Directional benefit in simulated classroom environments

PURPOSE: To examine speech recognition performance and subjective ratings for directional and omnidirectional microphone modes across a variety of simulated classroom environments. METHOD: Speech recognition was measured in a group of 26 children age 10-17 years in up to 8 listening environments. RESULTS: Significant directional benefit was found when the sound source(s) of interest was in front, and directional decrement was measured when the sound source of interest was behind the participants. Of considerable interest is that a directional decrement was observed in the absence of directional benefit when sources of interest were both in front of and behind the participants. In addition, limiting directional processing to the low frequencies eliminated both the directional deficit and the directional advantage. CONCLUSIONS: Although these data support the use of directional hearing aids in some noisy school environments, they also suggest that use of the directional mode should be limited to situations in which all talkers of interest are located in the front hemisphere. These results highlight the importance of appropriate switching between microphone modes in the school-age population.