Phonetic context effects in normal-hearing listeners using acoustic simulations of cochlear implant signal

Abstract

Recent work has indicated that the perception of speech sounds shifts as a function of preceding and following context and that these shifts are due in part to the particular spectral makeup of the context sounds [Holt et al., J. Acoust. Soc. Am. 108, 710–722 (2000)]. Aravamudhan and Lotto [J. Acoust. Soc. Am. 118, 1962–1963 (2005)] studied these context effects in listeners with cochlear implants (CI) and the results demonstrated absent or abnormal context-dependent speech perception. The lack of normal context effects in CI users may have practical implications for situations in which there is substantial coarticulation (e.g., nonlaboratory speech) or talker variability (e.g., switching between multiple speakers). Since the representation of speech in CI listeners differs from NH listeners, the current study was designed to investigate the effects of processing normal signals through a CI processor with NH listeners. In particular, we investigated how the spectral resolution of implant input could limit context-dependent perception even in NH listeners. The results showed that the context effects elicited in NH listeners using CI processed signals were similar to CI listeners. The effects of context were moderated by the processing strategy being simulated as well as some of the parameter settings.