Isoresponse temporal masking patterns in sensorineural listeners

Abstract

Pure‐tone maskers (200 ms) were adjusted to intensities that just masked short (20 ms) pure‐tone probe signals at low and at moderate sensation levels. (The probe is constant in both frequency and level during a masked threshold determination.) The delays between maskers and probes were varied to obtain what are called isoresponse temporal masking patterns. Results in normal‐hearing listeners are consistent with classical isointensity temporal masking patterns that were obtained by previous investigators, and with isoresponse temporal masking patterns that have been obtained more recently [L. L. Vogten, J. Acoust. Soc. Am. 63, 1520–1527 (1978)1. Some sensorineural listeners required considerably less masker level for temporal masking (interference) to occur than did normal‐hearing listeners, even when masker and probe were in a frequency region of relatively normal sensitivity. This result was obtained whether comparisons were made with probe signals at the same sound pressure levels or at the same sensation levels that were used for normal‐hearing listeners. Temporal masking in some sensorineural listeners also extended over a greater delay time between masker and probe than for normal‐hearing listeners. These findings have implications for current forward‐masking techniques that obtain estimates of frequency selectivity, they also have implications for speech perception by some sensorineural listeners in difficult listening situations. [Research supported in part by NIH Grants Nos. NS10561 and NS12125.]