Audiovisual speech perception in children with developmental language disorder in degraded listening conditions

Speechreading, Phonological Skills, and Word Reading Ability in Children

PURPOSE

The purpose of the present study was to investigate the relationship between speechreading ability, phonological skills, and word reading ability in typically developing children.

METHOD

Sixty-six typically developing children (6-7 years old) completed tasks measuring word reading, speechreading (words, sentences, and short stories), alliteration awareness, rhyme awareness, nonword reading, and rapid automatized naming (RAN).

RESULTS

Speechreading ability was significantly correlated with rhyme and alliteration awareness, phonological error rate, nonword reading, and reading ability (medium effect sizes) and RAN (small effect size). Multiple regression analyses showed that speechreading was not a unique predictor of word reading ability beyond the contribution of phonological skills. A speechreading error analysis revealed that children tended to use a phonological strategy when speechreading, and in particular, this strategy was used by skilled speechreaders.

CONCLUSIONS

The current study provides converging evidence that speechreading and phonological skills are positively related in typically developing children. These skills are likely to have a reciprocal relationship, and children may benefit from having their attention drawn to visual information available on the lips while learning letter sounds or learning to read, as this could augment and strengthen underlying phonological representations.

Audiovisual multisensory integration in individuals with reading and language impairments: A systematic review and meta-analysis

Differences in sensory function have been documented for a number of neurodevelopmental conditions, including reading and language impairments. Prior studies have measured audiovisual multisensory integration (i.e., the ability to combine inputs from the auditory and visual modalities) in these populations. The present study sought to systematically review and quantitatively synthesize the extant literature on audiovisual multisensory integration in individuals with reading and language impairments. A comprehensive search strategy yielded 56 reports, of which 38 were used to extract 109 group difference and 68 correlational effect sizes. There was an overall difference between individuals with reading and language impairments and comparisons on audiovisual integration. There was a nonsignificant trend towards moderation according to sample type (i.e., reading versus language) and publication/small study bias for this model. Overall, there was a small but non-significant correlation between metrics of audiovisual integration and reading or language ability; this model was not moderated by sample or study characteristics, nor was there evidence of publication/small study bias. Limitations and future directions for primary and meta-analytic research are discussed.

Impaired Audiovisual Representation of Phonemes in Children with Developmental Language Disorder

We examined whether children with developmental language disorder (DLD) differed from their peers with typical development (TD) in the degree to which they encode information about a talker’s mouth shape into long-term phonemic representations. Children watched a talker’s face and listened to rare changes from [i] to [u] or the reverse. In the neutral condition, the talker’s face had a closed mouth throughout. In the audiovisual violation condition, the mouth shape always matched the frequent vowel, even when the rare vowel was played. We hypothesized that in the neutral condition no long-term audiovisual memory traces for speech sounds would be activated. Therefore, the neural response elicited by deviants would reflect only a violation of the observed audiovisual sequence. In contrast, we expected that in the audiovisual violation condition, a long-term memory trace for the speech sound/lip configuration typical for the frequent vowel would be activated. In this condition then, the neural response elicited by rare sound changes would reflect a violation of not only observed audiovisual patterns but also of a long-term memory representation for how a given vowel looks when articulated. Children pressed a response button whenever they saw a talker’s face assume a silly expression. We found that in children with TD, rare auditory changes produced a significant mismatch negativity (MMN) event-related potential (ERP) component over the posterior scalp in the audiovisual violation condition but not in the neutral condition. In children with DLD, no MMN was present in either condition. Rare vowel changes elicited a significant P3 in both groups and conditions, indicating that all children noticed auditory changes. Our results suggest that children with TD, but not children with DLD, incorporate visual information into long-term phonemic representations and detect violations in audiovisual phonemic congruency even when they perform a task that is unrelated to phonemic processing.

Auditory processing in children: Role of working memory and lexical ability in auditory closure

We examined the relationship between cognitive-linguistic mechanisms and auditory closure ability in children. Sixty-seven school-age children recognized isolated words and keywords in sentences that were interrupted at a rate of 2.5 Hz and 5 Hz. In essence, children were given only 50% of speech information and asked to repeat the complete word or sentence. Children’s working memory capacity (WMC), attention, lexical knowledge, and retrieval from long-term memory (LTM) abilities were also measured to model their role in auditory closure ability. Overall, recognition of monosyllabic words and lexically easy multisyllabic words was significantly better at 2.5 Hz interruption rate than 5 Hz. Recognition of lexically hard multisyllabic words and keywords in sentences was better at 5 Hz relative to 2.5 Hz. Based on the best fit generalized “logistic” linear mixed effects models, there was a significant interaction between WMC and lexical difficulty of words. WMC was positively related only to recognition of lexically easy words. Lexical knowledge was found to be crucial for recognition of words and sentences, regardless of interruption rate. In addition, LTM retrieval ability was significantly associated with sentence recognition. These results suggest that lexical knowledge and the ability to retrieve information from LTM is crucial for children’s speech recognition in adverse listening situations. Study findings make a compelling case for the assessment and intervention of lexical knowledge and retrieval abilities in children with listening difficulties.

Individual differences in the acquisition of non-linguistic audio-visual associations in 5 year olds

Audio-visual associative learning - at least when linguistic stimuli are employed - is known to rely on core linguistic skills such as phonological awareness. Here we ask whether this would also be the case in a task that does not manipulate linguistic information. Another question of interest is whether executive skills, often found to support learning, may play a larger role in a non-linguistic audio-visual associative task compared to a linguistic one. We present a new task that measures learning when having to associate non-linguistic auditory signals with novel visual shapes. Importantly, our novel task shares with linguistic processes such as reading acquisition the need to associate sounds with arbitrary shapes. Yet, rather than phonemes or syllables, it uses novel environmental sounds - therefore limiting direct reliance on linguistic abilities. Five-year-old French-speaking children (N = 76, 39 girls) were assessed individually in our novel audio-visual associative task, as well as in a number of other cognitive tasks evaluating linguistic abilities and executive functions. We found phonological awareness and language comprehension to be related to scores in the audio-visual associative task, while no correlation with executive functions was observed. These results underscore a key relation between foundational language competencies and audio-visual associative learning, even in the absence of linguistic input in the associative task.

Auditory–Visual Speech Integration in Bipolar Disorder: A Preliminary Study

This study aimed to investigate how individuals with bipolar disorder integrate auditory and visual speech information compared to healthy individuals. Furthermore, we wanted to see whether there were any differences between manic and depressive episode bipolar disorder patients with respect to auditory and visual speech integration. It was hypothesized that the bipolar group’s auditory–visual speech integration would be weaker than that of the control group. Further, it was predicted that those in the manic phase of bipolar disorder would integrate visual speech information more robustly than their depressive phase counterparts. To examine these predictions, a McGurk effect paradigm with an identification task was used with typical auditory–visual (AV) speech stimuli. Additionally, auditory-only (AO) and visual-only (VO, lip-reading) speech perceptions were also tested. The dependent variable for the AV stimuli was the amount of visual speech influence. The dependent variables for AO and VO stimuli were accurate modality-based responses. Results showed that the disordered and control groups did not differ in AV speech integration and AO speech perception. However, there was a striking difference in favour of the healthy group with respect to the VO stimuli. The results suggest the need for further research whereby both behavioural and physiological data are collected simultaneously. This will help us understand the full dynamics of how auditory and visual speech information are integrated in people with bipolar disorder.

Audiovisual speech perception: A new approach and implications for clinical populations

This selected overview of audiovisual (AV) speech perception examines the influence of visible articulatory information on what is heard. Thought to be a cross-cultural phenomenon that emerges early in typical language development, variables that influence AV speech perception include properties of the visual and the auditory signal, attentional demands, and individual differences. A brief review of the existing neurobiological evidence on how visual information influences heard speech indicates potential loci, timing, and facilitatory effects of AV over auditory only speech. The current literature on AV speech in certain clinical populations (individuals with an autism spectrum disorder, developmental language disorder, or hearing loss) reveals differences in processing that may inform interventions. Finally, a new method of assessing AV speech that does not require obvious cross-category mismatch or auditory noise was presented as a novel approach for investigators.

Lipreading Ability and Its Cognitive Correlates in Typically Developing Children and Children With Specific Language Impairment

PURPOSE

Lipreading and its cognitive correlates were studied in school-age children with typical language development and delayed language development due to specific language impairment (SLI).

METHOD

Forty-two children with typical language development and 20 children with SLI were tested by using a word-level lipreading test and an extensive battery of standardized cognitive and linguistic tests.

RESULTS

Children with SLI were poorer lipreaders than their typically developing peers. Good phonological skills were associated with skilled lipreading in both typically developing children and in children with SLI. Lipreading was also found to correlate with several cognitive skills, for example, short-term memory capacity and verbal motor skills.

CONCLUSIONS

Speech processing deficits in SLI extend also to the perception of visual speech. Lipreading performance was associated with phonological skills. Poor lipreading in children with SLI may be, thus, related to problems in phonological processing.

Atypical audiovisual word processing in school-age children with a history of specific language impairment: an event-related potential study

Background

Visual speech cues influence different aspects of language acquisition. However, whether developmental language disorders may be associated with atypical processing of visual speech is unknown. In this study, we used behavioral and ERP measures to determine whether children with a history of SLI (H-SLI) differ from their age-matched typically developing (TD) peers in the ability to match auditory words with corresponding silent visual articulations.

Methods

Nineteen 7–13-year-old H-SLI children and 19 age-matched TD children participated in the study. Children first heard a word and then saw a speaker silently articulating a word. In half of trials, the articulated word matched the auditory word (congruent trials), while in another half, it did not (incongruent trials). Children specified whether the auditory and the articulated words matched. We examined ERPs elicited by the onset of visual stimuli (visual P1, N1, and P2) as well as ERPs elicited by the articulatory movements themselves—namely, N400 to incongruent articulations and late positive complex (LPC) to congruent articulations. We also examined whether ERP measures of visual speech processing could predict (1) children’s linguistic skills and (2) the use of visual speech cues when listening to speech-in-noise (SIN).

Results

H-SLI children were less accurate in matching auditory words with visual articulations. They had a significantly reduced P1 to the talker’s face and a smaller N400 to incongruent articulations. In contrast, congruent articulations elicited LPCs of similar amplitude in both groups of children. The P1 and N400 amplitude was significantly correlated with accuracy enhancement on the SIN task when seeing the talker’s face.

Conclusions

H-SLI children have poorly defined correspondences between speech sounds and visually observed articulatory movements that produce them.

Matching heard and seen speech: An ERP study of audiovisual word recognition

Seeing articulatory gestures while listening to speech-in-noise (SIN) significantly improves speech understanding. However, the degree of this improvement varies greatly among individuals. We examined a relationship between two distinct stages of visual articulatory processing and the SIN accuracy by combining a cross-modal repetition priming task with ERP recordings. Participants first heard a word referring to a common object (e.g., pumpkin) and then decided whether the subsequently presented visual silent articulation matched the word they had just heard. Incongruent articulations elicited a significantly enhanced N400, indicative of a mismatch detection at the pre-lexical level. Congruent articulations elicited a significantly larger LPC, indexing articulatory word recognition. Only the N400 difference between incongruent and congruent trials was significantly correlated with individuals' SIN accuracy improvement in the presence of the talker's face.

Visual Speech Perception in Children With Language Learning Impairments

PURPOSE

The purpose of the study was to assess the ability of children with developmental language learning impairments (LLIs) to use visual speech cues from the talking face.

METHOD

In this cross-sectional study, 41 typically developing children (mean age: 8 years 0 months, range: 4 years 5 months to 11 years 10 months) and 27 children with diagnosed LLI (mean age: 8 years 10 months, range: 5 years 2 months to 11 years 6 months) completed a silent speechreading task and a speech-in-noise task with and without visual support from the talking face. The speech-in-noise task involved the identification of a target word in a carrier sentence with a single competing speaker as a masker.

RESULTS

Children in the LLI group showed a deficit in speechreading when compared with their typically developing peers. Beyond the single-word level, this deficit became more apparent in older children. On the speech-in-noise task, a substantial benefit of visual cues was found regardless of age or group membership, although the LLI group showed an overall developmental delay in speech perception.

CONCLUSION

Although children with LLI were less accurate than their peers on the speechreading and speech-in noise-tasks, both groups were able to make equivalent use of visual cues to boost performance accuracy when listening in noise.

Processing of audiovisually congruent and incongruent speech in school-age children with a history of specific language impairment: a behavioral and event-related potentials study

Previous studies indicate that at least some aspects of audiovisual speech perception are impaired in children with specific language impairment (SLI). However, whether audiovisual processing difficulties are also present in older children with a history of this disorder is unknown. By combining electrophysiological and behavioral measures, we examined perception of both audiovisually congruent and audiovisually incongruent speech in school-age children with a history of SLI (H-SLI), their typically developing (TD) peers, and adults. In the first experiment, all participants watched videos of a talker articulating syllables 'ba', 'da', and 'ga' under three conditions - audiovisual (AV), auditory only (A), and visual only (V). The amplitude of the N1 (but not of the P2) event-related component elicited in the AV condition was significantly reduced compared to the N1 amplitude measured from the sum of the A and V conditions in all groups of participants. Because N1 attenuation to AV speech is thought to index the degree to which facial movements predict the onset of the auditory signal, our findings suggest that this aspect of audiovisual speech perception is mature by mid-childhood and is normal in the H-SLI children. In the second experiment, participants watched videos of audivisually incongruent syllables created to elicit the so-called McGurk illusion (with an auditory 'pa' dubbed onto a visual articulation of 'ka', and the expectant perception being that of 'ta' if audiovisual integration took place). As a group, H-SLI children were significantly more likely than either TD children or adults to hear the McGurk syllable as 'pa' (in agreement with its auditory component) than as 'ka' (in agreement with its visual component), suggesting that susceptibility to the McGurk illusion is reduced in at least some children with a history of SLI. Taken together, the results of the two experiments argue against global audiovisual integration impairment in children with a history of SLI and suggest that, when present, audiovisual integration difficulties in this population likely stem from a later (non-sensory) stage of processing.

Audiovisual integration of speech in a patient with Broca's Aphasia

Lesions to Broca's area cause aphasia characterized by a severe impairment of the ability to speak, with comparatively intact speech perception. However, some studies have found effects on speech perception under adverse listening conditions, indicating that Broca's area is also involved in speech perception. While these studies have focused on auditory speech perception other studies have shown that Broca's area is activated by visual speech perception. Furthermore, one preliminary report found that a patient with Broca's aphasia did not experience the McGurk illusion suggesting that an intact Broca's area is necessary for audiovisual integration of speech. Here we describe a patient with Broca's aphasia who experienced the McGurk illusion. This indicates that an intact Broca's area is not necessary for audiovisual integration of speech. The McGurk illusions this patient experienced were atypical, which could be due to Broca's area having a more subtle role in audiovisual integration of speech. The McGurk illusions of a control subject with Wernicke's aphasia were, however, also atypical. This indicates that the atypical McGurk illusions were due to deficits in speech processing that are not specific to Broca's aphasia.

Audiovisual integration for speech during mid-childhood: electrophysiological evidence

Previous studies have demonstrated that the presence of visual speech cues reduces the amplitude and latency of the N1 and P2 event-related potential (ERP) components elicited by speech stimuli. However, the developmental trajectory of this effect is not yet fully mapped. We examined ERP responses to auditory, visual, and audiovisual speech in two groups of school-age children (7-8-year-olds and 10-11-year-olds) and in adults. Audiovisual speech led to the attenuation of the N1 and P2 components in all groups of participants, suggesting that the neural mechanisms underlying these effects are functional by early school years. Additionally, while the reduction in N1 was largest over the right scalp, the P2 attenuation was largest over the left and midline scalp. The difference in the hemispheric distribution of the N1 and P2 attenuation supports the idea that these components index at least somewhat disparate neural processes within the context of audiovisual speech perception.

Tuning and disrupting the brain-modulating the McGurk illusion with electrical stimulation

In the so-called McGurk illusion, when the synchronized presentation of the visual stimulus /ga/ is paired with the auditory stimulus /ba/, people in general hear it as /da/. Multisensory integration processing underlying this illusion seems to occur within the Superior Temporal Sulcus (STS). Herein, we present evidence demonstrating that bilateral cathodal transcranial direct current stimulation (tDCS) of this area can decrease the McGurk illusion-type responses. Additionally, we show that the manipulation of this audio-visual integrated output occurs irrespective of the number of eye-fixations on the mouth of the speaker. Bilateral anodal tDCS of the Parietal Cortex also modulates the illusion, but in the opposite manner, inducing more illusion-type responses. This is the first demonstration of using non-invasive brain stimulation to modulate multisensory speech perception in an illusory context (i.e., both increasing and decreasing illusion-type responses to a verbal audio-visual integration task). These findings provide clear evidence that both the superior temporal and parietal areas contribute to multisensory integration processing related to speech perception. Specifically, STS seems fundamental for the temporal synchronization and integration of auditory and visual inputs. For its part, posterior parietal cortex (PPC) may adjust the arrival of incoming audio and visual information to STS thereby enhancing their interaction in this latter area.

Children with a history of SLI show reduced sensitivity to audiovisual temporal asynchrony: an ERP study

PURPOSE

The authors examined whether school-age children with a history of specific language impairment (H-SLI), their peers with typical development (TD), and adults differ in sensitivity to audiovisual temporal asynchrony and whether such difference stems from the sensory encoding of audiovisual information.

METHOD

Fifteen H-SLI children, 15 TD children, and 15 adults judged whether a flashed explosion-shaped figure and a 2-kHz pure tone occurred simultaneously. The stimuli were presented at 0-, 100-, 200-, 300-, 400-, and 500-ms temporal offsets. This task was combined with EEG recordings.

RESULTS

H-SLI children were profoundly less sensitive to temporal separations between auditory and visual modalities compared with their TD peers. Those H-SLI children who performed better at simultaneity judgment also had higher language aptitude. TD children were less accurate than adults, revealing a remarkably prolonged developmental course of the audiovisual temporal discrimination. Analysis of early event-related potential components suggested that poor sensory encoding was not a key factor in H-SLI children's reduced sensitivity to audiovisual asynchrony.

CONCLUSIONS

Audiovisual temporal discrimination is impaired in H-SLI children and is still immature during mid-childhood in TD children. The present findings highlight the need for further evaluation of the role of atypical audiovisual processing in the development of SLI.

Atypical audio-visual speech perception and McGurk effects in children with specific language impairment

Audiovisual speech perception of children with specific language impairment (SLI) and children with typical language development (TLD) was compared in two experiments using /aCa/ syllables presented in the context of a masking release paradigm. Children had to repeat syllables presented in auditory alone, visual alone (speechreading), audiovisual congruent and incongruent (McGurk) conditions. Stimuli were masked by either stationary (ST) or amplitude modulated (AM) noise. Although children with SLI were less accurate in auditory and audiovisual speech perception, they showed similar auditory masking release effect than children with TLD. Children with SLI also had less correct responses in speechreading than children with TLD, indicating impairment in phonemic processing of visual speech information. In response to McGurk stimuli, children with TLD showed more fusions in AM noise than in ST noise, a consequence of the auditory masking release effect and of the influence of visual information. Children with SLI did not show this effect systematically, suggesting they were less influenced by visual speech. However, when the visual cues were easily identified, the profile of responses to McGurk stimuli was similar in both groups, suggesting that children with SLI do not suffer from an impairment of audiovisual integration. An analysis of percent of information transmitted revealed a deficit in the children with SLI, particularly for the place of articulation feature. Taken together, the data support the hypothesis of an intact peripheral processing of auditory speech information, coupled with a supra modal deficit of phonemic categorization in children with SLI. Clinical implications are discussed.