Use of a simultaneous sentence perception test to enhance sensitivity to ease of listening

The purpose of the study was to determine if a divided-attention, sentence-recall task was more sensitive to distortion of the speech signal than a conventional focused-attention task. The divided-attention task required listeners to repeat both of two sentences delivered simultaneously to the same ear. The focused-attention task required listeners to repeat a single sentence presented to one ear in quiet or in amplitude-modulated noise (0 dB signal-to-noise ratio). Distortion was introduced by peak clipping. Eighteen listeners with normal hearing were tested under three levels of peak clipping: 0 dB, 11 dB, and 29 dB (re: waveform peak). The effects of clipping were similar, on average, for simultaneous sentences and single sentences in noise. When data were separated by sentence length, however, the effects of clipping were found to be greater for the simultaneous-sentence task, but only for the short sentences (6 words or fewer). The simultaneous-sentence test, in its present form, is not more sensitive to the effects of clipping than is a single-sentence test in noise. Modification of the simultaneous-sentence test to include only short sentences, however, may provide greater test sensitivity than more conventional tests using single sentences in noise.