The study was carried out to assess the role that five hearing history variables (chronological age, age at onset of deafness, age of first cochlear implant [CI] activation, duration of CI use, and duration of known deafness) play in the ability of CI users to identify speaker gender.
Forty-one juvenile CI users participated in two voice gender identification tasks. In a fixed, single-interval task, subjects listened to a single speech item from one of 20 adult male or 20 adult female speakers and had to identify speaker gender. In an adaptive speech-based voice gender discrimination task with the fundamental frequency difference between the voices as the adaptive parameter, subjects listened to a pair of speech items presented in sequential order, one of which was always spoken by an adult female and the other by an adult male. Subjects had to identify the speech item spoken by the female voice. Correlation and regression analyses between perceptual scores in the two tasks and the hearing history variables were performed.
Subjects fell into three performance groups: (1) those who could distinguish voice gender in both tasks, (2) those who could distinguish voice gender in the adaptive but not the fixed task, and (3) those who could not distinguish voice gender in either task. Gender identification performance for single voices in the fixed task was significantly and negatively related to the duration of deafness before cochlear implantation (shorter deafness yielded better performance), whereas performance in the adaptive task was weakly but significantly related to age at first activation of the CI device, with earlier activations yielding better scores.
The existence of a group of subjects able to perform adaptive discrimination but unable to identify the gender of singly presented voices demonstrates the potential dissociability of the skills required for these two tasks, suggesting that duration of deafness and age of cochlear implantation could have dissociable effects on the development of different skills required by CI users to identify speaker gender.
Cochlear implant users exhibit large individual variations in performance on speech perceptual tasks, and the relationship of this variation to hearing history is not understood in detail. Five historical variables (age at deafness diagnosis, age at implant activation, duration of deafness, duration of implant use, and chronological age at testing) were examined in relation to performance in two voice gender identification tasks by juvenile CI users. The results suggest that deafness duration and age at implant activation may affect dissociable aspects of auditory perceptual development.
1SUVAG Polyclinic, Zagreb, Croatia; 2Cognitive Neuroscience Sector, Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy; and 3Behavioral Neurosciences Program, McGill University, Montreal, Canada.
This work was supported by the Croatian Ministry of Science, Education and Sports Grant (207-0000000-2293), the Central European Initiative Science and Technology Network Research Fellowship (to D. K.), NSERC 298612 and CFI 9908 (to E. B.), and SISSA.
Address for correspondence: Dr. Damir Kovacic, Laboratory of Auditory Neurophysiology, Department of Neurosciences, Katholieke Universiteit Leuven, Herestraat 49, bus 1021, B-3000 Leuven, Belgium. E-mail: email@example.com.
Received June 12, 2009; accepted June 19, 2010.