Speech Processing in Autism Spectrum Disorder: An Integrative Review of Auditory Neurophysiology Findings

Author(s):  
Alexandra P. Key ◽  
Kathryn D'Ambrose Slaboch

Purpose Investigations into the nature of communication disorders in autistic individuals increasingly evaluate neural responses to speech stimuli. This integrative review aimed to consolidate the available data related to speech and language processing across levels of stimulus complexity (from single speech sounds to sentences) and to relate it to the current theories of autism. Method An electronic database search identified peer-reviewed articles using event-related potentials or magnetoencephalography to investigate auditory processing from single speech sounds to sentences in autistic children and adults varying in language and cognitive abilities. Results Atypical neural responses in autistic persons became more prominent with increasing stimulus and task complexity. Compared with their typically developing peers, autistic individuals demonstrated mostly intact sensory responses to single speech sounds, diminished spontaneous attentional orienting to spoken stimuli, specific difficulties with categorical speech sound discrimination, and reduced processing of semantic content. Atypical neural responses were more often observed in younger autistic participants and in those with concomitant language disorders. Conclusions The observed differences in neural responses to speech stimuli suggest that communication difficulties in autistic individuals are more consistent with the reduced social interest than the auditory dysfunction explanation. Current limitations and future directions for research are also discussed.

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250214
Author(s):  
Julien Plante-Hébert ◽  
Victor J. Boucher ◽  
Boutheina Jemel

Research has repeatedly shown that familiar and unfamiliar voices elicit different neural responses. But it has also been suggested that different neural correlates associate with the feeling of having heard a voice and knowing who the voice represents. The terminology used to designate these varying responses remains vague, creating a degree of confusion in the literature. Additionally, terms serving to designate tasks of voice discrimination, voice recognition, and speaker identification are often inconsistent creating further ambiguities. The present study used event-related potentials (ERPs) to clarify the difference between responses to 1) unknown voices, 2) trained-to-familiar voices as speech stimuli are repeatedly presented, and 3) intimately familiar voices. In an experiment, 13 participants listened to repeated utterances recorded from 12 speakers. Only one of the 12 voices was intimately familiar to a participant, whereas the remaining 11 voices were unfamiliar. The frequency of presentation of these 11 unfamiliar voices varied with only one being frequently presented (the trained-to-familiar voice). ERP analyses revealed different responses for intimately familiar and unfamiliar voices in two distinct time windows (P2 between 200–250 ms and a late positive component, LPC, between 450–850 ms post-onset) with late responses occurring only for intimately familiar voices. The LPC present sustained shifts, and short-time ERP components appear to reflect an early recognition stage. The trained voice equally elicited distinct responses, compared to rarely heard voices, but these occurred in a third time window (N250 between 300–350 ms post-onset). Overall, the timing of responses suggests that the processing of intimately familiar voices operates in two distinct steps of voice recognition, marked by a P2 on right centro-frontal sites, and speaker identification marked by an LPC component. The recognition of frequently heard voices entails an independent recognition process marked by a differential N250. Based on the present results and previous observations, it is proposed that there is a need to distinguish between processes of voice “recognition” and “identification”. The present study also specifies test conditions serving to reveal this distinction in neural responses, one of which bears on the length of speech stimuli given the late responses associated with voice identification.


2021 ◽  
Vol 15 ◽  
Author(s):  
Natalia Nudga ◽  
Josef Urbanec ◽  
Zuzana Oceláková ◽  
Jan Kremláček ◽  
Kateřina Chládková

Neural discrimination of auditory contrasts is usually studied via the mismatch negativity (MMN) component of the event-related potentials (ERPs). In the processing of speech contrasts, the magnitude of MMN is determined by both the acoustic as well as the phonological distance between stimuli. Also, the MMN can be modulated by the order in which the stimuli are presented, thus indexing perceptual asymmetries in speech sound processing. Here we assessed the MMN elicited by two types of phonological contrasts, namely vowel quality and vowel length, assuming that both will elicit a comparably strong MMN as both are phonemic in the listeners’ native language (Czech) and perceptually salient. Furthermore, we tested whether these phonemic contrasts are processed asymmetrically, and whether the asymmetries are acoustically or linguistically conditioned. The MMN elicited by the spectral change between /a/ and /ε/ was comparable to the MMN elicited by the durational change between /ε/ and /ε:/, suggesting that both types of contrasts are perceptually important for Czech listeners. The spectral change in vowels yielded an asymmetrical pattern manifested by a larger MMN response to the change from /ε/ to /a/ than from /a/ to /ε/. The lack of such an asymmetry in the MMN to the same spectral change in comparable non-speech stimuli spoke against an acoustically-based explanation, indicating that it may instead have been the phonological properties of the vowels that triggered the asymmetry. The potential phonological origins of the asymmetry are discussed within the featurally underspecified lexicon (FUL) framework, and conclusions are drawn about the perceptual relevance of the place and height features for the Czech /ε/-/a/ contrast.


2005 ◽  
Vol 16 (01) ◽  
pp. 042-053 ◽  
Author(s):  
A.J. Beynon ◽  
A.F.M. Snik ◽  
D.F. Stegeman ◽  
P. van den Broek

Cortical potentials evoked with speech stimuli were investigated in ten experienced cochlear implant (CI, type Nucleus 24M) users using three different speech-coding strategies and two different speech contrasts, one vowel (/i/-/a/) and one consonant (/ba/-/da/) contrast. On average, results showed that, compared to subjects with normal hearing, P300 amplitudes were smaller; however, most latencies were within the normal range. Next, individual P300 measures in response to the two speech contrasts were compared to behavioral discrimination scores. Significant within-subject differences in P300 amplitudes and latencies were found for the three speech coding strategies. These differences were in agreement with the behavioral, strategy-dependent discrimination of the speech contrasts.


2020 ◽  
Author(s):  
Patrick Dwyer ◽  
Xiaodong Wang ◽  
Rosanna De Meo-Monteil ◽  
Fushing Hsieh ◽  
Clifford D. Saron ◽  
...  

Abstract Background: Autistic individuals exhibit atypical patterns of sensory processing that are known to be related to quality of life, but which are also highly heterogeneous. Previous investigations of this heterogeneity have ordinarily used questionnaires and have rarely investigated sensory processing in Typical Development (TD) alongside Autism Spectrum Development (ASD). Methods: The present study used hierarchical clustering in a large sample to identify subgroups of young autistic and typically-developing children based the normalized global field power (GFP) of their event-related potentials (ERPs) to auditory stimuli of four different loudness intensities (50, 60, 70, 80 dB SPL): that is, based on an index of the relative strengths of their neural responses across these loudness conditions. Results: Four clusters of participants were defined. Normalized GFP responses to sounds of different intensities differed strongly across clusters. There was considerable overlap in cluster assignments of autistic and typically-developing participants, but autistic participants were more likely to display a pattern of relatively linear increases in response strength accompanied by a disproportionately strong response to 70 dB stimuli. Autistic participants displaying this pattern trended towards obtaining higher scores on assessments of cognitive abilities. There was also a trend for typically-developing participants to disproportionately fall into a cluster characterized by disproportionately/nonlinearly strong 60 dB responses. Greater auditory distractibility was reported among autistic participants in a cluster characterized by disproportionately strong responses to the loudest (80 dB) sounds, and furthermore, relatively strong responses to loud sounds were correlated with both auditory distractibility and noise distress. This appears to provide evidence of coinciding behavioural and neural sensory atypicalities. Limitations : Replication may be needed to verify exploratory results. This analysis may ignore some variability related to classical ERP latencies and topographies. The sensory questionnaire employed was not specifically designed for use in autism. Variability in sensory responses unrelated to loudness is ignored, leaving much room for additional research. Conclusions: Taken together, these data demonstrate the broader benefits of using electrophysiology to explore individual differences. They illuminate different neural response patterns and suggest relationships between sensory neural responses and sensory behaviours, cognitive abilities, and autism diagnostic status.


2020 ◽  
Author(s):  
Patrick Dwyer ◽  
Xiaodong Wang ◽  
Rosanna De Meo-Monteil ◽  
Fushing Hsieh ◽  
Clifford D. Saron ◽  
...  

Abstract Background: Autistic individuals exhibit atypical patterns of sensory processing that are known to be related to quality of life, but which are also highly heterogeneous. Previous investigations of this heterogeneity have ordinarily used questionnaires and have rarely investigated sensory processing in Typical Development (TD) alongside Autism Spectrum Development (ASD). Methods: The present study used hierarchical clustering in a large sample to identify subgroups of young autistic and typically-developing children based the normalized global field power (GFP) of their event-related potentials (ERPs) to auditory stimuli of four different loudness intensities (50, 60, 70, 80 dB SPL): that is, based on an index of the relative strengths of their neural responses across these loudness conditions. Results: Four clusters of participants were defined. Normalized GFP responses to sounds of different intensities differed strongly across clusters. There was considerable overlap in cluster assignments of autistic and typically-developing participants, but autistic participants were more likely to display a pattern of relatively linear increases in response strength accompanied by a disproportionately strong response to 70 dB stimuli. Autistic participants displaying this pattern trended towards obtaining higher scores on assessments of cognitive abilities. There was also a trend for typically-developing participants to disproportionately fall into a cluster characterized by disproportionately/nonlinearly strong 60 dB responses. Greater auditory distractibility was reported among autistic participants in a cluster characterized by disproportionately strong responses to the loudest (80 dB) sounds, and furthermore, relatively strong responses to loud sounds were correlated with both auditory distractibility and noise distress. This appears to provide evidence of coinciding behavioural and neural sensory atypicalities. Limitations : Replication may be needed to verify exploratory results. This analysis may ignore some variability related to classical ERP latencies and topographies. The sensory questionnaire employed was not specifically designed for use in autism. Variability in sensory responses unrelated to loudness is ignored, leaving much room for additional research. Conclusions: Taken together, these data demonstrate the broader benefits of using electrophysiology to explore individual differences. They illuminate different neural response patterns and suggest relationships between sensory neural responses and sensory behaviours, cognitive abilities, and autism diagnostic status.


2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Jona Sassenhagen ◽  
Ryan Blything ◽  
Elena V. M. Lieven ◽  
Ben Ambridge

How are verb-argument structure preferences acquired? Children typically receive very little negative evidence, raising the question of how they come to understand the restrictions on grammatical constructions. Statistical learning theories propose stochastic patterns in the input contain sufficient clues. For example, if a verb is very common, but never observed in transitive constructions, this would indicate that transitive usage of that verb is illegal. Ambridge et al. (2008) have shown that in offline grammaticality judgements of intransitive verbs used in transitive constructions, low-frequency verbs elicit higher acceptability ratings than high-frequency verbs, as predicted if relative frequency is a cue during statistical learning. Here, we investigate if the same pattern also emerges in on-line processing of English sentences. EEG was recorded while healthy adults listened to sentences featuring transitive uses of semantically matched verb pairs of differing frequencies. We replicate the finding of higher acceptabilities of transitive uses of low- vs. high-frequency intransitive verbs. Event-Related Potentials indicate a similar result: early electrophysiological signals distinguish between misuse of high- vs low-frequency verbs. This indicates online processing shows a similar sensitivity to frequency as off-line judgements, consistent with a parser that reflects an original acquisition of grammatical constructions via statistical cues. However, the nature of the observed neural responses was not of the expected, or an easily interpretable, form, motivating further work into neural correlates of online processing of syntactic constructions.


Author(s):  
Luodi Yu ◽  
Jiajing Zeng ◽  
Suiping Wang ◽  
Yang Zhang

Purpose This study aimed to examine whether abstract knowledge of word-level linguistic prosody is independent of or integrated with phonetic knowledge. Method Event-related potential (ERP) responses were measured from 18 adult listeners while they listened to native and nonnative word-level prosody in speech and in nonspeech. The prosodic phonology (speech) conditions included disyllabic pseudowords spoken in Chinese and in English matched for syllabic structure, duration, and intensity. The prosodic acoustic (nonspeech) conditions were hummed versions of the speech stimuli, which eliminated the phonetic content while preserving the acoustic prosodic features. Results We observed language-specific effects on the ERP that native stimuli elicited larger late negative response (LNR) amplitude than nonnative stimuli in the prosodic phonology conditions. However, no such effect was observed in the phoneme-free prosodic acoustic control conditions. Conclusions The results support the integration view that word-level linguistic prosody likely relies on the phonetic content where the acoustic cues embedded in. It remains to be examined whether the LNR may serve as a neural signature for language-specific processing of prosodic phonology beyond auditory processing of the critical acoustic cues at the suprasyllabic level.


CoDAS ◽  
2021 ◽  
Vol 33 (2) ◽  
Author(s):  
Mariana Keiko Kamita ◽  
Liliane Aparecida Fagundes Silva ◽  
Carla Gentile Matas

RESUMO Objetivo Identificar e analisar quais são os achados característicos dos Potenciais Evocados Auditivos Corticais (PEAC) em crianças e/ou adolescentes com Transtorno do Espectro do Autismo (TEA) em comparação do desenvolvimento típico, por meio de uma revisão sistemática da literatura. Estratégia de pesquisa Após formulação da pergunta de pesquisa, foi realizada uma revisão da literatura em sete bases de dados (Web of Science, Pubmed, Cochrane Library, Lilacs, Scielo, Science Direct, e Google acadêmico), com os seguintes descritores: transtorno do espectro autista (autism spectrum disorder), transtorno autístico (autistic disorder), potenciais evocados auditivos (evoked potentials, auditory), potencial evocado P300 (event related potentials, P300) e criança (child). A presente revisão foi cadastrada no Próspero, sob número 118751. Critérios de seleção Foram selecionados estudos publicados na integra, sem limitação de idioma, entre 2007 e 2019. Análise dos dados: Foram analisadas as características de latência e amplitude dos componentes P1, N1, P2, N2 e P3 presentes nos PEAC. Resultados Foram localizados 193 estudos; contudo 15 estudos contemplaram os critérios de inclusão. Embora não tenha sido possível identificar um padrão de resposta para os componentes P1, N1, P2, N2 e P3, os resultados da maioria dos estudos demonstraram que indivíduos com TEA podem apresentar diminuição de amplitude e aumento de latência do componente P3. Conclusão Indivíduos com TEA podem apresentar respostas diversas para os componentes dos PEAC, sendo que a diminuição de amplitude e aumento de latência do componente P3 foram as características mais comuns.


2020 ◽  
Author(s):  
Katja Junttila ◽  
Anna-Riikka Smolander ◽  
Reima Karhila ◽  
Anastasia Giannakopoulou ◽  
Maria Uther ◽  
...  

Learning is increasingly assisted by technology. Digital games may be useful for learning, especially in children. However, more research is needed to understand the factors that induce gaming benefits to cognition. In this study, we investigated the effectiveness of digital game-based learning approach in children by comparing the learning of foreign speech sounds and words in a digital game or a non-game digital application with equal amount of exposure and practice. To evaluate gaming-induced plastic changes in the brain function, we used the mismatch negativity (MMN) brain response that reflects the activation of long-term memory representations for speech sounds and words. We recorded auditory event-related potentials (ERPs) from 37 school-aged Finnish-speaking children before and after playing the “Say it again, kid!” (SIAK) language-learning game where they explored game boards, produced English words aloud, and got stars as feedback from an automatic speech recognizer to proceed in the game. The learning of foreign speech sounds and words was compared in two conditions embedded in the game: a game condition and a non-game condition with the same speech production task but lacking visual game elements and feedback. The MMN amplitude increased between the pre-measurement and the post-measurement for the word trained with the game but not for the word trained with the non-game condition, suggesting that the gaming intervention enhanced learning more than the non-game intervention. The results indicate that digital game-based learning can be beneficial for children’s language learning and that gaming elements per se, not just practise time, support learning.


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