The effect of speech degradation on the ability to track and predict turn structure in conversation.

Conversation represents a considerable amount of the daily language usage and plays an important role in language acquisition. In conversation, listeners simultaneously process their interlocutor's turn and prepare their own next turn. As such the turn-taking dynamics heavily relies on prediction. In other words, listeners avail prior knowledge to constrain both speech perception and production. Here we explored the relation between prediction and comprehension while watching two interlocutors having a conversation. We capitalize on gaze switch as a proxy of predictive behaviour to class dialogue turns as more or less well predicted and explore how this affects dialogue comprehension. Moreover, we study the extent to which speech degradation, by increasing the global uncertainty of the context, affects the relation between predictions, brain correlates of prediction errors (N400) and global comprehension. Results show that 1) listeners direct gaze to the current speaker, in particular in challenging conditions, 2) gaze behaviour possibly affects the semantic processing of the upcoming turn (N400), 3) participants with a more efficient gaze predictive behaviour better solve semantic uncertainties at the turn onset, in particular in the most challenging listening condition. Our findings contribute to a better understanding of the relation between predictions, neural predictions errors and speech comprehension under challenging conditions.

Does auditory deprivation impairs statistical learning in the auditory modality?

Early sensory deprivation allows assessing the extent of reorganisation of cognitive functions, well beyond sensory processing. As such, it is a good model to explore the links between sensory experience and cognitive functions. One of these functions, statistical learning - the ability to extract and use regularities present in the environment - is suspected to be impaired in prelingually deaf children with a cochlear implant. However, empirical evidence supporting this claim is very scarce and studies have reported contradictory results. This might be because previous studies have tested statistical learning only in the visual modality and did not make clear distinctions between multiple types of statistical regularities. To overcome these problems, we designed a modified serial reaction time task where cochlear implanted children and normal hearing children had to react to auditory sequences that embed multiple statistical regularities, namely transition probabilities of 0th, 1st or 2nd order. We compared the reaction times of the children with the output of a simple computational model that learns transition probabilities. First, 6-12 years old children were able to learn 0th and 1st order transition probabilities but not 2nd order ones. Second, there were no differences between cochlear implanted children and their normal hearing peers. These results indicate that auditory statistical learning is preserved in congenitally deaf children with cochlear implants. This suggests in turn that early auditory deprivation might not be crucially detrimental for the normal development of statistical learning.

Rhythmic Abilities of Children With Hearing Loss.

OBJECTIVES: Children with hearing loss (HL), in spite of early cochlear implantation, often struggle considerably with language acquisition. Previous research has shown a benefit of rhythmic training on linguistic skills in children with HL, suggesting that improving rhythmic capacities could help attenuating language difficulties. However, little is known about general rhythmic skills of children with HL and how they relate to speech perception. The aim of this study is twofold: (1) to assess the abilities of children with HL in different rhythmic sensorimotor synchronization tasks compared to a normal-hearing control group and (2) to investigate a possible relation between sensorimotor synchronization abilities and speech perception abilities in children with HL. DESIGN: A battery of sensorimotor synchronization tests with stimuli of varying acoustic and temporal complexity was used: a metronome, different musical excerpts, and complex rhythmic patterns. Synchronization abilities were assessed in 32 children (aged from 5 to 10 years) with a severe to profound HL mainly fitted with one or two cochlear implants (n = 28) or with hearing aids (n = 4). Working memory and sentence repetition abilities were also assessed. Performance was compared to an age-matched control group of 24 children with normal hearing. The comparison took into account variability in working memory capacities. For children with HL only, we computed linear regressions on speech, sensorimotor synchronization, and working memory abilities, including device-related variables such as onset of device use, type of device, and duration of use. RESULTS: Compared to the normal-hearing group, children with HL performed poorly in all sensorimotor synchronization tasks, but the effect size was greater for complex as compared to simple stimuli. Group differences in working memory did not explain this result. Linear regression analysis revealed that working memory, synchronization to complex rhythms performances, age, and duration of device use predicted the number of correct syllables produced in a sentence repetition task. CONCLUSION: Despite early cochlear implantation or hearing aid use, hearing impairment affects the quality of temporal processing of acoustic stimuli in congenitally deaf children. This deficit seems to be more severe with stimuli of increasing rhythmic complexity highlighting a difficulty in structuring sounds according to a temporal hierarchy.

Musical Training for Auditory Rehabilitation in Hearing Loss.

Despite the overall success of cochlear implantation, language outcomes remain suboptimal and subject to large inter-individual variability. Early auditory rehabilitation techniques have mostly focused on low-level sensory abilities. However, a new body of literature suggests that cognitive operations are critical for auditory perception remediation. We argue in this paper that musical training is a particularly appealing candidate for such therapies, as it involves highly relevant cognitive abilities, such as temporal predictions, hierarchical processing, and auditory-motor interactions. We review recent studies demonstrating that music can enhance both language perception and production at multiple levels, from syllable processing to turn-taking in natural conversation.

Rhythmic Training Improves Temporal Anticipation and Adaptation Abilities in Children With Hearing Loss During Verbal Interaction.

Purpose In this study, we investigate temporal adaptation capacities of children with normal hearing and children with cochlear implants and/or hearing aids during verbal exchange. We also address the question of the efficiency of a rhythmic training on temporal adaptation during speech interaction in children with hearing loss. Method We recorded electroencephalogram data in children while they named pictures delivered on a screen, in alternation with a virtual partner. We manipulated the virtual partner's speech rate (fast vs. slow) and the regularity of alternation (regular vs. irregular). The group of children with normal hearing was tested once, and the group of children with hearing loss was tested twice: once after 30 min of auditory training and once after 30 min of rhythmic training. Results Both groups of children adjusted their speech rate to that of the virtual partner and were sensitive to the regularity of alternation with a less accurate performance following irregular turns. Moreover, irregular turns elicited a negative event-related potential in both groups, showing a detection of temporal deviancy. Notably, the amplitude of this negative component positively correlated with accuracy in the alternation task. In children with hearing loss, the effect was more pronounced and long-lasting following rhythmic training compared with auditory training. Conclusion These results are discussed in terms of temporal adaptation abilities in speech interaction and suggest the use of rhythmic training to improve these skills of children with hearing loss.

Speak on time! Effects of a musical rhythmic training on children with hearing loss.

This study investigates temporal adaptation in speech interaction in children with normal hearing and in children with cochlear implants (CIs) and/or hearing aids (HAs). We also address the question of whether musical rhythmic training can improve these skills in children with hearing loss (HL). Children named pictures presented on the screen in alternation with a virtual partner. Alternation rate (fast or slow) and the temporal predictability (match vs mismatch of stress occurrences) were manipulated. One group of children with normal hearing (NH) and one with HL were tested. The latter group was tested twice: once after 30 min of speech therapy and once after 30 min of musical rhythmic training. Both groups of children (NH and with HL) can adjust their speech production to the rate of alternation of the virtual partner. Moreover, while children with normal hearing benefit from the temporal regularity of stress occurrences, children with HL become sensitive to this manipulation only after rhythmic training. Rhythmic training may help children with HL to structure the temporal flow of their verbal interactions.

Rhythmic priming enhances speech production abilities: evidence from prelingually deaf children.

OBJECTIVE: Following recent findings that rhythmic priming can enhance speech perception, the aim of this experiment was to investigate whether this extends to speech production. METHOD: The authors measured the influence of rhythmic priming on phonological production abilities in 14 hearing impaired children with hearing devices. Children had to repeat sentences that were or were not preceded by a rhythmical prime. In addition, this rhythmic prime either matched or mismatched the meter (i.e., stress contrasts) of the sentence. RESULTS: Matching conditions resulted in a greater phonological accuracy of spoken sentences compared to baseline and mismatching conditions. Cochlear implant users were also more sensitive to rhythmic priming than hearing aid users. CONCLUSIONS: These results suggest that musical rhythmic priming can enhance phonological production in HI children via an enhanced perception of the target sentence. Overall, these findings suggest that musical rhythm engages domain-general expectations which can enhance both in perception and production of speech.