Acquisition of prosodic prominence in children implanted with cochlear prostheses in early infancy Olga Gordeeva Speech and Hearing Sciences Queen Margaret University College Research workshop 01/02/206

This presentation  Cochlear implantation of infants and its influence on the later speech production and perception  MC intra-european research fellowship (submitted) CI Situation in Flanders CI Situation in Flanders Aims of this project Aims of this project

Cochlear implants  Bypass malfunctioning (or missing) outer hair cells in the inner ear  Direct stimulation of the auditory nerve  Based on digital encoding of speech  Multichannel implants (e.g. Nucleus 24™®) mimic the frequency resolving power of the cochlear

Implantation of infants  CI of infants in Belgium (  Early detection  Neonatal hearing screening programmes use OAE since (1995) 1998  Typically unilateral CI at age 12 – 18 months (as early as possible)  Bilateral implantation is a common practice (but not paid back by health authorities)

Speech production/perception abilities in CI children implanted in infancy  “the earlier the better” CAP or IT-MAIS tests (Schauwers et al. 2004; McConkey Robbins et al. 2004, ;Waltzman & Roland, 2005) indicate rapid improvement in auditory skills during the first year of device use regardless of age at implantation although younger children achieve higher scores. Trigger effect for normal babbling about a month after the switch  Much higher integration chances in mainstream education CI-infants 90% chance of integration in mainstream education (30% at age 4;0) (Govaerts et al. 2003) CI-infants 90% chance of integration in mainstream education (30% at age 4;0) (Govaerts et al. 2003)  Positive effects on the post-implant speech and language development (Schauwers et al 2004 for overview) Auditory perceptual skills/ speech monitoring Auditory perceptual skills/ speech monitoring standardised language measures standardised language measures Speech production within normal ranges (Adi-Bensaid & Bat-el, 2004; Schauwers et al. 2004b) Speech production within normal ranges (Adi-Bensaid & Bat-el, 2004; Schauwers et al. 2004b)  Different in fine phonetic detail compared to normally hearing children Prosodic word age and path are within normal ranges (Adi-Bensaid & Bat-el, 2004), except for atypical for Hebrew long vowels and Prosodic word age and path are within normal ranges (Adi-Bensaid & Bat-el, 2004), except for atypical for Hebrew long vowels and Intersyllabic co-occurrence patterns in babbling (Schauwers et al 2004) Intersyllabic co-occurrence patterns in babbling (Schauwers et al 2004)

This study  Contributes to the question on the influence of the auditory system (with of without hearing- impairment) on speech production (Perkell et al. 1992; Lane et al 1998)  The role of hearing onset in speech and language development  Area relative prosodic prominence in Dutch word-stress and the influence of hearing status (normal, CI, HI) its production/perception  Acoustic signal plays an important mediating role between hearing and speech

Variables  The suprasegmental acoustic correlates of Dutch word- stress (Van Katwijk, 1974; Sluijter 1995; Sluijter et al 1996; Sluijter et al 1997) (Van Katwijk, 1974; Sluijter 1995; Sluijter et al 1996; Sluijter et al 1997)  The acoustic manifestation of Dutch stress differs depending on whether a word carries a phrasal accent or not  Word-stress under phrasal accent is primarily cued by F0 (Hz) (Van Katwijk, 1974; Sluijter 1995; Sluijter 1996) E.g. Ik heb CANON gezien. E.g. Ik heb CANON gezien.  Word-stress without phrasal accent is primarily cued by duration (ms) and spectral tilt (dB, SPL) E.g. Ik heb canon GEZIEN. E.g. Ik heb canon GEZIEN.

Research Questions:  (1) Implanted in infancy CI-children produce the acoustic cues to word-stress and accent to the extent similar to normally-hearing (NH) peers;  (2) The hierarchy (order of importance) of the cues in production is the same in the two groups;  (3) The CI-children perceive the primary acoustic cues to word- stress and phrasal accent to the extent similar to NH peers;  (4) The hierarchy of the primary cues in perception is the same in the two groups;  (5) Any differences between the two groups in production – (1) and (2) – can be explained by the characteristics of those in hearing- impaired (HI) children.  (6) Any differences between the two groups in perception – (3) and (4) – can be explained characteristics of those in hearing-impaired children.

Subjects  Dutch-speaking children age 6;0  attending primary schools in Flanders (Belgium).  NH (N=30), CI children (N=30) and HI children assisted by hearing aids (N=10).  The CI subjects are implanted bilaterally in the first two years of life with the Nucleus 24® devices from Cochlear Ltd.  The CI-subjects are matched to the NH controls by the chronological and hearing age and dialectal background.  The HI-subjects are matched to the CI-children by their pure tone audiometry (PTA) levels.

Experiment (1) Production of word- stress  Aim: investigates the influence of hearing age and status on the relative strength of the acoustic correlates of stress in speech production  In quantitative and more categorical terms  The hypothesis for the NH children follows the adult data for Dutch (Sluijter & van Heuven, 1996b; Sluijter & van Heuven, 1996a).  For the HI controls, it is expected that the importance of F0 as a primary cue to stress under phrasal accent and that of duration as a cue to word-stress should decrease either quantitatively or categorically (O'Halpin, 2001).  For the CI-children, we expect no differences in the hierarchy of cues, but expect to find quantitative differences. (1) influenced by their hearing age and status (based on findings in other speech domains in Adi-Bensaid & Bat-El, 2004; Schauwers et al., 2004b).  Data analysis is based on the semi-automatic procedure developed in (Gordeeva et al., 2003; Gordeeva, 2005)

Materials and Elicitation Elicitation technique Dutch adaptation of subsets from “Profiling Elements of Prosodic Systems - Children” (Peppé & McCann, 2003)

Experiment (2) perception of word- stress  Aim: investigates the influence of hearing age and status on the relative strength of the acoustic correlates of stress in speech perception  Test quantitative and categorical differences between the groups: (1) Condition (the extent), each of the parameters is varied one at a time, while the other parameters are kept equal between the [±stress] syllables. The extent will reflect the success rate of the identification of the stress location for each cue. (2) Condition (establishing the cue hierarchy), competing cues are weighted against each other between the first and the second syllables (following Beckman, 1986). The hierarchy will reflect the order of the winning cues in the identification of the stressed syllables  Pilot test determines the sufficient parameter changes for adult listeners.

Implications  the role of audition in refining speech production dual-process theory of the role of auditory feedback in the production of speech (Perkell et al., 1997) in order to achieve suprasegmental goals that are also a compromise between intelligibility and economy of effort the speaker’s hearing ensures their intelligibility with minimal expenditure of effort  Biotechnology, Audiology, Speech and Language Therapy What correlates are produced/perceived differently What correlates are produced/perceived differently Is the coding tuning of the multichannel CI sufficient Is the coding tuning of the multichannel CI sufficient  Data on the Acoustic Correlates of Word-Stress for Dutch-speaking children