A comparison of vowel production by children with multichannel cochlear implants or tactile aids: perceptual evidence

Effect of telepractice on pediatric cochlear implant users and provider vowel space: A preliminary report

Clear speaking styles are goal-oriented modifications in which talkers adapt acoustic-phonetic characteristics of speech to compensate for communication challenges. Do children with hearing loss and a clinical provider modify speech characteristics during telepractice to adjust for remote communication? The study examined the effect of telepractice (tele-) on vowel production in seven (mean age 4:11 years, SD 1:2 years) children with cochlear implants (CIs) and a provider. The first (F1) and second (F2) formant frequencies of /i/, /ɑ/, and /u/ vowels were measured in child and provider speech during one in-person and one tele-speech-language intervention, order counterbalanced. Child and provider vowel space areas (VSA) were calculated. The results demonstrated an increase in F2 formant frequency for /i/ vowel in child and provider speech and an increase in F1 formant frequency for /ɑ/ vowel in the provider speech during tele- compared to in-person intervention. An expansion of VSA was found in child and provider speech in tele- compared to in-person intervention. In children, the earlier age of CI activation was associated with larger VSA in both tele- and in-person intervention. The results suggest that the children and the provider adjust vowel articulation in response to remote communication during telepractice.

Phoneme acquisition in French-speaking children with moderate hearing loss

The current study aims to provide a more precise understanding of phoneme acquisition by children with moderate hearing loss (MHL), since they have been an under-studied population among children with hearing loss. The acquisition of sounds by 15 children with MHL (mean: 3;11 year-old) was compared to that by six younger normal-hearing (YNH) children (mean: 2;8 year-old). All the children were video- and audio-recorded in interaction with one or both parents in two semi-spontaneous tasks, and during a naming task. All their productions were analysed in terms of percentage of accuracy and substitution patterns. Similarities and differences between the two populations were observed. Globally, the phoneme level of accuracy of children with MHL was similar to that of YNH, but with a general delay. The observation of substitution patterns revealed differences between the two populations, such as prevalent fortition of fricatives and /ʁ/ by children with MHL, which was unusual among YNH children. Another difference was the prevalent posteriorization of coronal fricatives by children with MHL, whereas anteriorization of post-alveolar fricatives was more common in YNH children. These findings highlight the role of perception and language experience in phonological acquisition, showing that an atypical hearing experience may not only cause a delay, but also the emergence of a specific developmental path.

A comparison of the consonant production between Dutch children using cochlear implants and children using hearing aids

OBJECTIVES

The main purpose of the present study was to compare the consonant error patterns of Dutch prelingually deaf CI children with prelingually hearing-impaired hearing aid (HA) children. The authors hypothesized that subjects using conventional hearing aids would have poorer consonant production skills. Additionally, the impact of the age at implantation (CI) and the degree of hearing loss (HA) was determined.

METHODOLOGY

This is a comparative study of 29 prelingually deaf CI children (m.a. 9;0 y) and 32 prelingually hearing-impaired HA children (m.a. 9;11 y) who received their first hearing aid before the age of 2 years. Nineteen CI children were implanted before the age of 5 years. Nine HA children had thresholds above 90dB (range: 91-105dB), 15 between 70 and 90dB (range: 72-90dB) and 8 below 70dB (range: 58-68dB). Speech samples of all the children were elicited by means of a picture naming test and were video-recorded for further phonetic and phonological analysis.

RESULTS

Considerably more phonetic and phonologic errors were observed in the HA children with thresholds above 70dB (range: 72-105dB). No notable differences could be found between deaf CI children and HA children with thresholds below 70dB. Even children implanted after the age of 5 years showed significantly fewer phonetic and phonological errors than HA children.

CONCLUSION

The consonant production of implanted children is more adequate than the consonant production of HA children with a hearing loss of 70dB or more. In addition, the results also indicate that even after the age of 5 years, implantation can still have an advantageous effect on a child's consonant production.

Fortition and lenition patterns in the acquisition of obstruents by children with cochlear implants

This paper investigates patterns of error production in 10 children who use cochlear implants, focusing specifically on the acquisition of obstruents. Two broad patterns of production errors are investigated, fortition (or strengthening) errors and lenition (or weakening) errors. It is proposed that fortition error patterns tend to be related to the process of phonological development, because they are involved with universal implications and notions of markedness. Lenition error patterns, on the other hand, show more context-sensitive effects and reflect properties related to minimization of articulatory effort. The relationship between fortition and markedness is demonstrated in an optimality theoretic analysis, and it is further demonstrated that the observed characteristics of phonological development in children with cochlear implants are similar to those exhibited by children with normal hearing.

Production of consonants by prelinguistically deaf children with cochlear implants

Consonant production following the sensory restoration of audition was investigated in 22 prelinguistically deaf French children who received cochlear implants. Spontaneous speech productions were recorded at 6, 12, and 18 months post-surgery and consonant inventories were derived from both glossable and non-glossable phones using two acquisition criteria. The results showed that children initiated appropriate production of consonants after six months of implant use. Stops and labials were the most frequently produced speech sounds, whereas glides and palatals were still infrequent after 18 months. Speech accuracy also improved throughout the study. Consonant visibility appeared to influence the order of acquisition in the first months following the implantation and, as experience with auditory information increased, patterns of development tended to resemble those seen in children with normal hearing. Finally, a signed mode of communication and oral rehabilitation programs prior to implantation were better outcome predictors than age at implantation.

Prosody and voice characteristics of children with cochlear implants

This descriptive, longitudinal study involved the analysis of the prosody and voice characteristics of conversational speech produced by six young children with severe to profound hearing impairments who had been fitted with cochlear implants. A total of 40 samples were analyzed using the Prosody-Voice Screening Profile (PVSP; Shriberg, L. D., Kwiatkowski, J., & Rasmussen, C. (1990). Prosody-Voice Screening Profile (PVSP). Tuscon, AZ: Communication Skill Builders). Overall, the children presented with noticeable problems with stress and resonance quality. There were some difficulties noted with rate, loudness, and laryngeal quality, but there were no consistent difficulties with phrasing or pitch. This suggested that prosody and voice characteristics in this population are different from those typically observed in children with severe to profound hearing impairments though some problem areas remain. Some developmental trends were also observed. These findings suggest that cochlear implants offer some significant benefits to children with hearing impairment in terms of prosody and voice outcomes.

Acoustic analysis of monophthong and diphthong production in acquired severe to profound hearing loss

The effect of diminished auditory feedback on monophthong and diphthong production was examined in postlingually deafened Australian-English speaking adults. The participants were 4 female and 3 male speakers with severe to profound hearing loss, who were compared to 11 age- and accent-matched normally hearing speakers. The test materials were 5 repetitions of hVd words containing 18 vowels. Acoustic measures that were studied included F1, F2, discrete cosine transform coefficients (DCTs), and vowel duration information. The durational analyses revealed increased total vowel durations with a maintenance of the tense/lax vowel distinctions in the deafened speakers. The deafened speakers preserved a differentiated vowel space, although there were some gender-specific differences seen. For example, there was a retraction of F2 in the front vowels for the female speakers that did not occur in the males. However, all deafened speakers showed a close correspondence between the monophthong and diphthong formant movements that did occur. Gaussian classification highlighted vowel confusions resulting from changes in the deafened vowel space. The results support the view that postlingually deafened speakers maintain reasonably good speech intelligibility, in part by employing production strategies designed to bolster auditory feedback.

Children's consonant inventories after extended cochlear implant use

Qualitative descriptions of the consonant inventories of 12 children who have used cochlear implants for at least 5 years are provided, together with description of sound correspondences between children's systems and the ambient language (English). Productions of English words were elicited in a picture-naming task, and a consonant inventory for each child was determined. Results showed that the consonant inventories of children who use cochlear implants are not simply subsets of the inventory of the ambient language, but rather unique sets of segments that may include consonants not in the ambient inventory. Comparison of the inventories of oral communication users and total communication users revealed qualitative differences between the 2 groups, based on the presence or absence of both English and non-English sound segments. Inventories of oral communication users tended to contain more English segments (e.g., alveolar fricatives, velar stops, velar nasals) than did the inventories of total communication users. Conversely, specific non-English segments, such as uvular stops, tended to occur in the inventories of total communication users more than in inventories of oral communication users. Therefore, a complete understanding of the phonological systems of children who use cochlear implants depends on full accounts of their segment inventories. Such understanding may affect decisions regarding habilitation procedures, insofar as successful acquisition of a linguistic system involves not only the inclusion of all ambient sound segments, but also the exclusion of all nonambient ones.

Changes in speech production in a child with a cochlear implant: acoustic and kinematic evidence

A method is presented for examining change in motor patterns used to produce linguistic contrasts. In this case study, the method is applied to a child receiving new auditory input following cochlear implantation. This child experienced hearing loss at age 3 years and received a multichannel cochlear implant at age 7 years. Data collection points occurred both pre- and postimplant and included acoustic and kinematic analyses. Overall, this child's speech output was transcribed as accurate across the pre- and postimplant periods. Postimplant, with the onset of new auditory experience, acoustic durations showed a predictable maturational change, usually decreasing in duration. Conversely, the spatiotemporal stability of speech movements initially became more variable postimplantation. The auditory perturbations experienced by this child during development led to changes in the physiological underpinnings of speech production, even when speech output was perceived as accurate.

Aspects of Stop Consonant Production by Pediatric Users of Cochlear Implants

Purpose: Data and analyses are reported for stop consonant production by 12 children who have used cochlear implants for at least 5 years, focusing on variation within and between individual phonological systems.

Method: Participants were 6 oral communication users and 6 total communication users. Productions of single words were analyzed for stop inventories, phonotactic constraints, and morphophonemic alternations. Variation was further analyzed within optimality theory.

Results: Children’s inventories differed from English mainly in having additional, non-English stops. Total communication users had fewer ambient stops and more nonambient ones than did oral communication users. Control over English allophonic and neutralization rules varied among children. Phonological variation could be accounted for by positing unique underlying representations and different constraint rankings within optimality theory.

Clinical Implications: Atypical speech by children with cochlear implants involves both articulation and phonological organization. Although children vary considerably, characteristic patterns emerge. An understanding of these patterns is useful for identifying areas of difficulty and formulating intervention programs.

Emergence of a vowel system in a young cochlear implant recipient

This report chronicles changes in vowel production by a congenitally deaf child who received a multichannel cochlear implant at 19 months. The emergence of Hannah's vowel system was monitored by transcribing vocalic segments from spontaneous utterances produced during two 30-minute recording sessions before implant surgery and 12 monthly recording sessions after her implant was activated. Vowel types were included in her inventory whenever transcribers independently agreed that a vocalization contained an allophone of a given vowel type. Hannah exhibited three vowel types before implantation. A total of nine different vowel types were observed during her first year of implant experience, and a full range of place and height categories was represented. Acoustic analyses revealed that Hannah's vowel space was near normal in size and that the formant structures of /i/ and /u/ were distinctive from other point vowels. Formant regions for /ae/ and /a/ showed some overlap. Taken together with a previous report of her vocal development (D. J. Ertmer & J. A. Mellon, 2001), Hannah appears to have made substantial progress in speech development during her first year of implant use.

A phonological system at 2 years after cochlear implantation

This report is a description of a developing phonological system as manifested in the productions of a prelingually deafened child approximately 2 years after fitting with a Nucleus 22-Channel Multi-Electrode Cochlear Implant. A probe list consisting of 23 proper nouns familiar to the child was used to elicit samples of her speech; stimulus materials consisted of photographs of those persons (friends and family members) whose names were included in the probe list. Analysis of the child's productions addressed the composition of the phonetic inventory of consonants and vowels and the presence of syllable structure and other phonotactic constraints. Results indicated a rich inventory of speech sound segments (among both consonants and vowels) and a lack of stringent constraints on syllable structure and consonants permitted in specified word positions. A further comparative analysis of correspondences with the ambient language showed a number of patterns that are also common in the speech of children with normal hearing.

Imitative consonant feature production by children with multichannel sensory aids

OBJECTIVE

To examine changes over time in consonant feature production by children with profound hearing impairments who used either the Nucleus multichannel cochlear implant or the multichannel vibrotactile aid, Tactaid 7.

DESIGN

Imitative consonant productions of children with prelingual deafness were elicited and transcribed at two intervals: 1) before receiving their respective devices (predevice interval), and 2) after an average of 1.5 yr of device use (postdevice interval). The consonant productions were analyzed in terms of the percentage of consonant features (manner, place, and voicing) produced by the child that matched the features of the examiner's target. The percentage of features produced correctly was then averaged across repetitions, vowel environments, and participants within each group.

RESULTS

At the predevice interval, the cochlear implant and Tactaid 7 participants demonstrated similar imitative consonant production abilities. After an average of 1.5 yr of device use, the cochlear implant participants demonstrated significantly greater gains than did the Tactaid 7 participants for the features of voicing and place of articulation. Although the cochlear implant participants showed a trend towards better production of the consonant manner features, this difference failed to reach significance.

CONCLUSIONS

The current results suggest that the use of a multichannel sensory aid yields improvements in consonant feature production. Furthermore, use of a cochlear implant appears to promote the production of consonant voicing and place features to a greater degree than does the use of a multichannel tactile aid.