The effects of unfiltered and bimodal filtered stimulus conditions on speech discrimination in noise through simulated television audio circuitry

A comparison was made of speech intelligibility scores for CID Everyday Sentences presented in +10dB signal-to-noise ratio in two listening conditions. Ten subjects with mild-to-moderate high frequency sensory hearing impairments were used. One condition consisted of an unfiltered presentation through simulated television audio circuitry. The second condition presented the stimuli bimodally through simulated television audio circuitry employing a 1000 Hz low band pass filter and a 4000 Hz high band pass filter, with slopes of 18 dB per octave toward the outer frequencies and 65 dB per octave toward the center frequencies.

Analysis of the data revealed a significant difference at the .05 level, indicating intelligibility scores to be better in the un-filtered condition. Also, the intelligibility scores of the hearing-impaired subjects deteriorated considerably in noise when compared to scores obtained in quiet.