The Relationship between Form and Function Level Receptive Prosodic Abilities in Autism

Perception and adaptation of receptive prosody in autistic adolescents

A fundamental aspect of language processing is inferring others' minds from subtle variations in speech. The same word or sentence can often convey different meanings depending on its tempo, timing, and intonation-features often referred to as prosody. Although autistic children and adults are known to experience difficulty in making such inferences, the science remains unclear as to why. We hypothesize that detail-oriented perception in autism may interfere with the inference process if it lacks the adaptivity required to cope with the variability ubiquitous in human speech. Using a novel prosodic continuum that shifts the sentence meaning gradiently from a statement (e.g., "It's raining") to a question (e.g., "It's raining?"), we have investigated the perception and adaptation of receptive prosody in autistic adolescents and two groups of non-autistic controls. Autistic adolescents showed attenuated adaptivity in categorizing prosody, whereas they were equivalent to controls in terms of discrimination accuracy. Combined with recent findings in segmental (e.g., phoneme) recognition, the current results provide the basis for an emerging research framework for attenuated flexibility and reduced influence of contextual feedback as a possible source of deficits that hinder linguistic and social communication in autism.

Acoustic and Semantic Processing of Auditory Scenes in Children with Autism Spectrum Disorders

PURPOSE

Processing real-world sounds requires acoustic and higher-order semantic information. We tested the theory that individuals with autism spectrum disorder (ASD) show enhanced processing of acoustic features and impaired processing of semantic information.

METHODS

We used a change deafness task that required detection of speech and non-speech auditory objects being replaced and a speech-in-noise task using spoken sentences that must be comprehended in the presence of background speech to examine the extent to which 7-15 year old children with ASD (n = 27) rely on acoustic and semantic information, compared to age-matched (n = 27) and IQ-matched (n = 27) groups of typically developing (TD) children. Within a larger group of 7-15 year old TD children (n = 105) we correlated IQ, ASD symptoms, and the use of acoustic and semantic information.

RESULTS

Children with ASD performed worse overall at the change deafness task relative to the age-matched TD controls, but they did not differ from IQ-matched controls. All groups utilized acoustic and semantic information similarly and displayed an attentional bias towards changes that involved the human voice. Similarly, for the speech-in-noise task, age-matched-but not IQ-matched-TD controls performed better overall than the ASD group. However, all groups used semantic context to a similar degree. Among TD children, neither IQ nor the presence of ASD symptoms predict the use of acoustic or semantic information.

CONCLUSION

Children with and without ASD used acoustic and semantic information similarly during auditory change deafness and speech-in-noise tasks.

Atypical brain lateralization for speech processing at the sublexical level in autistic children revealed by fNIRS

Autistic children often exhibit atypical brain lateralization of language processing, but it is unclear what aspects of language contribute to this phenomenon. This study employed functional near-infrared spectroscopy to measure hemispheric lateralization by estimating hemodynamic responses associated with processing linguistic and non-linguistic auditory stimuli. The study involved a group of autistic children (N = 20, mean age = 5.8 years) and a comparison group of nonautistic peers (N = 20, mean age = 6.5 years). The children were presented with stimuli with systematically decreasing linguistic relevance: naturalistic native speech, meaningless native speech with scrambled word order, nonnative speech, and music. The results revealed that both groups showed left lateralization in the temporal lobe when listening to naturalistic native speech. However, the distinction emerged between autism and nonautistic in terms of processing the linguistic hierarchy. Specifically, the nonautistic comparison group demonstrated a systematic reduction in left lateralization as linguistic relevance decreased. In contrast, the autism group displayed no such pattern and showed no lateralization when listening to scrambled native speech accompanied by enhanced response in the right hemisphere. These results provide evidence of atypical neural specialization for spoken language in preschool- and school-age autistic children and shed new light on the underlying linguistic correlates contributing to such atypicality at the sublexical level.

Reduced Neural Specialization for Word-level Linguistic Prosody in Children with Autism

Children with autism often show atypical brain lateralization for speech and language processing, however, it is unclear what linguistic component contributes to this phenomenon. Here we measured event-related potential (ERP) responses in 21 school-age autistic children and 25 age-matched neurotypical (NT) peers during listening to word-level prosodic stimuli. We found that both groups displayed larger late negative response (LNR) amplitude to native prosody than to nonnative prosody; however, unlike the NT group exhibiting left-lateralized LNR distinction of prosodic phonology, the autism group showed no evidence of LNR lateralization. Moreover, in both groups, the LNR effects were only present for prosodic phonology but not for phoneme-free prosodic acoustics. These results extended the findings of inadequate neural specialization for language in autism to sub-lexical prosodic structures.

Syntactic and affective prosody recognition: Schizophrenia vs. Autism spectrum disorders

Patients with a recent diagnosis of schizophrenia and individuals receiving a diagnosis of autism spectrum disorder without accompanying intellectual impairment (ASD w/o intellectual impairment) during their adulthood share several clinical characteristics. Exploring under-investigated aspects of these two clinical conditions may shed light on their possible connection and facilitate differential diagnosis at very early stages. To this end, we explored the ability of 15 adults with a recent diagnosis of schizophrenia, 15 individuals diagnosed with ASD w/o intellectual impairment as adults, and 15 healthy adults to resolve sentence ambiguities with the use of syntactic prosody, and to decode happiness, anger, sadness, surprise, fear, and neutrality based on affective prosody. Results revealed intact perception of syntactic prosody in adults with schizophrenia, but impaired affective prosody recognition, which could be attributed, however, to emotion processing difficulties overall. On the other hand, individuals with ASD w/o intellectual impairment were impaired on prosody comprehension per se, as evidenced in the most challenging conditions, namely the subject-reading condition and the emotion of surprise. The differences in prosody comprehension ability between the two clinical conditions may serve as an indicator, among other signs, during the diagnostic evaluation.

A profile of prosodic speech differences in individuals with autism spectrum disorder and first-degree relatives

BACKGROUND

Impairments in prosody (e.g., intonation, stress) are among the most notable communication characteristics of individuals with autism spectrum disorder (ASD) and can significantly impact communicative interactions. Evidence suggests that differences in prosody may be evident among first-degree relatives of autistic individuals, indicating that genetic liability to ASD is expressed through prosodic variation, along with subclinical traits referred to as the broad autism phenotype (BAP). This study aimed to further characterize prosodic profiles associated with ASD and the BAP to better understand the clinical and etiologic significance of prosodic differences.

METHOD

Autistic individuals, their parents, and respective control groups completed the Profiling Elements of Prosody in Speech-Communication (PEPS-C), an assessment of receptive and expressive prosody. Responses to expressive subtests were further examined using acoustic analyses. Relationships between PEPS-C performance, acoustic measurements, and pragmatic language ability in conversation were assessed to understand how differences in prosody might contribute to broader ASD-related pragmatic profiles.

RESULTS

In ASD, receptive prosody deficits were observed in contrastive stress. With regard to expressive prosody, both the ASD and ASD Parent groups exhibited reduced accuracy in imitation, lexical stress, and contrastive stress expression compared to respective control groups, though no acoustic differences were noted. In ASD and Control groups, lower accuracy across several PEPS-C subtests and acoustic measurements related to increased pragmatic language violations. In parents, acoustic measurements were tied to broader pragmatic language and personality traits of the BAP.

CONCLUSION

Overlapping areas of expressive prosody differences were identified in ASD and parents, providing evidence that prosody is an important language-related ability that may be impacted by genetic risk of ASD.

Comprehension of Prosodically and Syntactically Marked Focus in Cantonese-Speaking Children With and Without Autism Spectrum Disorder

This study investigated the comprehension of prosodically and syntactically marked focus by 5- to 8-year-old Cantonese-speaking children with and without autism spectrum disorder (ASD). Children listened to question-answer dialogues while looking at pictures depicting the scenarios, and judged whether the answers were correct responses to the questions. The results showed that children with ASD exhibited typically developing (TD)-like performance in the use of syntactic cues to understand focus, although they were significantly slower than their TD peers. However, children with ASD had more difficulties than their TD peers in utilizing prosodic cues in focus comprehension. These findings suggest that the comprehension difficulties found in children with ASD are domain-selective, and children with ASD are sensitive to language-specific focus marking strategies.

The perception of intonational and emotional speech prosody produced with and without a face mask: an exploratory individual differences study

Face masks affect the transmission of speech and obscure facial cues. Here, we examine how this reduction in acoustic and facial information affects a listener's understanding of speech prosody. English sentence pairs that differed in their intonational (statement/question) and emotional (happy/sad) prosody were created. These pairs were recorded by a masked and unmasked speaker and manipulated to contain audio or not. This resulted in a continuum from typical unmasked speech with audio (easiest) to masked speech without audio (hardest). English listeners (N = 129) were tested on their discrimination of these statement/question and happy/sad pairs. We also collected six individual difference measures previously reported to affect various linguistic processes: Autism Spectrum Quotient, musical background, phonological short-term memory (digit span, 2-back), and congruence task (flanker, Simon) behavior. The results indicated that masked statement/question and happy/sad prosodies were harder to discriminate than unmasked prosodies. Masks can therefore make it more difficult to understand a speaker's intended intonation or emotion. Importantly, listeners differed considerably in their ability to understand prosody. When wearing a mask, speakers should try to speak clearer and louder, if possible, and make intentions and emotions explicit to the listener.

Differences in Prediction May Underlie Language Disorder in Autism

Language delay is often one of the first concerns of parents of toddlers with autism spectrum disorder (ASD), and early language abilities predict broader outcomes for children on the autism spectrum. Yet, mechanisms underlying language deficits in autistic children remain underspecified. One prominent component of linguistic behavior is the use of predictions or expectations during learning and processing. Several researcher teams have posited prediction deficit accounts of ASD. The basic assumption of the prediction accounts is that information is processed by making predictions and testing violations against expectations (prediction errors). Flexible (neurotypical) brains attribute differential weights to prediction errors to determine when new learning is appropriate, while autistic individuals are thought to assign disproportionate weight to prediction errors. According to some views, these prediction deficits are hypothesized to lead to higher levels of perceived novelty, resulting in “hyperplasticity” of learning based on the most recent input. In this article, we adopt the perspective that it would be useful to investigate whether language deficits in children with ASD can be attributed to atypical domain-general prediction processes.

An Examination of Articulatory Precision in Autistic Children and Adults

PURPOSE

According to the speech attunement framework, autistic individuals lack the ability and/or motivation to "tune up" their speech to the same level of precision as their neurotypical peers. However, previous studies exploring the articulatory patterns of autistic individuals have yielded disparate findings. One reason contrasting conclusions exist may be because studies have relied on perceptual measures of articulation. Here, we use an objective acoustic measure of articulatory precision to explore the articulatory patterns of autistic children and adults.

METHOD

This was a retrospective analysis of an existing corpus of 900 recorded speech samples taken from 30 adult and 30 child participants across two different population groups: autistic individuals (autism spectrum disorder [ASD] group) and neurotypical individuals (neurotypical [NT] group). Articulatory precision scores were calculated using an automated metric that compares observed acoustics to the expected acoustics for each phoneme production. Linear mixed-effects models were used to compare the articulatory precision scores across population group (i.e., ASD group vs. NT group) and to see if these differences were moderated by age group (i.e., children vs. adult).

RESULTS

The speech of autistic individuals was characterized by reduced articulatory precision relative to their neurotypical peers. This pattern was not significantly moderated by age, indicating it occurred in both the children and adult groups.

CONCLUSIONS

Our preliminary findings indicate that imprecise articulation may be a characteristic of the speech of autistic individuals in both childhood and adulthood. These findings are in line with predictions posited by the speech attunement framework. Given the current lack of speech markers for this clinical population and the importance of speech quality in the social integration of autistic individuals, our results advance articulatory precision as a viable and important target for future research.

The Multidimensional Battery of Prosody Perception (MBOPP)

Prosody can be defined as the rhythm and intonation patterns spanning words, phrases and sentences. Accurate perception of prosody is an important component of many aspects of language processing, such as parsing grammatical structures, recognizing words, and determining where emphasis may be placed. Prosody perception is important for language acquisition and can be impaired in language-related developmental disorders. However, existing assessments of prosodic perception suffer from some shortcomings.  These include being unsuitable for use with typically developing adults due to ceiling effects and failing to allow the investigator to distinguish the unique contributions of individual acoustic features such as pitch and temporal cues. Here we present the Multi-Dimensional Battery of Prosody Perception (MBOPP), a novel tool for the assessment of prosody perception. It consists of two subtests: Linguistic Focus, which measures the ability to hear emphasis or sentential stress, and Phrase Boundaries, which measures the ability to hear where in a compound sentence one phrase ends, and another begins. Perception of individual acoustic dimensions (Pitch and Duration) can be examined separately, and test difficulty can be precisely calibrated by the experimenter because stimuli were created using a continuous voice morph space. We present validation analyses from a sample of 59 individuals and discuss how the battery might be deployed to examine perception of prosody in various populations.

The Multidimensional Battery of Prosody Perception (MBOPP)

Prosody can be defined as the rhythm and intonation patterns spanning words, phrases and sentences. Accurate perception of prosody is an important component of many aspects of language processing, such as parsing grammatical structures, recognizing words, and determining where emphasis may be placed. Prosody perception is important for language acquisition and can be impaired in language-related developmental disorders. However, existing assessments of prosodic perception suffer from some shortcomings.  These include being unsuitable for use with typically developing adults due to ceiling effects and failing to allow the investigator to distinguish the unique contributions of individual acoustic features such as pitch and temporal cues. Here we present the Multi-Dimensional Battery of Prosody Perception (MBOPP), a novel tool for the assessment of prosody perception. It consists of two subtests: Linguistic Focus, which measures the ability to hear emphasis or sentential stress, and Phrase Boundaries, which measures the ability to hear where in a compound sentence one phrase ends, and another begins. Perception of individual acoustic dimensions (Pitch and Duration) can be examined separately, and test difficulty can be precisely calibrated by the experimenter because stimuli were created using a continuous voice morph space. We present validation analyses from a sample of 59 individuals and discuss how the battery might be deployed to examine perception of prosody in various populations.

Autism, music and Alexithymia: A musical intervention to enhance emotion recognition in adolescents with ASD

BACKGROUND

Difficulties identifying and describing emotions in Autism Spectrum Disorder (ASD) have been linked with an increased prevalence of Type 2 Alexithymia. Alexithymia is associated with difficulties in interpreting and verbally labelling physiological arousal. Children and adults with ASD show typical patterns of physiological arousal to music and can attribute verbal labels to musical emotions.

AIM

This pilot study aimed to develop a music-based intervention to improve facial and vocal emotion recognition (ER) and Alexithymia in adolescents with ASD.

METHODS AND PROCEDURES

Adolescents with ASD completed 5 music sessions and pre and post-tests of Alexithymia, ER and language. Each intervention began with a researcher-led group analysis of the emotions expressed in a series of musical excerpts, followed by a group-led discussion of the participants' experiences of these emotions and the ways they may be communicated. Finally, the likely causes and outward expression of these emotions were discussed.

OUTCOME AND RESULTS

Results showed that at pre-test, chronological age (CA) and receptive vocabulary were significantly associated with recognition of facial and verbal emotions and Not hiding emotions. At post-test, older children showed a greater increase in recognition of voices and in emotional bodily awareness. Correlations suggested a trend towards increased ER in voices and faces in children with lower language scores.

CONCLUSIONS AND IMPLICATIONS

Music-based interventions may enhance ER in adolescents with ASD and Alexithymia. Limitations and recommendations for future investigations are discussed.

Developmental differences in neural connectivity for semantic processing in youths with autism

BACKGROUND

Youths with autism spectrum disorder (ASD) rely more on lower-level visual processing as revealed by greater occipital activation, yet less effectively engage higher-level processing of modality-independent semantic knowledge as indicated by reduced frontal activation, compared to typically developing (TD) youths. However, little is known about age-dependent differences in neural connectivity during semantic processing in youths with ASD as compared to TD youths.

METHODS

Four groups were recruited: 31 ASD children (mean age = 10.5 years old), 33 TD children (mean age = 10.4), 30 ASD adolescents (mean age = 14.9), and 34 TD adolescents (mean age = 15.1). We explored their differences in neural connectivity by using functional magnetic resonance imaging (fMRI) with psychophysiological interaction (PPI) during semantic judgments.

RESULTS

In comparison with TD children, children with ASD showed greater activation in the left cuneus and weaker connectivity between the left cuneus and left middle temporal gyrus (MTG). In comparison with TD adolescents, adolescents with ASD showed less activation in the left inferior frontal gyrus (IFG) and weaker functional connectivity between the left IFG and left MTG.

CONCLUSIONS

Children with ASD may rely more on visual processes in the occipital cortex that are disconnected from modality-independent semantics in the temporal cortex. However, adolescents with ASD may less effectively engage frontal mechanisms involved in the top-down control of modality-independent semantic knowledge in the temporal cortex. Our findings provide evidence of developmental differences in the neural substrates of the alterations in semantic processing in youths with ASD compared to TD youths.

Perception and Production of Statement-Question Intonation in Autism Spectrum Disorder: A Developmental Investigation

Prosody or “melody in speech” in autism spectrum disorder (ASD) is often perceived as atypical. This study examined perception and production of statements and questions in 84 children, adolescents and adults with and without ASD, as well as participants’ pitch direction discrimination thresholds. The results suggested that the abilities to discriminate (in both speech and music conditions), identify, and imitate statement-question intonation were intact in individuals with ASD across age cohorts. Sensitivity to pitch direction predicted performance on intonation processing in both groups, who also exhibited similar developmental changes. These findings provide evidence for shared mechanisms in pitch processing between speech and music, as well as associations between low- and high-level pitch processing and between perception and production of pitch.

Improving Emotion Perception in Children with Autism Spectrum Disorder with Computer-Based Training and Hearing Amplification

Individuals with Autism Spectrum Disorder (ASD) experience challenges with social communication, often involving emotional elements of language. This may stem from underlying auditory processing difficulties, especially when incoming speech is nuanced or complex. This study explored the effects of auditory training on social perception abilities of children with ASD. The training combined use of a remote-microphone hearing system and computerized emotion perception training. At baseline, children with ASD had poorer social communication scores and delayed mismatch negativity (MMN) compared to typically developing children. Behavioral results, measured pre- and post-intervention, revealed increased social perception scores in children with ASD to the extent that they outperformed their typically developing peers post-intervention. Electrophysiology results revealed changes in neural responses to emotional speech stimuli. Post-intervention, mismatch responses of children with ASD more closely resembled their neurotypical peers, with shorter MMN latencies, a significantly heightened P2 wave, and greater differentiation of emotional stimuli, consistent with their improved behavioral results. This study sets the foundation for further investigation into connections between auditory processing difficulties and social perception and communication for individuals with ASD, and provides a promising indication that combining amplified hearing and computer-based targeted social perception training using emotional speech stimuli may have neuro-rehabilitative benefits.

Recognition of affective prosody in autism spectrum conditions: A systematic review and meta-analysis

LAY ABSTRACT

Differences in understanding others' emotions and attitudes through features in speech (e.g. intonation) have been observed in individuals with autism spectrum conditions, which contribute greatly to their social communication challenges. However, some studies reported that individuals with autism spectrum condition performed comparably to typically developing individuals on affective prosody recognition. Here, we provide a comprehensive review with statistical analysis of 23 existing studies on this topic to examine potential factors that could explain the discrepancies. Compared with typically developing individuals, autism spectrum condition participants generally appeared to encounter more difficulties in affective prosody recognition. But this finding was likely due to the tendency of the existing research to overly focus on deficits in autism. The affective prosody recognition performance in individuals with autism spectrum condition was closely related to the number of answer options offered to them. Moreover, the degree of difficulty in affective prosody recognition encountered by individuals with autism spectrum condition varied across emotions. The findings of this systematic review highlighted the need for further research on affective prosody recognition in autism (e.g. studies that include tonal language speakers and autism spectrum condition individuals with lower cognitive or verbal abilities).

Irish English PEPS-C (2015 edition) and Learners of ESL

INTRODUCTION

Profiling Elements of Prosody in Speech-Communication (PEPS-C) is a computerised test for assessing the abilities to understand and use speech prosody in communication. It has been used to obtain a profile of strengths and weaknesses in different prosodic forms and functions for different clinical populations (e.g., autism spectrum disorders, Down syndrome) and second language learners. The 2015 edition of PEPS-C incorporates four new subtests addressing the understanding and production of lexical stress and phrasal stress, and collapses four form subtests (Intonation/Short-Item Input and Output, Prosody/Long-Item Input and Output) into two (Discrimination, Imitation). However, the suitability of these new tasks has not been reported in any published studies, although they are likely to be relevant for learners of English. Moreover, the present authors update the Irish English (IE) version of PEPS-C to the 2015 edition for another research project on prosodic skills in children with spina bifida. Hence, this paper reports the making of PEPS-C 2015 (IE) and examines the usefulness of this test in assessing a group of non-native speakers of English, as compared to a group of native speakers of IE.

METHODS

PEPS-C 2015 for Irish English was developed by adapting the test items of the UK English version of the test. The PEPS-C 2015 (IE) was then trialled on 25 native speakers of Irish English and 10 Spanish speakers who speak English as a second language (ESL).

RESULTS

All native speakers of Irish English showed competence (scored ≥75% correct) in the comprehension and expression of prosodic form and functions assessed. For the ESL speakers, the test identified two areas of possible difficulty for this group: Phrase Stress Comprehension and Expression, and Contrastive Stress Comprehension.

CONCLUSION

The PEPS-C 2015, with its extra stress tasks, might therefore be useful as a prosody assessment tool for ESL speakers, particularly those with a Romance first language or at an early stage of learning, but further research is needed.

A meta-analysis of prosody in autism, Williams syndrome, and Down syndrome

Prosody, the rhythm and melody of speech, is an important component of effective communication, and it is an area of difficulty for many populations who struggle with communication. This paper is a meta-analysis of nine studies (and two sets of unpublished data) that assessed prosody using the Profiling Elements of Prosody in Speech-Communication (PEPS-C; Peppé & McCann, 2003) in autism spectrum disorder, Williams syndrome, and Down syndrome. Our original goal was to include studies involving any neurodevelopmental disorder that is commonly associated with intellectual disability, yet our systematic search, which included three databases (i.e., PsychInfo, ERIC, and PubMed), only identified studies involving these three groups. To be included in the meta-analysis, studies had to include a group (n ≥ 3 participants) with a neurodevelopmental disorder commonly associated with intellectual disability and a typically developing comparison group matched on chronological age, nonverbal abilities, or verbal abilities. Studies also needed to report original data using the PEPS-C and be available in English. Study quality was assessed using a checklist adapted from Downes et al. (2016). Results revealed that prosodic form was a weakness for each etiology, while unique patterns of strengths and weaknesses were evident for prosodic functions. Groups with autism (n = 5), all classified as high-functioning or with Asperger's syndrome, exhibited weakness in emotional affect but some relative strengths with turn-end and focus tasks. Groups with Williams syndrome (n = 4) demonstrated weaknesses on phrase/sentence-level tasks and relative strengths on word-level tasks. Groups with Down syndrome (n = 2) had the greatest difficulty overall, though performance was better on receptive (vs. expressive) function tasks. By combining studies and related subtasks of the PEPS-C, we are able to more confidently generalize findings for each population and identify targets for intervention. However, given the limited number of studies identified, this paper also highlights the need for more research on prosody in intellectual disability.

Lexical stress contrastivity in Italian children with autism spectrum disorders: an exploratory acoustic study

We investigated production of lexical stress in children with and without autism spectrum disorders (ASD), all monolingual Italian speakers. The mean age of the 16 autistic children was 5.73 years and the mean age of the 16 typically developing children was 4.65 years. Picture-naming targets were five trisyllabic words that began with a weak-strong pattern of lexical stress across the initial two syllables (WS: matita) and five trisyllabic words beginning with a strong-weak pattern (SW: gomito). Acoustic measures of the duration, fundamental frequency, and intensity of the first two vowels for correct word productions were used to calculate a normalised Pairwise Variability Index (PVI) for WS and SW words. Results of acoustic analyses indicated no statistically significant group differences in PVIs. Results should be interpreted in line with the exploratory nature of this study. We hope this study will encourage additional cross-linguistic studies of prosody in children's speech production.

An acoustic study of lexical stress contrastivity in children with and without autism spectrum disorders

In this exploratory study, we examined stress contrastivity within real word productions elicited via picture naming in 20 children with autism spectrum disorders (ASD) and 20 typical peers group-wise matched on age and vocabulary. Targets had a dominant pattern of lexical stress beginning with a strong-weak pattern (SW: 'caterpillar', 'butterfly') or a non-dominant pattern of lexical stress beginning with a weak-strong pattern (WS: 'tomato', 'potato'). Children produced each target twice (n = 320 productions). Acoustic measures were made for the duration, fundamental frequency, and intensity of the first two vowels for each word production. For vowel duration and fundamental frequency, children with ASD and typical peers produced a similar magnitude of stress contrastivity for SW and WS words. However, there was a significant group difference in the way contrastivity in intensity was realised for WS words whereby children with ASD produced less stress contrastivity than typical peers. Bayesian analyses were in line with our interpretation of our frequentist analyses.

Generalization of content and emotional prosody across speakers varying in gender in youth with Autism Spectrum Disorder

AIMS

We employed a discrimination-choice procedure, embedded in a custom-made videogame, to evaluate whether youth with Autism Spectrum Disorder (ASD), including nonverbal individuals, distinguish sentences on the basis of emotional tone-of-voice and generalize linguistic information across speaker gender.

METHODS AND PROCEDURES

Thirteen youth with ASD (7-21 years) and 13 age-matched typical controls heard pairs of pre-recorded sentences varying in lexical content and prosody (e.g., enthusiastic "Dave rode a bike'' vs. grouchy "Mark held a key''). After training to select a target sentence, participants heard test probes comprising re-combinations of the content and prosodic features of the sentences. Interspersed generalization trials used a voice opposite in gender to the voice used in training.

OUTCOMES AND RESULTS

Youth with ASD were less accurate than controls in discriminating sentences based on emotional tone-of-voice. Nonverbal and verbal youth did not differ in this regard. The ASD group showed only slight decrements in generalizing to the opposite-gender voice.

CONCLUSIONS AND IMPLICATIONS

The finding of intact generalization of linguistic information across male/female speakers contrasts with the widely held view that autism is characterized by deficits in generalization. This suggests the need to test generalization under varying task demands to identify limits on performance.

Discriminating autism and language impairment and specific language impairment through acuity of musical imagery

Deficits in auditory short-term memory have been widely reported in children with Specific Language Impairment (SLI), and recent evidence suggests that children with Autism Spectrum Disorder and co-morbid language impairment (ALI) experience similar difficulties. Music, like language relies on auditory memory and the aim of the study was to extend work investigating the impact of auditory short-term memory impairments to musical perception in children with neurodevelopmental disorders. Groups of children with SLI and ALI were matched on chronological age (CA), receptive vocabulary, non-verbal intelligence and digit span, and compared with CA matched typically developing (TD) controls, on tests of pitch and temporal acuity within a voluntary musical imagery paradigm. The SLI participants performed at significantly lower levels than the ALI and TD groups on both conditions of the task and their musical imagery and digit span scores were positively correlated. In contrast ALI participants performed as well as TD controls on the tempo condition and better than TD controls on the pitch condition of the task. Whilst auditory short-term memory and receptive vocabulary impairments were similar across ALI and SLI groups, these were not associated with a deficit in voluntary musical imagery performance in the ALI group.

The impact of atypical sensory processing on social impairments in autism spectrum disorder

Altered sensory processing has been an important feature of the clinical descriptions of autism spectrum disorder (ASD). There is evidence that sensory dysregulation arises early in the progression of ASD and impacts social functioning. This paper reviews behavioral and neurobiological evidence that describes how sensory deficits across multiple modalities (vision, hearing, touch, olfaction, gustation, and multisensory integration) could impact social functions in ASD. Theoretical models of ASD and their implications for the relationship between sensory and social functioning are discussed. Furthermore, neural differences in anatomy, function, and connectivity of different regions underlying sensory and social processing are also discussed. We conclude that there are multiple mechanisms through which early sensory dysregulation in ASD could cascade into social deficits across development. Future research is needed to clarify these mechanisms, and specific focus should be given to distinguish between deficits in primary sensory processing and altered top-down attentional and cognitive processes.

Reduced tract integrity of the model for social communication is a neural substrate of social communication deficits in autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with social communication deficits as one of the core symptoms. Recently, a five-level model for the social communication has been proposed in which white matter tracts corresponding to each level of the model are identified. Given that the model for social communication subserves social language functions, we hypothesized that the tract integrity of the model for social communication may be reduced in ASD, and the reduction may be related to social communication deficits.

METHODS

Sixty-two right-handed boys with ASD and 55 typically developing (TD) boys received clinical evaluations, intelligence tests, the Social Communication Questionnaire (SCQ), and MRI scans. Generalized fractional anisotropy (GFA) was measured by diffusion spectrum imaging to indicate the microstructural integrity of the tracts for each level of the social communication model. Group difference in the tract integrity and its relationship with the SCQ subscales of social communication and social interaction were investigated.

RESULTS

We found that the GFA values of the superior longitudinal fasciculus III (SLF III, level 1) and the frontal aslant tracts (FAT, level 2) were decreased in ASD compared to TD. Moreover, the GFA values of the SLF III and the FAT were associated with the social interaction subscale in ASD.

CONCLUSIONS

The tract integrity of the model for social communication is reduced in ASD, and the reduction is associated with impaired social interaction. Our results support that reduced tract integrity of the model for social communication might be a neural substrate of social communication deficits in ASD.

Basic and complex emotion recognition in children with autism: cross-cultural findings

BACKGROUND

Children with autism spectrum conditions (ASC) have emotion recognition deficits when tested in different expression modalities (face, voice, body). However, these findings usually focus on basic emotions, using one or two expression modalities. In addition, cultural similarities and differences in emotion recognition patterns in children with ASC have not been explored before. The current study examined the similarities and differences in the recognition of basic and complex emotions by children with ASC and typically developing (TD) controls across three cultures: Israel, Britain, and Sweden.

METHODS

Fifty-five children with high-functioning ASC, aged 5-9, were compared to 58 TD children. On each site, groups were matched on age, sex, and IQ. Children were tested using four tasks, examining recognition of basic and complex emotions from voice recordings, videos of facial and bodily expressions, and emotional video scenarios including all modalities in context.

RESULTS

Compared to their TD peers, children with ASC showed emotion recognition deficits in both basic and complex emotions on all three modalities and their integration in context. Complex emotions were harder to recognize, compared to basic emotions for the entire sample. Cross-cultural agreement was found for all major findings, with minor deviations on the face and body tasks.

CONCLUSIONS

Our findings highlight the multimodal nature of ER deficits in ASC, which exist for basic as well as complex emotions and are relatively stable cross-culturally. Cross-cultural research has the potential to reveal both autism-specific universal deficits and the role that specific cultures play in the way empathy operates in different countries.

Relations Among Detection of Syllable Stress, Speech Abnormalities, and Communicative Ability in Adults With Autism Spectrum Disorders

PURPOSE

To date, the literature on perception of affective, pragmatic, and grammatical prosody abilities in autism spectrum disorders (ASD) has been sparse and contradictory. It is interesting to note that the primary perception of syllable stress within the word structure, which is crucial for all prosody functions, remains relatively unexplored in ASD. Thus, in the current study, we explored syllable stress perception sensitivity and its relationship to speech production abnormalities and communicative ability in adults with ASD.

METHOD

A same-different syllable stress perception task using pairs of identical 4-syllable words was delivered to 42 adults with/without high-functioning ASD, matched for age, to investigate primary speech perception ability in ASD. Speech production and communicative ability in ASD was measured using the Autism Diagnostic Observation Schedule (Lord et al., 2000).

RESULTS

As predicted, the results showed that adults with ASD were less sensitive in making judgments about syllable stress relative to controls. Also, partial correlations revealed a key association of speech production abnormalities with stress perception sensitivity, rather than communicative ability.

CONCLUSIONS

Our findings provide empirical evidence for deficits on primary syllable stress perception in ASD and its role on sociocommunicative difficulties. This information could facilitate the development of effective interventions for speech and language therapy and social communication.

Perception of Melodic Contour and Intonation in Autism Spectrum Disorder: Evidence From Mandarin Speakers

Tone language experience benefits pitch processing in music and speech for typically developing individuals. No known studies have examined pitch processing in individuals with autism who speak a tone language. This study investigated discrimination and identification of melodic contour and speech intonation in a group of Mandarin-speaking individuals with high-functioning autism. Individuals with autism showed superior melodic contour identification but comparable contour discrimination relative to controls. In contrast, these individuals performed worse than controls on both discrimination and identification of speech intonation. These findings provide the first evidence for differential pitch processing in music and speech in tone language speakers with autism, suggesting that tone language experience may not compensate for speech intonation perception deficits in individuals with autism.

Social functioning and autonomic nervous system sensitivity across vocal and musical emotion in Williams syndrome and autism spectrum disorder

Both Williams syndrome (WS) and autism spectrum disorders (ASD) are associated with unusual auditory phenotypes with respect to processing vocal and musical stimuli, which may be shaped by the atypical social profiles that characterize the syndromes. Autonomic nervous system (ANS) reactivity to vocal and musical emotional stimuli was examined in 12 children with WS, 17 children with ASD, and 20 typically developing (TD) children, and related to their level of social functioning. The results of this small-scale study showed that after controlling for between-group differences in cognitive ability, all groups showed similar emotion identification performance across conditions. Additionally, in ASD, lower autonomic reactivity to human voice, and in TD, to musical emotion, was related to more normal social functioning. Compared to TD, both clinical groups showed increased arousal to vocalizations. A further result highlighted uniquely increased arousal to music in WS, contrasted with a decrease in arousal in ASD and TD. The ASD and WS groups exhibited arousal patterns suggestive of diminished habituation to the auditory stimuli. The results are discussed in the context of the clinical presentation of WS and ASD.

Behavioral, perceptual, and neural alterations in sensory and multisensory function in autism spectrum disorder

Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what is currently known about sensory processing in ASD, how sensory function fits within contemporary models of ASD, and what is understood about the differences in the underlying neural processing of sensory and social communication observed between individuals with and without ASD. In addition to highlighting the sensory features associated with ASD, we also emphasize the importance of multisensory processing in building perceptual and cognitive representations, and how deficits in multisensory integration may also be a core characteristic of ASD.

Anatomic and Functional Connectivity Relationship in Autistic Children During Three Different Experimental Conditions

A group of 21 autistic children were studied for determining the relationship between the anatomic (AC) versus functional (FC) connectivity, considering short-range and long-range brain networks. AC was assessed by the DW-MRI technique and FC by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). For short-range connections, basal records, statistical significant correlations were found for all EEG bands in the left hemisphere, but no significant correlations were found for fast EEG frequencies in the right hemisphere. For the V-A condition, significant correlations were mainly diminished for the left hemisphere; for the right hemisphere, no significant correlations were found for the fast EEG frequency bands. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records showed similar correlations for both hemispheres. For the right hemisphere, significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. The V-A experimental condition enriches the AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to full video stimulation (visual and auditory). An impaired audiovisual interaction in the right hemisphere might explain why significant correlations disappeared for the fast EEG frequencies in the VwA experimental condition.

Deficits in auditory processing contribute to impairments in vocal affect recognition in autism spectrum disorders: A MEG study

OBJECTIVE

The primary aim of this study was to examine whether there is an association between magnetoencephalography-based (MEG) indices of basic cortical auditory processing and vocal affect recognition (VAR) ability in individuals with autism spectrum disorder (ASD).

METHOD

MEG data were collected from 25 children/adolescents with ASD and 12 control participants using a paired-tone paradigm to measure quality of auditory physiology, sensory gating, and rapid auditory processing. Group differences were examined in auditory processing and vocal affect recognition ability. The relationship between differences in auditory processing and vocal affect recognition deficits was examined in the ASD group.

RESULTS

Replicating prior studies, participants with ASD showed longer M1n latencies and impaired rapid processing compared with control participants. These variables were significantly related to VAR, with the linear combination of auditory processing variables accounting for approximately 30% of the variability after controlling for age and language skills in participants with ASD.

CONCLUSIONS

VAR deficits in ASD are typically interpreted as part of a core, higher order dysfunction of the "social brain"; however, these results suggest they also may reflect basic deficits in auditory processing that compromise the extraction of socially relevant cues from the auditory environment. As such, they also suggest that therapeutic targeting of sensory dysfunction in ASD may have additional positive implications for other functional deficits.

Emotional prosody perception and its association with pragmatic language in school-aged children with high-function autism

Emotional prosody perception is essential for social communication, but it is still an open issue whether children with high-function autism (HFA) exhibit any prosodic perception deficits or experience selective impairments in recognizing the prosody of positive emotions. Moreover, the associations between prosody perception, pragmatic language, and social adaptation in children with HFA have not been fully explored. This study investigated whether emotional prosody perception for words and sentences in children with HFA (n=25, 6-11 years of age) differed from age-matched, typically developing children (TD, n=25) when presented with an emotional prosody identification task. The Children's Communication Checklist and Vineland Adaptive Behavior Scale were used to assess pragmatic and social adaption abilities. Results show that children with HFA performed poorer than TD children in identifying happy prosody in both emotionally neutral and relevant utterances. In contrast, children with HFA did not exhibit any deficits in identifying sad and angry prosody. Results of correlation analyses revealed a positive association between happy prosody identification and pragmatic function. The findings indicate that school-aged children with HFA experience difficulties in recognizing happy prosody, and that this limitation in prosody perception is associated with their pragmatic and social adaption performances.

Emotional language processing in autism spectrum disorders: a systematic review

In his first description of Autism Spectrum Disorders (ASD), Kanner emphasized emotional impairments by characterizing children with ASD as indifferent to other people, self-absorbed, emotionally cold, distanced, and retracted. Thereafter, emotional impairments became regarded as part of the social impairments of ASD, and research mostly focused on understanding how individuals with ASD recognize visual expressions of emotions from faces and body postures. However, it still remains unclear how emotions are processed outside of the visual domain. This systematic review aims to fill this gap by focusing on impairments of emotional language processing in ASD. We systematically searched PubMed for papers published between 1990 and 2013 using standardized search terms. Studies show that people with ASD are able to correctly classify emotional language stimuli as emotionally positive or negative. However, processing of emotional language stimuli in ASD is associated with atypical patterns of attention and memory performance, as well as abnormal physiological and neural activity. Particularly, younger children with ASD have difficulties in acquiring and developing emotional concepts, and avoid using these in discourse. These emotional language impairments were not consistently associated with age, IQ, or level of development of language skills. We discuss how emotional language impairments fit with existing cognitive theories of ASD, such as central coherence, executive dysfunction, and weak Theory of Mind. We conclude that emotional impairments in ASD may be broader than just a mere consequence of social impairments, and should receive more attention in future research.

Influences of semantic and prosodic cues on word repetition and categorization in autism

PURPOSE

To investigate sensitivity to prosodic and semantic cues to emotion in individuals with high-functioning autism (HFA).

METHOD

Emotional prosody and semantics were independently manipulated to assess the relative influence of prosody versus semantics on speech processing. A sample of 10-year-old typically developing children (n = 10) and children with HFA (n = 10) were asked to repeat words that were either emotionally congruent or incongruent in form and content (Experiment 1A). In a second task (Experiment 1B), the same participants were asked to classify stimuli on the basis of emotional prosody. A final experiment (Experiment 2) focused on sensitivity to congruence in a non-emotional source of variation: talker gender.

RESULTS

The results revealed a selective impairment in spontaneous integration of prosodic and semantic cues to emotion in HFA; however, the same participants were able to categorize emotions on the basis of prosody under reduced task demands. Individuals with HFA were highly sensitive to another surface characteristic in speech: talker gender.

CONCLUSIONS

The study reveals impairment in the spontaneous integration of prosodic and semantic cues to emotion in HFA; however, insensitivity to surface detail, such as prosody, in HFA appears to be highly task dependent and selective to the domain of emotion.

The use of prosody during syntactic processing in children and adolescents with autism spectrum disorders

In this study, we employed an eye-gaze paradigm to explore whether children (ages 8–12) and adolescents (ages 12–18) with autism spectrum disorders (ASDs) are able to use prosodic cues to determine the syntactic structure of an utterance. Persons with ASD were compared to typically developing (TD) peers matched on age, IQ, gender, and receptive language abilities. The stimuli were syntactically ambiguous but had a prosodic break that indicated the appropriate interpretation (feel the frog … with the feathervs.feel … the frog with the feather). We found that all groups were equally sensitive to the initial prosodic cues that were presented. Children and teens with ASD used prosody to interpret the ambiguous phrase as rapidly and efficiently as their TD peers. However, when a different cue was presented in subsequent trials, the younger ASD group was more likely to respond in a manner consistent with the initial prosodic cue rather than the new one. Eye-tracking data indicated that both younger groups (ASD and TD) had trouble shifting their interpretation as the prosodic cue changed, but the younger TD group was able to overcome this interference and produce an action consistent with the prosodic cue.

Prosódia e transtornos da linguagem: levantamento das publicações em periódicos indexados entre 1979 e 2009

Este estudo tem como tema a relação entre a prosódia e os transtornos da linguagem, sendo esta relação investigada a partir do levantamento das publicações indexadas em bases de dados internacionais. A análise dos artigos mostrou que há um crescimento nas publicações que relacionam os transtornos de linguagem aos déficits de produção e percepção da prosódia da fala. Também reforça que, a perda ou dificuldade nas habilidades relativas à prosódia, compromete a função pragmática da linguagem e, portanto, a interação do sujeito em seu meio social. A afasia foi o transtorno mais estudado, provavelmente influenciado também pelo aumento mundial da população de idosos. E o eixo temático mais encontrado nas publicações foi a percepção da fala.

Preserved coupling between the reader's voice and the listener's cortical activity in autism spectrum disorders

Purpose

Investigating the steadiness of the phase-coupling between the time-course of the reader's voice and brain signals of subjects with autism spectrum disorder (ASD) passively listening to connected speech using magnetoencephalography (MEG). In typically developed subjects, such coupling occurs at the right posterior temporal sulcus (pSTS) for frequencies below 1 Hz, and reflects the neural processing of sentence-level rhythmic prosody at the prelexical level.

Methods

Cortical neuromagnetic signals were recorded with MEG (Elekta Oy, Finland) while seven right-handed and native French-speaking ASD subjects (six males, one female, range: 13–20 years) listened to live (Live) or recorded (Recorded) voices continuously reading a text in French for five minutes. Coherence was computed between the reader's voice time-course and ASD subjects' MEG signals. Coherent neural sources were subsequently reconstructed using a beamformer.

Key findings

Significant coupling was found at 0.5 Hz in all ASD subjects in Live and in six subjects in Recorded. Coherent sources were located close to the right pSTS in both conditions. No significant difference was found in coherence levels between Live and Recorded, and between ASD subjects and ten typically developed subjects (right-handed, native French-speaking adults, 5 males, 5 females, age range: 21–38 years) included in a previous study.

Significance

This study discloses a preserved coupling between the reader's voice and ASD subjects' cortical activity at the right pSTS. These findings support the existence of preserved neural processing of sentence-level rhythmic prosody in ASD. The preservation of early cortical processing of prosodic elements in verbal language might be exploited in therapeutic interventions in ASD.

Recognition of facial expressions and prosodic cues with graded emotional intensities in adults with Asperger syndrome

This study investigated the ability of adults with Asperger syndrome to recognize emotional categories of facial expressions and emotional prosodies with graded emotional intensities. The individuals with Asperger syndrome showed poorer recognition performance for angry and sad expressions from both facial and vocal information. The group difference in facial expression recognition was prominent for stimuli with low or intermediate emotional intensities. In contrast to this, the individuals with Asperger syndrome exhibited lower recognition accuracy than typically-developed controls mainly for emotional prosody with high emotional intensity. In facial expression recognition, Asperger and control groups showed an inversion effect for all categories. The magnitude of this effect was less in the Asperger group for angry and sad expressions, presumably attributable to reduced recruitment of the configural mode of face processing. The individuals with Asperger syndrome outperformed the control participants in recognizing inverted sad expressions, indicating enhanced processing of local facial information representing sad emotion. These results suggest that the adults with Asperger syndrome rely on modality-specific strategies in emotion recognition from facial expression and prosodic information.

A comparison of social cognitive profiles in children with autism spectrum disorders and attention-deficit/hyperactivity disorder: a matter of quantitative but not qualitative difference?

The aim of this study was to compare social cognitive profiles of children and adolescents with Autism Spectrum Disorders (ASD) and ADHD. Participants diagnosed with an ASD (n = 137) were compared to participants with ADHD (n = 436) on tests of facial and vocal affect recognition, social judgment and problem-solving, and parent- and teacher-report of social functioning. Both groups performed significantly worse than the normative sample on all measures. Although the ASD group had more severe deficits, the pattern of deficits was surprisingly similar between groups, suggesting that social cognitive deficit patterns may be more similar in ASD and ADHD than previously thought. Thus, like those with ASDs, individuals with ADHD may also need to be routinely considered for treatments targeting social skills.

Attention to lexical stress and early vocabulary growth in 5-month-olds at risk for autism spectrum disorder

Typically developing infants differentiate strong-weak (trochaic) and weak-strong (iambic) stress patterns by 2months of age. The ability to discriminate rhythmical patterns, such as lexical stress, has been argued to facilitate language development, suggesting that a difficulty in discriminating stress might affect early word learning as reflected in vocabulary size. Children with autism spectrum disorder (ASD) often have difficulty in correctly producing lexical stress, yet little is known about how they perceive it. The current study tested 5-month-old infants with typically developing older siblings (SIBS-TD) and infants with an older sibling diagnosed with ASD (SIBS-A) on their ability to differentiate the trochaic and iambic stress patterns of the word form gaba. SIBS-TD infants showed an increased interest in attention to the trochaic stress pattern, which was also positively correlated with vocabulary comprehension at 12months of age. In contrast, SIBS-A infants attended equally to these stress patterns, although this was unrelated to later vocabulary size.

Acoustic Differences In The Imitation Of Prosodic Patterns In Children With Autism Spectrum Disorders

In research, it has been difficult to characterize the prosodic production differences that have been observed clinically in Autism Spectrum Disorders (ASD). Moreover, the nature of these differences has been particularly hard to identify. This study examined one possible contributor to these perceived differences: motor planning. We examined the ability of children and adolescents with ASD to imitate prosodic patterns in comparison to a group with learning disabilities (LD) and a typically-developing (TD) comparison group. Overall, we found that both the ASD and LD groups were significantly worse at perceiving and imitating prosodic patterns than the TD comparison group. Similar to previous studies using non-imitative speech, participants with ASD showed a significantly longer duration of utterances than the two comparison groups when attempting to imitate an intonation pattern. The implications of differences in duration of utterances are discussed. This study also highlights the importance of using clinical comparison groups in studies of language performance in individuals with ASD.

Auditory processing in autism spectrum disorder: a review

For individuals with autism spectrum disorder or 'ASD' the ability to accurately process and interpret auditory information is often difficult. Here we review behavioural, neurophysiological and imaging literature pertaining to this field with the aim of providing a comprehensive account of auditory processing in ASD, and thus an effective tool to aid further research. Literature was sourced from peer-reviewed journals published over the last two decades which best represent research conducted in these areas. Findings show substantial evidence for atypical processing of auditory information in ASD at behavioural and neural levels. Abnormalities are diverse, ranging from atypical perception of various low-level perceptual features (i.e. pitch, loudness) to processing of more complex auditory information such as prosody. Trends across studies suggest auditory processing impairments in ASD are most likely to present during processing of complex auditory information and are more severe for speech than for non-speech stimuli. The interpretation of these findings with respect to various cognitive accounts of ASD is discussed and suggestions offered for further research.

Fragile X mice: reduced long-term potentiation and N-Methyl-D-Aspartate receptor-mediated neurotransmission in dentate gyrus

Fragile X syndrome (FXS) is a monogenic mental retardation syndrome that frequently includes autism. The Fmr1-knockout (Fmr1-KO) mouse, like FXS-affected individuals, lacks the fragile X mental retardation protein (FMRP) and models autism as well as FXS. Limited human data and several mouse models have implicated the hippocampal dentate gyrus (DG) in autism. We therefore investigated whether the Fmr1-KO mouse exhibited functional changes in DG. We found diminished medial perforant path-granule cell long-term potentiation (LTP), complementing previous investigations of synaptic plasticity in Fmr1-KO demonstrating impaired LTP in CA1, neocortex, and amygdala and exaggerated long-term depression in CA1. We also found that peak amplitude of NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) was smaller in Fmr1-KO than control. AMPA receptor-mediated EPSCs were comparable in the two strains, yielding a lower NMDA/AMPA ratio in Fmr1-KO mice and suggesting one mechanism by which absent FMRP might contribute to diminished LTP. The clinical hallmarks of autism include both excessive adherence to patterns and impaired detection of socially important patterns. The DG has a putative role in pattern separation (for time, space, and features) that has been attributed to granule cell number, firing rates, adult neurogenesis, and even perforant path LTP. DG also contributes to pattern completion in CA3 via its mossy fiber efferents, whose terminals include abundant FMRP in "fragile X granules." Together with the present data, these observations suggest that DG is a candidate region for further investigation in autism and that the Fmr1-KO model may be particularly apt.