Babbling Complexity Speech Outcomes in Children With Cochlear Implants

Babbling Complexity and Speech Outcomes in Children with Cochlear Implants Elizabeth Walker, MA Sandie Bass-Ringdahl, PhD The University of Iowa, Iowa City, IA Babbling and early speech in infants with normal hearing   Research indicates continuity between prelinguistic vocalizations and early speech development Stoel-Gammon (1989)  Children who are “poor babblers” (i.e., produce limited babbling with few consonants) may produce first words later and acquire lexical items more slowly than children with more complex babble Babbling and early speech in infants who are deaf or hard of hearing (D/HH)   Few studies on relationship between babbling and early speech and language in this population Wallace, Menn, & Yoshinaga-Itano (1998)    Examined relationship between babbling quality and hearing loss Measured phonetic complexity in babbling for infants between 5 and 13 months Found no significant relationship between babbling and demographic variables (PTA) or outcome variables (articulation measures) Rationale and Research Questions  Clinicians need more informal measures for tracking speech and language progress in children receiving CIs under the age of 2.  Can measures of phonetic complexity in babbling be used to track progress for infants with CIs?  Finding a predictive relationship between babbling complexity and speech/language outcomes provides us with a means for assessing progress in very young children with CIs.  Does babbling complexity predict speech and language outcomes in this population? Method  Participants    19 infants with prelingual SNHL Mean age at first visit, 13.74 months (4-27 months) Mean age at initial stim, 18.39 months (11-27 months)  Data collection    Vocal recordings collected at pre- and post-CI visits Infant interacted with experimenter and caregiver Sessions followed similar protocol across participants Method: Mean Babbling Level (MBL)    Measured phonetic complexity of babbling using Mean Babbling Level (MBL) analysis (Stoel-Gammon, 1989) Transcribed maximum of 50 vocalizations per visit Vocalizations isolated based on 2-second breath groups  Vocalizations with greater than 2 second pause separating them were considered to be two different vocalizations Method: Mean Babbling Level (MBL)  Vocalizations assigned to levels based on phonetic content and syllable structure     Level I: vowel, syllabic consonant or consonant-vowel combination; consonant is glide or glottal Level II: CV combination in which the consonant is a true consonant; place/manner do not change Level III: at least two true consonants that differ by place and/or manner MBL = (Sum of # of Level I) x 1 + (Sum of # of Level II) x 2 + (Sum of # of Level III) x 3/Total # utterances   Scores range from 1.0 to 3.0 MBL increases with chronological age and is negatively correlated with age at onset of meaningful speech Method: Outcome measures  Language measures collected at approximately 48 months chronological age (mean CA: 49 months; range 39-56 months)     Mean length of CI use: 29 months (18-36 months) Minnesota Communication Development Inventory (MCDI) expressive and receptive language quotient (LQ) scores Goldman-Fristoe Test of Articulation-II standard scores (GFTA-II SS) Peabody Picture Vocabulary Test-III standard scores (PPVT-III SS) Method: Data analyses    MBL scores for participants with multiple data points within time periods averaged at 5 intervals  Pre-implant and initial stimulation  2 week, 1 and 2 months post-CI  3, 4, 5 months post-CI  6, 7, 8, 9 months post-CI  10, 11, 12, 13 months post-CI Pearson Product-Moment correlations calculated for average MBL at 5 time intervals and MCDI Expressive and Receptive LQ, GFTA-II SS, PPVT-III SS Stepwise multiple regression analyses run for average MBL at 6-9 and 10-13 month time intervals and four outcome measures Results: Correlational analyses  Significant correlations between MBL at 6-9 months post-CI and PPVT SS, GFTA SS, and MCDI receptive and expressive LQs     MBL & PPVT: r=.70 (n=17, p<.01) MBL & GFTA: r=.52 (n=18, p<.05) MBL & MCDI Receptive: r=.75 (n=18, p<.01) MBL & MCDI Expressive: r=.75 (n=18, p<.01) Results: Correlational analyses Correlation between PPVT and MBL at 6-9 mos 120 r=.70, p<.01 100 PPVT SS 80 60 40 20 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 MBL at 6-9 mos post CI Results: Correlational analyses  Significant correlations between MBL at 1013 months post-CI and PPVT SS and MCDI receptive and expressive LQs     MBL & PPVT: r=.59 (n=16, p<.05) MBL & GFTA: r=.43 (n=18, n.s.) MBL & MCDI Receptive: r= .63 (n=17, p<.01) MBL & MCDI Expressive: r=.52 (n=17, p<.05) Results: Correlational analyses Correlation between PPVT and MBL at 10-13 mos 120 100 r=.59, p<.05 PPVT SS 80 60 40 20 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 MBL at 10-13 mos post-CI Results: Regression analyses  MBL and MCDI Expressive LQ  67% of the variance accounted for by MBL at 6-9 months post-CI (n=15; p=.0002) 66% of the variance accounted for by MBL at 6-9 months post-CI (n=15; p=.0003) 31% of the variance accounted for by MBL at 6-9 months post-CI (n=15, p=.03)  MBL and MCDI Receptive LQ   MBL and GFTA-II SS   MBL and PPVT-III SS  59% of the variance accounted for by MBL at 6-9 months post-CI (n=15; p=.0009) Discussion  Is mean babbling level an effective measure for tracking progress in very young children with CIs?  MBL is simple to perform and provides clinicians with a gradient measure by which to monitor vocal development in children with CIs.  Is there a significant relationship between babbling complexity and speech and language measures in children with cochlear implants?  Phonetic complexity in babbling predicts later speech and language outcomes in children with CIs, after they have had at least 6 months of listening experience. Take-home message  Clinical implications   Prelinguistic vocalizations may be an important prognostic indicator for later speech and language development Low MBL scores after 6 months of CI use may indicate a need to increase clinical services or change CI MAP Babbling is continuous with speech and language in children with hearing loss Once children are exposed to auditory input, they will show a progression in vocal development that is similar to younger, normal-hearing peers  Theoretical implications   Acknowledgements  Funding support  NIH/NIDCD Grant P50 DC00242; Grant RR00059 from the General Clinical Research Centers Program, NCRR, National Institutes of Health; the Lions Clubs International Foundation; and the Iowa Lions Foundation  University of Iowa Pediatric Cochlear Implant team  J. Bruce Tomblin, Brittan Barker, Linda Spencer, Maura Kenworthy, and Tanya Van Voorst Michele Arata, Erin Becker, Kate Larsen, Greta Martin, and Katie Woodard  University of Iowa Pediatric Audiology lab 