Key points are not available for this paper at this time.
Four hearing aid arrangements (monaural-omnidirectional, monaural-directional, binaural-omnidirectional, binaural-directional) and a number of FM system-personal hearing aid combinations (including direct input, neck loop, and silhouette inductor--monaural and binaural--and environmental microphone on and off) were evaluated in a school classroom on nine children with mild-to-moderate sensorineural hearing losses. Two measures of speech recognition in noise were employed. First, the signal-to-noise ratio (S/N) yielding 50% identification of spondees was determined using a simple up-down adaptive procedure. Second, word recognition scores were obtained for three amplification arrangements at two different S/Ns (+6 and +15 dB). The average FM advantage over a personal hearing aid was equivalent to a 15-dB improvement in S/N. Activation of the hearing aid microphone caused most of the FM advantage to disappear. The benefit offered by the FM system decreased as the environmental S/N increased but remained significant even at +15 dB. Significant improvement also was found with the use of directional as compared to omnidirectional microphones, both in the hearing aids and FM teacher microphone.
David B. Hawkins (Thu,) studied this question.