Maximizing Speech Understanding and Listening Comfort in Noise by Mark C. Flynn, PhD A discussion on selecting the best fitting rationale for a patient, and the use of directional microphone and DSP technology for comfort and hearing in noise. The interference of background noise is the single greatest problem reported by hearing aid wearers. 1 It is crucial that the effects of listening in background noise be taken into account not only when designing new hearing aids but also when dispensing modern hearing aids. Premium digital hearing aids should maximize speech intelligibility while providing excellent comfort in noise. This is not a new concept and has been the foundation of some of our hearing instruments and fitting rationales for years. This article addresses three questions that are crucial to providing optimal speech understanding in noise, along with ensuring listening comfort: 1. What are the features of a prescriptive rationale that will affect speech understanding? 2. How do people with a hearing loss best perceive and understand speech in noise? 3. How can we make listening more comfortable and natural when speech is not present? Hence, speech should be our top priority and is where we should start in answering the questions raised. Selecting the Best Rationale While there are a number of different technologies (eg, directional microphones, speech enhancement algorithms, noise reduction strategies, etc) designed to maximize speech understanding in noise, the effect of the overall speech processing rationale that the hearing instrument utilizes needs to be understood. Recently, Schum & Pogash 2 examined three different levels of technology which broadly represent the market today. Those being linear, Wide Dynamic Range Compression (WDRC), and a premium digital product (in this case, Adapto by Oticon). They reported statistically significant differences between all three levels of technology (Figure 1) in terms of speech understanding in quiet and in background noise. These results demonstrated that speech understanding, especially in challenging listening situations, can be improved first by the use of multi-channel, non-linear amplification and further by the advanced signal processing capabilities of modern digital hearing aids. Figure 1. Mean word recognition (50-word lists of W22) in quiet, moderate (60 dB HL, + 10 SNR) and high (70 dB HL, + 5 dB SNR) noise for three groups of technology: Linear, Wideband Dynamic Range Compression (WDRC) and Advanced Digital. Reprinted with permission from Schum & Pogash.2 The advantages of non-linear signal processing over linear hearing instruments are fairly clear, but it is not so obvious why a premium product should provide significantly better speech perception in quiet and noise than a WDRC instrument in the absence of directional microphones. While Adapto does implement