The role of early and late reflections on spatial release from masking

Abstract

It is well documented that older listeners have more difficulty understanding speech in complex listening environments than do younger listeners. Early reflections (occurring <50 ms following the direct sound) have been linked to improved speech intelligibility (Lochner and Burger, 1964), while later-arriving reverberant sound has been shown to limit speech understanding (Knudsen, 1929). However, we do not know how spatial release from masking (SRM) is affected by early and late reflections or how age and hearing loss interacts with the relative influences of each. SRM in two simulated reverberant environments was measured for listeners varying in age and hearing thresholds under three different signal processing conditions: (1) early reflections alone, (2) late reflections alone, and (3) all reflections. Results indicated that though all listeners performed better when only early reflections were present, the older hearing-impaired listeners benefited the most from the absence of late reflections. Effects of age and hearing loss on performance and SRM under these three different signal processing conditions will be discussed. [Work supported by NIH R01 DC011828.]