Abstract
The study of the phonoprosodic structure of spontaneous speech of infants wearing cochlear implants, comprises a fresh attempt for recording and analysing premature speech for diagnostic and interventional purposes. This study of prelinguistic speech both for typically developing infants as well as those with cochlear implants, does not consist of an easy task, since the traditional linguistic tools of analysis based on adult language cannot be used readily for the accurate description of adult speech. Therefore, the present Thesis proceeds to the analysis of infant speech through acoustical and auditory analysis, based on the principles of infraphonological model of Oller (2000). The innovation of the Thesis lies in the analysis of infant speech of protophones of typically developing and also of infants wearing cochlear implants, contributing both to international and to the substantially lacking Greek bibliography.It is acknowledged nowadays that prosodic fluctuations consist of the ...
The study of the phonoprosodic structure of spontaneous speech of infants wearing cochlear implants, comprises a fresh attempt for recording and analysing premature speech for diagnostic and interventional purposes. This study of prelinguistic speech both for typically developing infants as well as those with cochlear implants, does not consist of an easy task, since the traditional linguistic tools of analysis based on adult language cannot be used readily for the accurate description of adult speech. Therefore, the present Thesis proceeds to the analysis of infant speech through acoustical and auditory analysis, based on the principles of infraphonological model of Oller (2000). The innovation of the Thesis lies in the analysis of infant speech of protophones of typically developing and also of infants wearing cochlear implants, contributing both to international and to the substantially lacking Greek bibliography.It is acknowledged nowadays that prosodic fluctuations consist of the basic communication characteristic of the infant, either during perception or production of speech. Consequently, for the purposes of the present Thesis, it was considered necessary to conduct an analysis of prosodic features of protophones, which dominate during infantile speech. Thisanalysiswasperformedthroughthe protophone prosodic characteristics of duration and pitch. Morespecifically, the particular objectives of the Thesis were a) to record the structures of canonical babbling in infants and children of very young age with cochlear implants in respect with the syllabic sequence of consonants and vowels, b) to analyse the range of prosodic fluctuations of protophones mainly of canonical babbling, c) to analyse their duration, d) to compare all the above features with a control group of typically developing infants in order to determine whether the trajectory of the protophone development in children with cochlear implants follows a normal or deviant, peculiar course and finally, e) to present a comparison between infants implanted before or after the 24 months of chronological age since older researches indicated that more benefits emerged from cochlear implantation to the first group rather than the second one.Overall, three typically development infants (TD) participated, aged 0:8-1:1 and seven infants wearing cochlear implants, with chronological age at the beginning of recordings 1:10-4:0 years and post implantation age from the beginning until completion of the study 0:0-1:3 years. The children were selected as candidates to receive a cochlear implant under the criteria of the ENT clinic protocol of the AHEPA University Hospital in Thessaloniki. They were not diagnosed with any other developmental disorder apart from deafness, pre-operatively, the children had PTA 95-110 dB ΗL and were not benefited from the use of simple acoustic devices. The recordings of spontaneous productions were performed through appropriate equipment in a familiar environment (home), at frequent periods of time through interaction with caregivers. The post implantation age of infants with cochlear implants were matched with the hearing age of typically developing infants, covering eventually the first year. Following data collection, acoustical analysis was performed through appropriate speech analysis software (Praat). Thus, both the duration and pitch differences of protophones were measured. Furthermore, the number of protophones was classified based on the number of syllables of each protophone type via wide band spectrography aiming at the identification of the most frequent use of protophone syllabic structure in the Greek language. For the completion and diffusion of the research results, all the rules of anonymity and consent forms of the participants were followed and gathered.Concerning the results, very satisfactory rates of agreement among the raters were initially noted. The findings of the present Thesis indicated a) a tendency of infants with cochlear implants to produce isolated vowels of longer duration compared to typically developing peers. This fact was regarded as a weakness for infants with implants, since shorter duration comprises a sample of greater maturity of the speaker. In addition, b) the disyllable structure CVCV was found to be the most frequent protophone type of speech over the first year post-operatively, whether the infants received the implant before, or after 24 months of chronological age. This conclusion is in line with the outcomes for the Greek language, however, through typical development. Also, c) the appearance of the monosyllable structure of CV recorded since the beginning of the first stages of prelinguistic speech in children with cochlear implants. d) There was no significant statistical difference between the mean pitch difference of typically developing infants and the CI1 infants (group with earlier implantation). This assumption suggests that when cochlear implantation is performed to children younger than 2 years old, it may be compared with the performance of children with normal hearing. The respective mean pitch difference of the CI2 group was also found to be not significantly different from that of typically developing infants. This result suggests that these infants are destined to adopt linguistic behaviours based on the characteristics of the dominate language, while maturity-related factors should be taken into consideration (chronological age at the beginning of recordings 2:1-4:0 years).In contrast to previous studies based on typical development which argued for the existence of only one syllable type at each stage of prelinguistic speech, the present Thesis e) recorded simultaneous co-existence of multi-syllable types of protophones. This finding relates to the second half of the first year of development of typically developing infants and to the first post-operative year of infants with CIs.Quantitative classification of protophones with the parallel evaluation of their suprasegmental features, through the combination of acoustic and auditory analyses provides a new reliable perspective for comparisons between populations with similar hearing experience. These comparisons of high diagnostic value are able to equip us with new linguistic information about disordered speech. With their turn these information can positively contribute to the formation and design of new evaluation and intervention techniques useful to speech pathology (which have not been developed yet for the Greek language) and audiology.
show more
