Early experience of Cued Speech enhances speechreading performance in deaf

Exposure to Canadian French Cued Speech Improves Consonant Articulation in Children With Cochlear Implants: Acoustic and Articulatory Data

PURPOSE

One of the strategies that can be used to support speech communication in deaf children is cued speech, a visual code in which manual gestures are used as additional phonological information to supplement the acoustic and labial speech information. Cued speech has been shown to improve speech perception and phonological skills. This exploratory study aims to assess whether and how cued speech reading proficiency may also have a beneficial effect on the acoustic and articulatory correlates of consonant production in children.

METHOD

Eight children with cochlear implants (from 5 to 11 years of age) and with different receptive proficiency in Canadian French Cued Speech (three children with low receptive proficiency vs. five children with high receptive proficiency) are compared to 10 children with typical hearing (from 4 to 11 years of age) on their production of stop and fricative consonants. Articulation was assessed with ultrasound measurements.

RESULTS

The preliminary results reveal that cued speech proficiency seems to sustain the development of speech production in children with cochlear implants and to improve their articulatory gestures, particularly for the place contrast in stops as well as fricatives.

CONCLUSION

This work highlights the importance of studying objective data and comparing acoustic and articulatory measurements to better characterize speech production in children.

Factors Affecting Visual-Only Speech Recognition in Individuals With Cochlear Implants

Objectives: Several reports have underlined the benefits of speechreading (visual-only speech recognition) on speech recognition in individuals with hearing loss after cochlear implantation (CI). However, the factors that would affect the ability of speechreading are unclear. The aim of the present study is to assess the factors that affect speechreading abilities in CI users. Methods: A total of 104 participants were enrolled in this retrospective study. They viewed silent videos of sentences being spoken by a model and were tasked with repeating what they thought had been said. They were tested under audio-only and visual-only conditions. Factors (such as the age, the age of CI; <3 years old vs 3-8 years old; male vs female, etc) believed to affect speechreading abilities were analyzed. Results: The age range of the participants is 8 to 34 years. CI users showed significantly different speechreading abilities among themselves. The authors found that age and hearing loss at 3 to 8 years of age were positively related to superior speechreading recognition scores. Conclusions: CI users followed a more complex method of perceptual compensation. Those who have suffered hearing loss between 3 and 8 years of age are more sensitive to developing an advantage in speech recognition by using speechreading. Older age positively affects speechreading abilities; thus, the more experience CI has, the greater speechreading ability they may exhibit.

Speech rehabilitation in children with cochlear implants using a multisensory (French Cued Speech) or a hearing-focused (Auditory Verbal Therapy) approach

Introduction

Early exposure to a rich linguistic environment is essential as soon as the diagnosis of deafness is made. Cochlear implantation (CI) allows children to have access to speech perception in their early years. However, it provides only partial acoustic information, which can lead to difficulties in perceiving some phonetic contrasts. This study investigates the contribution of two spoken speech and language rehabilitation approaches to speech perception in children with CI using a lexicality judgment task from the EULALIES battery. Auditory Verbal Therapy (AVT) is an early intervention program that relies on auditory learning to enhance hearing skills in deaf children with CI. French Cued Speech, also called Cued French (CF), is a multisensory communication tool that disambiguates lip reading by adding a manual gesture.

Methods

In this study, 124 children aged from 60 to 140 months were included: 90 children with typical hearing skills (TH), 9 deaf children with CI who had participated in an AVT program (AVT), 6 deaf children with CI with high Cued French reading skills (CF+), and 19 deaf children with CI with low Cued French reading skills (CF-). Speech perception was assessed using sensitivity (d') using both the hit and false alarm rates, as defined in signal-detection theory.

Results

The results show that children with cochlear implants from the CF- and CF+ groups have significantly lower performance compared to children with typical hearing (TH) (p < 0.001 and p = 0.033, respectively). Additionally, children in the AVT group also tended to have lower scores compared to TH children (p = 0.07). However, exposition to AVT and CF seems to improve speech perception. The scores of the children in the AVT and CF+ groups are closer to typical scores than those of children in the CF- group, as evidenced by a distance measure.

Discussion

Overall, the findings of this study provide evidence for the effectiveness of these two speech and language rehabilitation approaches, and highlight the importance of using a specific approach in addition to a cochlear implant to improve speech perception in children with cochlear implants.

Cued Speech Enhances Speech-in-Noise Perception

Speech perception in noise remains challenging for Deaf/Hard of Hearing people (D/HH), even fitted with hearing aids or cochlear implants. The perception of sentences in noise by 20 implanted or aided D/HH subjects mastering Cued Speech (CS), a system of hand gestures complementing lip movements, was compared with the perception of 15 typically hearing (TH) controls in three conditions: audio only, audiovisual, and audiovisual + CS. Similar audiovisual scores were obtained for signal-to-noise ratios (SNRs) 11 dB higher in D/HH participants compared with TH ones. Adding CS information enabled D/HH participants to reach a mean score of 83% in the audiovisual + CS condition at a mean SNR of 0 dB, similar to the usual audio score for TH participants at this SNR. This confirms that the combination of lipreading and Cued Speech system remains extremely important for persons with hearing loss, particularly in adverse hearing conditions.

The Neural Basis of Speech Perception through Lipreading and Manual Cues: Evidence from Deaf Native Users of Cued Speech

We present here the first neuroimaging data for perception of Cued Speech (CS) by deaf adults who are native users of CS. CS is a visual mode of communicating a spoken language through a set of manual cues which accompany lipreading and disambiguate it. With CS, sublexical units of the oral language are conveyed clearly and completely through the visual modality without requiring hearing. The comparison of neural processing of CS in deaf individuals with processing of audiovisual (AV) speech in normally hearing individuals represents a unique opportunity to explore the similarities and differences in neural processing of an oral language delivered in a visuo-manual vs. an AV modality. The study included deaf adult participants who were early CS users and native hearing users of French who process speech audiovisually. Words were presented in an event-related fMRI design. Three conditions were presented to each group of participants. The deaf participants saw CS words (manual + lipread), words presented as manual cues alone, and words presented to be lipread without manual cues. The hearing group saw AV spoken words, audio-alone and lipread-alone. Three findings are highlighted. First, the middle and superior temporal gyrus (excluding Heschl's gyrus) and left inferior frontal gyrus pars triangularis constituted a common, amodal neural basis for AV and CS perception. Second, integration was inferred in posterior parts of superior temporal sulcus for audio and lipread information in AV speech, but in the occipito-temporal junction, including MT/V5, for the manual cues and lipreading in CS. Third, the perception of manual cues showed a much greater overlap with the regions activated by CS (manual + lipreading) than lipreading alone did. This supports the notion that manual cues play a larger role than lipreading for CS processing. The present study contributes to a better understanding of the role of manual cues as support of visual speech perception in the framework of the multimodal nature of human communication.

Speechreading in Deaf Adults with Cochlear Implants: Evidence for Perceptual Compensation

Previous research has provided evidence for a speechreading advantage in congenitally deaf adults compared to hearing adults. A 'perceptual compensation' account of this finding proposes that prolonged early onset deafness leads to a greater reliance on visual, as opposed to auditory, information when perceiving speech which in turn results in superior visual speech perception skills in deaf adults. In the current study we tested whether previous demonstrations of a speechreading advantage for profoundly congenitally deaf adults with hearing aids, or no amplificiation, were also apparent in adults with the same deafness profile but who have experienced greater access to the auditory elements of speech via a cochlear implant (CI). We also tested the prediction that, in line with the perceptual compensation account, receiving a CI at a later age is associated with superior speechreading skills due to later implanted individuals having experienced greater dependence on visual speech information. We designed a speechreading task in which participants viewed silent videos of 123 single words spoken by a model and were required to indicate which word they thought had been said via a free text response. We compared congenitally deaf adults who had received CIs in childhood or adolescence (N = 15) with a comparison group of hearing adults (N = 15) matched on age and education level. The adults with CI showed significantly better scores on the speechreading task than the hearing comparison group. Furthermore, within the group of adults with CI, there was a significant positive correlation between age at implantation and speechreading performance; earlier implantation was associated with lower speechreading scores. These results are both consistent with the hypothesis of perceptual compensation in the domain of speech perception, indicating that more prolonged dependence on visual speech information in speech perception may lead to improvements in the perception of visual speech. In addition our study provides metrics of the 'speechreadability' of 123 words produced in British English: one derived from hearing adults (N = 61) and one from deaf adults with CI (N = 15). Evidence for the validity of these 'speechreadability' metrics come from correlations with visual lexical competition data.

Audiovisual spoken word training can promote or impede auditory-only perceptual learning: prelingually deafened adults with late-acquired cochlear implants versus normal hearing adults

Training with audiovisual (AV) speech has been shown to promote auditory perceptual learning of vocoded acoustic speech by adults with normal hearing. In Experiment 1, we investigated whether AV speech promotes auditory-only (AO) perceptual learning in prelingually deafened adults with late-acquired cochlear implants. Participants were assigned to learn associations between spoken disyllabic C(=consonant)V(=vowel)CVC non-sense words and non-sense pictures (fribbles), under AV and then AO (AV-AO; or counter-balanced AO then AV, AO-AV, during Periods 1 then 2) training conditions. After training on each list of paired-associates (PA), testing was carried out AO. Across all training, AO PA test scores improved (7.2 percentage points) as did identification of consonants in new untrained CVCVC stimuli (3.5 percentage points). However, there was evidence that AV training impeded immediate AO perceptual learning: During Period-1, training scores across AV and AO conditions were not different, but AO test scores were dramatically lower in the AV-trained participants. During Period-2 AO training, the AV-AO participants obtained significantly higher AO test scores, demonstrating their ability to learn the auditory speech. Across both orders of training, whenever training was AV, AO test scores were significantly lower than training scores. Experiment 2 repeated the procedures with vocoded speech and 43 normal-hearing adults. Following AV training, their AO test scores were as high as or higher than following AO training. Also, their CVCVC identification scores patterned differently than those of the cochlear implant users. In Experiment 1, initial consonants were most accurate, and in Experiment 2, medial consonants were most accurate. We suggest that our results are consistent with a multisensory reverse hierarchy theory, which predicts that, whenever possible, perceivers carry out perceptual tasks immediately based on the experience and biases they bring to the task. We point out that while AV training could be an impediment to immediate unisensory perceptual learning in cochlear implant patients, it was also associated with higher scores during training.

Phonetic processing during the acquisition of new words in 3-to-6-year-old French-speaking deaf children with cochlear implants

The present study explores phonetic processing in deaf children with cochlear implants (CIs) when they have to learn phonetically similar words. Forty-six 34-to-78-month-old French-speaking deaf children with CIs were tested on 16 different trials. In each trial, they were first trained with two word-object pairings, and then a third object was presented and labeled with one of the familiar words. Children were asked to match one of the previously labeled objects with the third (same-labeled) object. Each pair of words contrasted on either the initial consonant or the first vowel by one or several phonetic features. The results show that deaf children with CIs are able to establish a new referential link between a word and an object. However, their performance is lower than that previously observed in normal-hearing children (NH). In such a situation, they process contrasts involving several phonetic features correctly, but show difficulties with minimal contrasts. The ability to recruit fine phonetic sensitivity during word learning appears to be influenced mainly by duration of implant use, with an overall increase of performance during the 3 years after implantation. There was no chronological age effect, nor age at implantation effect on the quality of processing. Difficulty with minimal contrasts and the absence of any age at implantation effects in this age range are discussed in light of recent studies on lexical development.

LEARNING OUTCOMES

After reading this article, the reader will be able to recognize the perceptual skills of children with cochlear implants and distinguish those perceptual features that are difficult for the children to perceive.