Providing excellent speech intelligibility in noise continues to be a challenge for hearing instrument manufacturers. Directional technology has come a long way from omnidirectional processing to Binaural Directionality that uses automatic microphone steering strategies to facilitate true binaural processing in the brain.
Resound’s Erica Koehler, AuD and Snehal Kulkarni, AuD delivered a presentation at this year’s AudiologyNOW! convention reviewing the evolution of directional microphone technology and its limitations as well as introducing the benefits of a Binaural Processing Strategy to support a more natural, binaural processing, promoting audibility, and intelligibility.
In the natural world, most people listen by turning toward the person or sound they want to hear and away from the background noise. The two ears, binaural hearing, send distinct information to the auditory cortex of the brain to create a complete, rich and accurate portrayal of the auditory environment and the individual decides what to focus on and what to ignore.
Conventional directional processing aims to reduce sounds from the rear or sides and assumes the signal of interest is in the “look direction.” Today’s most common technology is the two mic system which attenuates sounds by sampling inputs at the front and rear mics. Directional systems present the following limitations which take away from the natural sound picture:
- Listener’s intent is ignored.
- Bilateral hearing, not binaural. With bilateral hearing the focus is on the hearing instrument not the natural sound environment.
- Low frequency roll off inherent in d-mics.
- Offers only omni and fixed directional options.
- Relies on button pushing (30% of individuals do not switch programs).
- Auto switching is not perfect.
By moving to a Binaural Processing Strategy, where the focus is on the user and the natural sound delivery process to the brain not on the hearing instrument, the ReSound Verso is able to give back to the individual binaural directionality and a more holistic and natural sound picture. Individuals regain the ability to choose what to listen to instead of having the instrument make the decision for them as well as overcome the other limitations of a conventional directional system.