The Production of Question Intonation by Young Adult Cochlear Implant Users: Does Age at Implantation Matter?

Abstract

Purpose The purpose of this observational study was to investigate the properties of sentence-final prosody in yes/no questions produced by cochlear implant (CI) users in order to determine whether and how the age at CI implantation impacts CI users' production of question intonation later in life. Method We acoustically analyzed recordings from 46 young adult CI users and 10 young adults with normal hearing who read yes/no questions. Of the 46 CI users, 20 had received their CI before the age of 4.0 years (early implantation group), 15 between ages 4.0 and 8.11 years (midimplantation group), and 11 at the age of 9.0 years or later (late implantation group). We assessed the prosodic properties of the produced questions for each implantation group and the normal hearing comparison group (a) by measuring the sentence-final rise in fundamental frequency, (b) by labeling the question-final intonation contour using the Tones and Breaks Index ( Beckman & Ayers, 1994 ; Silverman, Beckman, et al., 1992 ; Veilleux, Shattuck-Hufnagel, & Brugos, 2006 ), and (c) by assessing phrase-final lengthening. Results The fundamental frequency rises produced by all CI users exhibited a smaller magnitude than those produced by the normal hearing comparison group, although the difference between early implanted CI users and the normal hearing group did not reach statistical significance. Early implanted CI users were more comparable in their use of question-final intonation contours to the individuals with typical hearing than to those users with CI implanted later in life. All CI users exhibited significantly less phrase-final lengthening than the normal hearing comparison group, regardless of age at CI implantation. Conclusion The results of this investigation of question intonation produced by CI users suggest that those CI users who were implanted with CI earlier in life produce yes/no question intonation in a manner that is more similar to, albeit not the same as, individuals with normal hearing when compared to the productions of those users with CI implanted after 4.0 years of age.