatically engage and adapt accordingly to ensure a consistent sound impression.

• Q4 - How does primax ensure that wearers do not suffer from a “tunnel effect”?

  The so called “tunnel effect” is only undesirable when the wearer doesn’t need it, such as when the acoustic situation is quieter and the wearer would prefer to hear from all around. In these situations, Narrow Directionality is not engaged, and therefore, there is no “tunnel effect”. On the other hand, in those very noisy situations where Narrow Directionality is engaged, the “tunnel effect” is exactly what the wearer wants in order to hear the speech from the front, and not the noise from anywhere else. The “tunnel effect” is beneficial and desirable in such situations (see Q1).

  In fact, the frequency sensitivity of Narrow Directionality is unique and unprecedented. Keeping Narrow Directionality to as few frequency channels as possible, together with other signal processing strategies, allows the wearer to still retain a sense of the acoustic environment outside of the Narrow Directionality focus beam. In other words, in order to preserve spatial cues as much as possible, Narrow Directionality is activated in only as many channels as necessary for optimal speech understanding in noisy situations.

  This is important because when you hone in on a sound source and block out signals from other directions, there’s the risk that you feel you can no longer hear from the other directions. By activating in only as many channels as the acoustic situation necessitates, Narrow Directionality improves speech intelligibility in difficult listening environments without sacrificing spatial cues.

• Q5 - What is the SpeechMaster solution?

  primax technology capitalises on the latest innovations in audiology to achieve reduced listening effort for a wide variety of speech environments. This is achieved by selectively activating and steering three key technologies in parallel: noise reduction, directionality and by steering amplification to target and elevate the dominant speaker over all other sounds in any environment.

  SpeechMaster orchestrates all features, including directionality, according to environmental changes to highlight the conversation partner’s voice. It delivers outstanding sound quality, making hearing effortless and redefining the ease of listening in all situations, all day long.

• Q6 - Has the superior effectiveness of Signia’s technology been proven?

  Yes. Two independent studies conducted at the University of Northern Colorado and Oldenburg Hörzentrum examined the effectiveness of the new features of primax by collecting and analysing ongoing electroencephalographic (EEG) brain activity data while subjects performed speech intelligibility tests over longer periods than conventional hearing tests.

  For both primax features SpeechMaster and EchoShield, the objective brain behaviour measures revealed a significant reduction in listening effort when the feature was activated. By using Narrow Directionality, speech reception thresholds (SRT) in cocktail-party situations were improved by up to 2.9 dB for wearers with mild to moderate hearing loss compared to people with natural hearing.