Visual Speech Stimuli Research Articles

Neural correlates of audiovisual speech synchrony perception and its relationship with autistic traits.

The anterior insula (AI) has the central role in coordinating attention and integrating information from multiple sensory modalities. AI dysfunction may contribute to both sensory and social impairments in autism spectrum disorder (ASD). Little is known regarding the brain mechanisms that guide multisensory integration, and how such neural activity might be affected by autistic-like symptoms in the general population. In this study, 72 healthy young adults performed an audiovisual speech synchrony judgment (SJ) task during fMRI scanning. We aimed to investigate the SJ-related brain activations and connectivity, with a focus on the AI. Compared with synchronous speech, asynchrony perception triggered stronger activations in the bilateral AI, and other frontal-cingulate-parietal regions. In contrast, synchronous perception resulted in greater involvement of the primary auditory and visual areas, indicating multisensory validation and fusion. Moreover, the AI demonstrated a stronger connection with the anterior cingulate gyrus (ACC) in the audiovisual asynchronous (vs. synchronous) condition. To facilitate asynchrony detection, the AI may integrate auditory and visual speech stimuli, and generate a control signal to the ACC that further supports conflict-resolving and response selection. Correlation analysis, however, suggested that audiovisual synchrony perception and its related AI activation and connectivity did not significantly vary with different levels of autistic traits. These findings provide novel evidence for the neural mechanisms underlying multisensory temporal processing in healthy people. Future research should examine whether such findings would be extended to ASD patients.

Cross-modal functional connectivity supports speech understanding in cochlear implant users.

Sensory deprivation can lead to cross-modal cortical changes, whereby sensory brain regions deprived of input may be recruited to perform atypical function. Enhanced cross-modal responses to visual stimuli observed in auditory cortex of postlingually deaf cochlear implant (CI) users are hypothesized to reflect increased activation of cortical language regions, but it is unclear if this cross-modal activity is "adaptive" or "mal-adaptive" for speech understanding. To determine if increased activation of language regions is correlated with better speech understanding in CI users, we assessed task-related activation and functional connectivity of auditory and visual cortices to auditory and visual speech and non-speech stimuli in CI users (n = 14) and normal-hearing listeners (n = 17) and used functional near-infrared spectroscopy to measure hemodynamic responses. We used visually presented speech and non-speech to investigate neural processes related to linguistic content and observed that CI users show beneficial cross-modal effects. Specifically, an increase in connectivity between the left auditory and visual cortices-presumed primary sites of cortical language processing-was positively correlated with CI users' abilities to understand speech in background noise. Cross-modal activity in auditory cortex of postlingually deaf CI users may reflect adaptive activity of a distributed, multimodal speech network, recruited to enhance speech understanding.

Contralateral dominance to speech in the adult auditory cortex immediately after cochlear implantation

SummarySensory deprivation causes structural and functional changes in the human brain. Cochlear implantation delivers immediate reintroduction of auditory sensory information. Previous reports have indicated that over a year is required for the brain to reestablish canonical cortical processing patterns after the reintroduction of auditory stimulation. We utilized functional near-infrared spectroscopy (fNIRS) to investigate brain activity to natural speech stimuli directly after cochlear implantation. We presented 12 cochlear implant recipients, who each had a minimum of 12 months of auditory deprivation, with unilateral auditory- and visual-speech stimuli. Regardless of the side of implantation, canonical responses were elicited primarily on the contralateral side of stimulation as early as 1 h after device activation. These data indicate that auditory pathway connections are sustained during periods of sensory deprivation in adults, and that typical cortical lateralization is observed immediately following the reintroduction of auditory sensory input.

Adults and children predict in complex and variable referential contexts

ABSTRACT Prior research suggests that prediction supports language processing and learning. However, the ecological validity of such findings is unclear because experiments usually include constrained stimuli. While theoretically suggestive, previous conclusions will be largely irrelevant if listeners cannot generate predictions in response to complex and variable perceptual input. Taking a step toward addressing this limitation, three eye-tracking experiments evaluated how adults (N = 72) and 4- and 5-year-old children (N = 72) generated predictions in contexts with complex visual stimuli (Experiment 1), variable speech stimuli (Experiment 2), and both concurrently (Experiment 3). Results indicated that listeners generated predictions in contexts with complex visual stimuli or variable speech stimuli. When both were more naturalistic, listeners used informative verbs to generate predictions, but not adjectives or number markings. This investigation provides a test for theories claiming that prediction is a central learning mechanism, and calls for further evaluations of prediction in naturalistic settings.

Emotional state dependence facilitates automatic imitation of visual speech.

Observing someone speak automatically triggers cognitive and neural mechanisms required to produce speech, a phenomenon known as automatic imitation. Automatic imitation of speech can be measured using the Stimulus Response Compatibility (SRC) paradigm that shows facilitated response times (RTs) when responding to a prompt (e.g., say aa) in the presence of a congruent distracter (a video of someone saying aa), compared with responding in the presence of an incongruent distracter (a video of someone saying oo). Current models of the relation between emotion and cognitive control suggest that automatic imitation can be modulated by varying the stimulus-driven task aspects, that is, the distracter's emotional valence. It is unclear how the emotional state of the observer affects automatic imitation. The current study explored independent effects of emotional valence of the distracter (Stimulus-driven Dependence) and the observer's emotional state (State Dependence) on automatic imitation of speech. Participants completed an SRC paradigm for visual speech stimuli. They produced a prompt superimposed over a neutral or emotional (happy or angry) distracter video. State Dependence was manipulated by asking participants to speak the prompt in a neutral or emotional (happy or angry) voice. Automatic imitation was facilitated for emotional prompts, but not for emotional distracters, thus implying a facilitating effect of State Dependence. The results are interpreted in the context of theories of automatic imitation and cognitive control, and we suggest that models of automatic imitation are to be modified to accommodate for state-dependent and stimulus-driven dependent effects.

Auditory–visual integration during nonconscious perception

Our study proposes a test of a key assumption of the most prominent model of consciousness – the global workspace (GWS) model (e.g., Baars, 2002, 2005, 2007; Dehaene & Naccache, 2001; Mudrik, Faivre, & Koch, 2014). This assumption is that multimodal integration requires consciousness; however, few studies have explicitly tested if integration can occur between nonconscious information from different modalities. The proposed study examined whether a classic indicator of multimodal integration – the McGurk effect – can be elicited with subliminal auditory–visual speech stimuli. We used a masked speech priming paradigm developed by Kouider and Dupoux (2005) in conjunction with continuous flash suppression (CFS; Tsuchiya & Koch, 2005), a binocular rivalry technique for presenting video stimuli subliminally. Applying these techniques together, we carried out two experiments in which participants categorised auditory syllable targets which were preceded by subliminal auditory–visual (AV) speech primes. Subliminal AV primes were either illusion-inducing (McGurk) or illusion-neutral (Incongruent) combinations of speech stimuli. In Experiment 1, the categorisation of the syllable target (“pa”) was facilitated by the same syllable prime when it was part of a McGurk combination (auditory “pa” and visual “ka”) but not when part of an Incongruent combination (auditory “pa” and visual “wa”). This dependency on specific AV combinations indicated a nonconscious AV interaction. Experiment 2 presented a different syllable target (“ta”) which matched the predicted illusory outcome of the McGurk combination – here, both the McGurk combination (auditory “pa” and visual “ka”) and the Incongruent combination (auditory “ta” and visual “ka”) failed to facilitate target categorisation. The combined results of both Experiments demonstrate a type of nonconscious multimodal interaction that is distinct from integration – it allows unimodal information that is compatible for integration (i.e., McGurk combinations) to persist and influence later processes, but does not actually combine and alter that information. As the GWS model does not account for non-integrative multimodal interactions, this places some pressure on such models of consciousness.

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.

Validating a Method to Assess Lipreading, Audiovisual Gain, and Integration During Speech Reception With Cochlear-Implanted and Normal-Hearing Subjects Using a Talking Head.

Watching a talker's mouth is beneficial for speech reception (SR) in many communication settings, especially in noise and when hearing is impaired. Measures for audiovisual (AV) SR can be valuable in the framework of diagnosing or treating hearing disorders. This study addresses the lack of standardized methods in many languages for assessing lipreading, AV gain, and integration. A new method is validated that supplements a German speech audiometric test with visualizations of the synthetic articulation of an avatar that was used, for it is feasible to lip-sync auditory speech in a highly standardized way. Three hypotheses were formed according to the literature on AV SR that used live or filmed talkers. It was tested whether respective effects could be reproduced with synthetic articulation: (1) cochlear implant (CI) users have a higher visual-only SR than normal-hearing (NH) individuals, and younger individuals obtain higher lipreading scores than older persons. (2) Both CI and NH gain from presenting AV over unimodal (auditory or visual) sentences in noise. (3) Both CI and NH listeners efficiently integrate complementary auditory and visual speech features. In a controlled, cross-sectional study with 14 experienced CI users (mean age 47.4) and 14 NH individuals (mean age 46.3, similar broad age distribution), lipreading, AV gain, and integration of a German matrix sentence test were assessed. Visual speech stimuli were synthesized by the articulation of the Talking Head system "MASSY" (Modular Audiovisual Speech Synthesizer), which displayed standardized articulation with respect to the visibility of German phones. In line with the hypotheses and previous literature, CI users had a higher mean visual-only SR than NH individuals (CI, 38%; NH, 12%; p < 0.001). Age was correlated with lipreading such that within each group, younger individuals obtained higher visual-only scores than older persons (rCI = -0.54; p = 0.046; rNH = -0.78; p < 0.001). Both CI and NH benefitted by AV over unimodal speech as indexed by calculations of the measures visual enhancement and auditory enhancement (each p < 0.001). Both groups efficiently integrated complementary auditory and visual speech features as indexed by calculations of the measure integration enhancement (each p < 0.005). Given the good agreement between results from literature and the outcome of supplementing an existing validated auditory test with synthetic visual cues, the introduced method can be considered an interesting candidate for clinical and scientific applications to assess measures important for AV SR in a standardized manner. This could be beneficial for optimizing the diagnosis and treatment of individual listening and communication disorders, such as cochlear implantation.

Audio-visual speech processing in age-related hearing loss: Stronger integration and increased frontal lobe recruitment

Hearing loss is associated with difficulties in understanding speech, especially under adverse listening conditions. In these situations, seeing the speaker improves speech intelligibility in hearing-impaired participants. On the neuronal level, previous research has shown cross-modal plastic reorganization in the auditory cortex following hearing loss leading to altered processing of auditory, visual and audio-visual information. However, how reduced auditory input effects audio-visual speech perception in hearing-impaired subjects is largely unknown. We here investigated the impact of mild to moderate age-related hearing loss on processing audio-visual speech using functional magnetic resonance imaging. Normal-hearing and hearing-impaired participants performed two audio-visual speech integration tasks: a sentence detection task inside the scanner and the McGurk illusion outside the scanner. Both tasks consisted of congruent and incongruent audio-visual conditions, as well as auditory-only and visual-only conditions. We found a significantly stronger McGurk illusion in the hearing-impaired participants, which indicates stronger audio-visual integration. Neurally, hearing loss was associated with an increased recruitment of frontal brain areas when processing incongruent audio-visual, auditory and also visual speech stimuli, which may reflect the increased effort to perform the task. Hearing loss modulated both the audio-visual integration strength measured with the McGurk illusion and brain activation in frontal areas in the sentence task, showing stronger integration and higher brain activation with increasing hearing loss. Incongruent compared to congruent audio-visual speech revealed an opposite brain activation pattern in left ventral postcentral gyrus in both groups, with higher activation in hearing-impaired participants in the incongruent condition. Our results indicate that already mild to moderate hearing loss impacts audio-visual speech processing accompanied by changes in brain activation particularly involving frontal areas. These changes are modulated by the extent of hearing loss.

Response Errors in Females' and Males' Sentence Lipreading Necessitate Structurally Different Models for Predicting Lipreading Accuracy.

Lipreaders recognize words with phonetically impoverished stimuli, an ability that is generally poor in normal-hearing adults. Individual sentence lipreading trials from 341 young adults were modeled to predict words and phonemes correct in terms of measures of phoneme response dissimilarity (PRD), number of inserted incorrect response phonemes, lipreader gender, and a measure of speech perception in noise. Interactions with lipreaders' gender necessitated structurally different models of males' and females' lipreading. Overall, female lipreaders are more accurate, their ability to recognize words with impoverished or degraded input is consistent across visual and auditory modalities, and they amplify their correct responding through top-down insertion of text. Males' responses suggest that individuals with poorer auditory speech perception in noise amplify their responses by shifting towards including text in their response that is more perceptually discrepant from the stimulus. Attention to gender differences merits attention in future studies that use visual speech stimuli.

Electrophysiological evidence for a self-processing advantage during audiovisual speech integration.

Previous electrophysiological studies have provided strong evidence for early multisensory integrative mechanisms during audiovisual speech perception. From these studies, one unanswered issue is whether hearing our own voice and seeing our own articulatory gestures facilitate speech perception, possibly through a better processing and integration of sensory inputs with our own sensory-motor knowledge. The present EEG study examined the impact of self-knowledge during the perception of auditory (A), visual (V) and audiovisual (AV) speech stimuli that were previously recorded from the participant or from a speaker he/she had never met. Audiovisual interactions were estimated by comparing N1 and P2 auditory evoked potentials during the bimodal condition (AV) with the sum of those observed in the unimodal conditions (A+V). In line with previous EEG studies, our results revealed an amplitude decrease of P2 auditory evoked potentials in AV compared to A+V conditions. Crucially, a temporal facilitation of N1 responses was observed during the visual perception of self speech movements compared to those of another speaker. This facilitation was negatively correlated with the saliency of visual stimuli. These results provide evidence for a temporal facilitation of the integration of auditory and visual speech signals when the visual situation involves our own speech gestures.

Auditory, Visual and Audiovisual Speech Processing Streams in Superior Temporal Sulcus.

The human superior temporal sulcus (STS) is responsive to visual and auditory information, including sounds and facial cues during speech recognition. We investigated the functional organization of STS with respect to modality-specific and multimodal speech representations. Twenty younger adult participants were instructed to perform an oddball detection task and were presented with auditory, visual, and audiovisual speech stimuli, as well as auditory and visual nonspeech control stimuli in a block fMRI design. Consistent with a hypothesized anterior-posterior processing gradient in STS, auditory, visual and audiovisual stimuli produced the largest BOLD effects in anterior, posterior and middle STS (mSTS), respectively, based on whole-brain, linear mixed effects and principal component analyses. Notably, the mSTS exhibited preferential responses to multisensory stimulation, as well as speech compared to nonspeech. Within the mid-posterior and mSTS regions, response preferences changed gradually from visual, to multisensory, to auditory moving posterior to anterior. Post hoc analysis of visual regions in the posterior STS revealed that a single subregion bordering the mSTS was insensitive to differences in low-level motion kinematics yet distinguished between visual speech and nonspeech based on multi-voxel activation patterns. These results suggest that auditory and visual speech representations are elaborated gradually within anterior and posterior processing streams, respectively, and may be integrated within the mSTS, which is sensitive to more abstract speech information within and across presentation modalities. The spatial organization of STS is consistent with processing streams that are hypothesized to synthesize perceptual speech representations from sensory signals that provide convergent information from visual and auditory modalities.

Multisensory speech perception in autism spectrum disorder: From phoneme to whole-word perception.

Speech perception in noisy environments is boosted when a listener can see the speaker's mouth and integrate the auditory and visual speech information. Autistic children have a diminished capacity to integrate sensory information across modalities, which contributes to core symptoms of autism, such as impairments in social communication. We investigated the abilities of autistic and typically-developing (TD) children to integrate auditory and visual speech stimuli in various signal-to-noise ratios (SNR). Measurements of both whole-word and phoneme recognition were recorded. At the level of whole-word recognition, autistic children exhibited reduced performance in both the auditory and audiovisual modalities. Importantly, autistic children showed reduced behavioral benefit from multisensory integration with whole-word recognition, specifically at low SNRs. At the level of phoneme recognition, autistic children exhibited reduced performance relative to their TD peers in auditory, visual, and audiovisual modalities. However, and in contrast to their performance at the level of whole-word recognition, both autistic and TD children showed benefits from multisensory integration for phoneme recognition. In accordance with the principle of inverse effectiveness, both groups exhibited greater benefit at low SNRs relative to high SNRs. Thus, while autistic children showed typical multisensory benefits during phoneme recognition, these benefits did not translate to typical multisensory benefit of whole-word recognition in noisy environments. We hypothesize that sensory impairments in autistic children raise the SNR threshold needed to extract meaningful information from a given sensory input, resulting in subsequent failure to exhibit behavioral benefits from additional sensory information at the level of whole-word recognition. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1280-1290. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

The temporal binding window for audiovisual speech: Children are like little adults

During a typical communication exchange, both auditory and visual cues contribute to speech comprehension. The influence of vision on speech perception can be measured behaviorally using a task where incongruent auditory and visual speech stimuli are paired to induce perception of a novel token reflective of multisensory integration (i.e., the McGurk effect). This effect is temporally constrained in adults, with illusion perception decreasing as the temporal offset between the auditory and visual stimuli increases. Here, we used the McGurk effect to investigate the development of the temporal characteristics of audiovisual speech binding in 7–24 year-olds. Surprisingly, results indicated that although older participants perceived the McGurk illusion more frequently, no age-dependent change in the temporal boundaries of audiovisual speech binding was observed.

Temporal Cortex Activation to Audiovisual Speech in Normal-Hearing and Cochlear Implant Users Measured with Functional Near-Infrared Spectroscopy.

Background: Speech understanding may rely not only on auditory, but also on visual information. Non-invasive functional neuroimaging techniques can expose the neural processes underlying the integration of multisensory processes required for speech understanding in humans. Nevertheless, noise (from functional MRI, fMRI) limits the usefulness in auditory experiments, and electromagnetic artifacts caused by electronic implants worn by subjects can severely distort the scans (EEG, fMRI). Therefore, we assessed audio-visual activation of temporal cortex with a silent, optical neuroimaging technique: functional near-infrared spectroscopy (fNIRS).Methods: We studied temporal cortical activation as represented by concentration changes of oxy- and deoxy-hemoglobin in four, easy-to-apply fNIRS optical channels of 33 normal-hearing adult subjects and five post-lingually deaf cochlear implant (CI) users in response to supra-threshold unisensory auditory and visual, as well as to congruent auditory-visual speech stimuli.Results: Activation effects were not visible from single fNIRS channels. However, by discounting physiological noise through reference channel subtraction (RCS), auditory, visual and audiovisual (AV) speech stimuli evoked concentration changes for all sensory modalities in both cohorts (p < 0.001). Auditory stimulation evoked larger concentration changes than visual stimuli (p < 0.001). A saturation effect was observed for the AV condition.Conclusions: Physiological, systemic noise can be removed from fNIRS signals by RCS. The observed multisensory enhancement of an auditory cortical channel can be plausibly described by a simple addition of the auditory and visual signals with saturation.

Facial speech gestures: the relation between visual speech processing, phonological awareness, and developmental dyslexia in 10-year-olds.

Successful communication in everyday life crucially involves the processing of auditory and visual components of speech. Viewing our interlocutor and processing visual components of speech facilitates speech processing by triggering auditory processing. Auditory phoneme processing, analyzed by event-related brain potentials (ERP), has been shown to be associated with impairments in reading and spelling (i.e. developmental dyslexia), but visual aspects of phoneme processing have not been investigated in individuals with such deficits. The present study analyzed the passive visual Mismatch Response (vMMR) in school children with and without developmental dyslexia in response to video-recorded mouth movements pronouncing syllables silently. Our results reveal that both groups of children showed processing of visual speech stimuli, but with different scalp distribution. Children without developmental dyslexia showed a vMMR with typical posterior distribution. In contrast, children with developmental dyslexia showed a vMMR with anterior distribution, which was even more pronounced in children with severe phonological deficits and very low spelling abilities. As anterior scalp distributions are typically reported for auditory speech processing, the anterior vMMR of children with developmental dyslexia might suggest an attempt to anticipate potentially upcoming auditory speech information in order to support phonological processing, which has been shown to be deficient in children with developmental dyslexia.

Multisensory and sensorimotor interactions in speech perception.

This research topic presents speech as a natural, well-learned, multisensory communication signal, processed by multiple mechanisms. Reflecting the general status of the field, most articles focus on audiovisual speech perception and many utilize the McGurk effect, which arises when discrepant visual and auditory speech stimuli are presented (McGurk and MacDonald, 1976). Tiippana (2014) argues that the McGurk effect can be used as a proxy for multisensory integration provided it is not interpreted too narrowly.

Visual speech gestures modulate efferent auditory system.

Visual and auditory systems interact at both cortical and subcortical levels. Studies suggest a highly context-specific cross-modal modulation of the auditory system by the visual system. The present study builds on this work by sampling data from 17 young healthy adults to test whether visual speech stimuli evoke different responses in the auditory efferent system compared to visual non-speech stimuli. The descending cortical influences on medial olivocochlear (MOC) activity were indirectly assessed by examining the effects of contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) at 1, 2, 3 and 4 kHz under three conditions: (a) in the absence of any contralateral noise (Baseline), (b) contralateral noise + observing facial speech gestures related to productions of vowels /a/ and /u/ and (c) contralateral noise + observing facial non-speech gestures related to smiling and frowning. The results are based on 7 individuals whose data met strict recording criteria and indicated a significant difference in TEOAE suppression between observing speech gestures relative to the non-speech gestures, but only at the 1 kHz frequency. These results suggest that observing a speech gesture compared to a non-speech gesture may trigger a difference in MOC activity, possibly to enhance peripheral neural encoding. If such findings can be reproduced in future research, sensory perception models and theories positing the downstream convergence of unisensory streams of information in the cortex may need to be revised.

Neural pathways for visual speech perception.

This paper examines the questions, what levels of speech can be perceived visually, and how is visual speech represented by the brain? Review of the literature leads to the conclusions that every level of psycholinguistic speech structure (i.e., phonetic features, phonemes, syllables, words, and prosody) can be perceived visually, although individuals differ in their abilities to do so; and that there are visual modality-specific representations of speech qua speech in higher-level vision brain areas. That is, the visual system represents the modal patterns of visual speech. The suggestion that the auditory speech pathway receives and represents visual speech is examined in light of neuroimaging evidence on the auditory speech pathways. We outline the generally agreed-upon organization of the visual ventral and dorsal pathways and examine several types of visual processing that might be related to speech through those pathways, specifically, face and body, orthography, and sign language processing. In this context, we examine the visual speech processing literature, which reveals widespread diverse patterns of activity in posterior temporal cortices in response to visual speech stimuli. We outline a model of the visual and auditory speech pathways and make several suggestions: (1) The visual perception of speech relies on visual pathway representations of speech qua speech. (2) A proposed site of these representations, the temporal visual speech area (TVSA) has been demonstrated in posterior temporal cortex, ventral and posterior to multisensory posterior superior temporal sulcus (pSTS). (3) Given that visual speech has dynamic and configural features, its representations in feedforward visual pathways are expected to integrate these features, possibly in TVSA.

Cross-modal matching of audio-visual German and French fluent speech in infancy.

The present study examined when and how the ability to cross-modally match audio-visual fluent speech develops in 4.5-, 6- and 12-month-old German-learning infants. In Experiment 1, 4.5- and 6-month-old infants’ audio-visual matching ability of native (German) and non-native (French) fluent speech was assessed by presenting auditory and visual speech information sequentially, that is, in the absence of temporal synchrony cues. The results showed that 4.5-month-old infants were capable of matching native as well as non-native audio and visual speech stimuli, whereas 6-month-olds perceived the audio-visual correspondence of native language stimuli only. This suggests that intersensory matching narrows for fluent speech between 4.5 and 6 months of age. In Experiment 2, auditory and visual speech information was presented simultaneously, therefore, providing temporal synchrony cues. Here, 6-month-olds were found to match native as well as non-native speech indicating facilitation of temporal synchrony cues on the intersensory perception of non-native fluent speech. Intriguingly, despite the fact that audio and visual stimuli cohered temporally, 12-month-olds matched the non-native language only. Results were discussed with regard to multisensory perceptual narrowing during the first year of life.