- Published on 10 November 2014
A recent study by researchers in the Netherlands and the USA has found that cochlear implant (CI) users may have an impaired ability to categorize speakers by gender. According to the authors, correct gender categorization may benefit speech understanding in competing talker situations. The researchers, from the University of Groningen and UCLA, explain that “In ‘cocktail party’ listening conditions, normal hearing listeners use the voice characteristics of different talkers to track and listen to a target talker. The ability to identify the gender of a voice may help to sort out various talkers in a multi-talker environment, especially when two talkers are speaking at the same time.”
In their study, the authors examined two anatomically related vocal characteristics used to identify a speaker’s gender: the fundamental frequency (F0), related to vocal pitch, and the vocal tract length (VTL), related to the height of the speaker. Nineteen postlingually deafened CI users were recruited for the study. The normal-hearing control group comprised 19 non-musician participants. Synthesized sound stimuli were presented using specific software, with or without vocoding (an analysis and synthesis system used to reproduce human speech).
Statistical analysis of the study results showed a more variable and abnormal pattern for gender categorization in CI users compared to both the normal-hearing and the normal-hearing vocoded modes of hearing. It was also found that CI users’ gender categorization mainly depends on F0 cues, with nearly no contribution of VTL cues. As a result, CI users may not be able to use VTL to segregate competing talkers, possibly making it more difficult to understand speech in multi-talker environments.
Source: Fuller CD, et al. Gender Categorization Is Abnormal in Cochlear Implant Users. Journal of the Association for Research in Otolaryngology. 2014 Aug 30