A wide dynamic range speech test for the evaluation of compression hearing aids
Arlene C. Neuman, Matthew H. Bakke, Harry N. Levitt · The Journal of the Acoustical Society of America · 1989
Wide dynamic range test materials have been developed for the evaluation of compression hearing aids. Anomalous sentences containing four monosyllabic test words per sentence were recorded by a female talker. The four test words in each sentence were then scaled (using a waveform editing system) to represent four different sound-pressure levels covering a 30-dB range (in 10-dB steps). Performance on this speech material was compared to a performance-intensity function obtained using monosyllabic word lists at the same four sound-pressure levels. Testing was done for a linear and two compression systems (compression ratio of 2.5, instantaneous attack time, release times of 20 and 140 ms). For all three conditions, frequency shaping based on a half-gain rule was used. Ten listeners with sensorineural hearing loss served as subjects. Results of the experiment indicated that the wide dynamic range test material was sensitive to the dynamics of the compression system being evaluated, while the monosyllabic word materials presented at discrete levels was not. [Work supported by NIH Grant No. PO1 NS17764.]