Single word and sentence intelligibility in children with cochlear implants

Everything, altogether, all at once: Addressing data challenges when measuring speech intelligibility through entropy scores

When investigating unobservable, complex traits, data collection and aggregation processes can introduce distinctive features to the data such as boundedness, measurement error, clustering, outliers, and heteroscedasticity. Failure to collectively address these features can result in statistical challenges that prevent the investigation of hypotheses regarding these traits. This study aimed to demonstrate the efficacy of the Bayesian beta-proportion generalized linear latent and mixed model (beta-proportion GLLAMM) (Rabe-Hesketh et al., Psychometrika, 69(2), 167-90, 2004a, Journal of Econometrics, 128(2), 301-23, 2004c, 2004b; Skrondal and Rabe-Hesketh 2004) in handling data features when exploring research hypotheses concerning speech intelligibility. To achieve this objective, the study reexamined data from transcriptions of spontaneous speech samples initially collected by Boonen et al. (Journal of Child Language, 50(1), 78-103, 2023). The data were aggregated into entropy scores. The research compared the prediction accuracy of the beta-proportion GLLAMM with the normal linear mixed model (LMM) (Holmes et al., 2019) and investigated its capacity to estimate a latent intelligibility from entropy scores. The study also illustrated how hypotheses concerning the impact of speaker-related factors on intelligibility can be explored with the proposed model. The beta-proportion GLLAMM was not free of challenges; its implementation required formulating assumptions about the data-generating process and knowledge of probabilistic programming languages, both central to Bayesian methods. Nevertheless, results indicated the superiority of the model in predicting empirical phenomena over the normal LMM, and its ability to quantify a latent potential intelligibility. Additionally, the proposed model facilitated the exploration of hypotheses concerning speaker-related factors and intelligibility. Ultimately, this research has implications for researchers and data analysts interested in quantitatively measuring intricate, unobservable constructs while accurately predicting the empirical phenomena.

Measuring speech intelligibility with deaf and hard-of-hearing children: A systematic review

There is great variability in the ways in which the speech intelligibility of d/Deaf and hard-of-hearing (DHH) children who use spoken language as part, or all, of their communication system is measured. This systematic review examined the measures and methods that have been used when examining the speech intelligibility of children who are DHH and the characteristics of these measures and methods. A systematic database search was conducted of CENTRAL; CINAHL; Cochrane; ERIC; Joanna Briggs; Linguistics, Language and Behavior Abstracts; Medline; Scopus; and Web of Science databases, as well as supplemental searches. A total of 204 included studies reported the use of many different measures/methods which measured segmental aspects of speech, with the most common being Allen et al.'s (2001, The reliability of a rating scale for measuring speech intelligibility following pediatric cochlear implantation. Otology and Neurotology, 22(5), 631-633. https://doi.org/10.1097/00129492-200109000-00012) Speech Intelligibility Rating scale. Many studies included insufficient details to determine the measure that was used. Future research should utilize methods/measures with known psychometric validity, provide clear descriptions of the methods/measures used, and consider using more than one measure to account for limitations inherent in different methods of measuring the speech intelligibility of children who are DHH, and consider and discuss the rationale for the measure/method chosen.

Spontaneous speech intelligibility: early cochlear implanted children versus their normally hearing peers at seven years of age

Speaking intelligibly is an important achievement in children's language development. How far do congenitally severe-to-profound hearing-impaired children who received a cochlear implant (CI) in the first two years of their life advance on the path to intelligibility in comparison to children with typical hearing (NH)? Spontaneous speech samples of children with CI and children with NH were orthographically transcribed by naïve transcribers. The entropy of the transcriptions was computed to analyze their degree of uniformity. The same samples were also rated on a continuous rating scale by another group of adult listeners. The transcriptions of the NH children's speech were more uniform, i.e., had significantly lower entropy, than those of the CI children, suggesting that the latter group displayed lower intelligibility. This was confirmed by the ratings on the continuous scale. Despite the relatively restricted age ranges, older children reached better intelligibility scores in both groups.

Development of fricative production in French-speaking school-aged children using cochlear implants and children with normal hearing

In the course of productive phonological development, fricatives are among the last speech sounds to emerge and to be mastered by children, probably because of the high degree of articulatory precision they require or because of difficulties with their perception. Children with cochlear implants (CI) face additional difficulties with fricative perception, since high spectral frequency components are shown to be especially difficult to perceive with a cochlear implant. Studying fricative production in children with CIs allows to study how the partial transmission of speech sounds by cochlear implants influences children's speech production, and therefore to explore how perceptual abilities influence the late stages of phonological development. This acoustic study focuses on fricative production at three places of articulation (i.e., /f/, /s/ and /ʃ/), comparing productions by two groups of children (20 children with normal hearing (NH) vs. 13 children with CIs, all aged 5;7 to 10;7 years), and taking into account their consistency in coarticulation and the stability of their production across two different tasks (word-repetition and picture-naming). Statistical analyses were carried out by means of linear mixed-effect models. The results show that while both groups produce /ʃ/ with similar acoustic characteristics, between-group differences are found for /f/ and /s/. Furthermore, effects of consonant-vowel coarticulation are found for children with NH, and are absent for children with CIs. Effects of chronological age are only found for children with CIs (production in older children with CIs nearing that of children with NH). Our study shows that the development of fricative production of five- to 11-year-old children with CIs is affected by the children's hearing abilities and late access to auditory information. These limitations however do not prevent the children from eventually reaching a consistency similar to that of children with NH, as suggested by the fact that their production is still evolving during that age span. The results also show that the acquisition of coarticulation strategies can be impeded by degraded or delayed access to audio.

Long-term effects of cochlear implantation on the intelligibility of speech in French-speaking children

Our study compares the intelligibility of French-speaking children with a cochlear implant (N = 13) and age-matched children with typical hearing (N = 13) in a narrative task. This contrasts with previous studies in which speech intelligibility of children with cochlear implants is most often tested using repetition or reading tasks. Languages other than English are seldom considered. Their productions were graded by naive and expert listeners. The results show that (1) children with CIs have lower intelligibility, (2) early implantation is a predictor of good intelligibility, and (3) late implantation after two years of age does not prevent the children from eventually reaching good intelligibility.

Is the spontaneous speech of 7-year-old cochlear implanted children as intelligible as that of their normally hearing peers?

OBJECTIVES

Studies on speech intelligibility usually focus on either individual words, sentences or longer sequences of speech. Since these different kinds of speech samples can be judged using different methodologies, a difference in the reported intelligibility scores can either be due to the difference in the type of sample or methodology. The present study compares the speech intelligibility of seven-year-old children with a cochlear implant (CI) with that of their normally hearing (NH) peers. The first aim is to compare the intelligibility of short sentences and longer sequences of speech using the same methodology. Secondly, it has been suggested that i.a. advances in CI technology and changes in candidacy criteria may have had a positive influence on the intelligibility of children with CI. In order to assess this issue, the intelligibility of seven-year-olds implanted ten years apart will be compared.

METHOD

The speech of two cohorts of early implanted children with CI (n = 16) and NH peers (n = 16), matched on several criteria but implanted in different years, was collected. More specifically, short and longer samples were selected from recordings of a wordless picture book retelling. Both types of samples were judged on a visual analogue scale by 105 inexperienced listeners.

RESULTS

The results showed that the intelligibility of children with CI was lower than that of their NH peers. Moreover, longer samples were significantly more intelligible than short samples for both groups. No significant effect was found between the two cohorts of children with CI. However, the intelligibility of three out of four children with CI was found to be on a par with that of their NH peers, indicating a large amount of variability between subjects.

CONCLUSION

Listeners ascribed higher intelligibility to longer samples than to short samples, despite the fact that both types were extracted from the same recordings and listeners followed the same judgement procedure. The amount of context thus facilitated speech decoding. No effect of the calendar year of implantation was found, suggesting that e.g., the evolution in CI technology did not have a significant impact on CI users' intelligibility after six years of device use.