It is well established that modern directional microphones in hearing aids provide listeners with an improved speech understanding in noise. De-spite this, the impact of directional microphones in real life conditions is limited. In fact, hearing in noise remains one of the biggest problems for hearing aid users. Fortunately, recent developments in super-directional technology, at least in laboratory settings, promise to deliver significant benefits to hearing aid users. Experiments suggest large improvements in speech understanding in noise and significant preference for highly directional systems. This advantage is often extrapolated to suggest equal advantages in real world listening situations. However, it is increasingly apparent that hearing in noise entails various complex tasks for the listener. Consequently, super-directional technology may be advantageous in some situations but may also have some limitations in its usage. Here we present a discussion of super-directional microphone technology based on several studies. In our research we have examined various factors that influence benefit such as beam width design, adaptation speed, preservation of spatial cues, vent sizes, acoustic scene, and reverberation. Our evidence appears to be confounded by individual characteristics of the listener such as age, hearing loss, personality traits, and cognition. All these factors combined will guide our discussions and thoughts about future research and development of super-directional systems.
Available at: http://works.bepress.com/earl-johnson/71/