Delayed automatic detection of change in speech sounds in adults with autism: a magnetoencephalographic study.

OBJECTIVE: Autism is a form of pervasive developmental disorder in which dysfunction in interpersonal relationships and communication is fundamental. This study evaluated neurophysiological abnormalities at the basic level of language processing, i.e. automatic change detection of speech and non-speech sounds, using magnetoencephalographic recording of mismatch response elicited by change in vowels and tones. METHODS: The auditory magnetic mismatch field (MMF) was evaluated in 9 adults with autism and 19 control subjects using whole-head magnetoencephalography. The MMF in response to the duration change of a pure tone or vowel /a/ and that in response to across-phoneme change between vowels /a/ and /o/, were recorded. RESULTS: The groups were not significantly different in MMF power under any conditions. However, the autism group showed a left-biased latency prolongation of the MMF particularly under the across-phoneme change condition, and this latency delay was significantly associated with greater symptom severity. CONCLUSIONS: These results suggest that adults with autism are associated with delayed processing for automatic change detection of speech sounds. These electrophysiological abnormalities at the earliest level of information processing may contribute to the basis for language deficits observed in autism. SIGNIFICANCE: These results provide the first evidence for delayed latency of phonetic MMF in adults with autism.     

Delayed magnetic mismatch negativity field, but not auditory M100 response, in specific language impairment

Recent studies show that electrophysiological markers of auditory processing such as the cortical 100 ms response (M100) and the mismatch field, derived from magnetoencephalography, might be used to identify children with autism spectrum disorders--M100 peak latency--and to stratify children with autism according to the degree of language impairment--mismatch field peak latency. The present study examined the latency of right superior temporal gyrus M100 and mismatch field in a cohort of children and young adolescents with specific language impairment (n=17), in comparison with age-matched and nonverbal intelligence quotient-matched typically developing controls (n=21). Neither group showed symptoms associated with autism. Although M100 latency (reflecting early auditory processing) did not distinguish controls from children with specific language impairment, the later 'change detection' mismatch field response was significantly delayed (by >50 ms) in the specific language impairment group. Linear discriminant analysis confirmed the role of mismatch field latency (92%) but not M100 latency (8%) in distinguishing groups. The present results lend support to the claim that a delayed M100 is specific to autism spectrum disorders (with relative independence of degree of language impairment) and that a delayed mismatch field reflects an abnormality more generally associated with language impairment, suggesting that mismatch field delay in the present specific language impairment group and previously reported in autistic children with language impairment may be indicative of a common neural system dysfunction.     

Magnetoencephalography identifies rapid temporal processing deficit in autism and language impairment

Deficient rapid temporal processing may contribute to impaired language development by interfering with the processing of brief acoustic transitions crucial for speech perception. Using magnetoencephalography, evoked neural activity (M50, M100) to two 40 ms tones passively presented in rapid succession was recorded in 10 neurologically normal adults and 40 8-17-year-olds with autism, specific language impairment, Asperger syndrome or typical development. While 80% of study participants with intact language (Asperger syndrome, typical development, adults) showed identifiable responses to the second tone, which presented rapid temporal processing demands, 65% of study participants with impaired language (autism, specific language impairment) did not, despite having shown identifiable responses to the first tone. Rapid temporal processing impairments may be fundamentally associated with impairments in language rather than autism spectrum disorder.     

Cortical sound processing in children with autism disorder: an MEG investigation

Previous work investigating frequency encoding mechanisms in human auditory cortex has provided evidence that latency of the auditory evoked M100 is strongly proportional to frequency, with low frequency (100-200 Hz) tones associated with approximately 30 ms longer latencies than mid-range frequency (1-2 kHz) tones. Motivated by pervasive speech and auditory perception deficits observed in autism spectrum disorder, we evaluated M100 frequency dependence in children with autism disorder and typically developing controls. Results indicate that for control children, the dynamic range of frequency modulation was similar to previous reports for healthy adults. Children with autism had a much reduced range of modulation in right hemisphere sites. Findings indicate that frequency encoding mechanisms may follow a differential maturational path in autism spectrum disorder.     

Israeli children with autism spectrum disorder are not macrocephalic

The prevalence of macrocephaly in autism spectrum disorder is reported to be much higher than in the general population, 12% to 37%. Progressive macrocephaly is even considered a warning sign for the development of autism. We evaluated the prevalence of an abnormal head circumference in children with autism in Israel and compared it with the head circumferences of children with developmental language disorder and children with normal development. We did not find a higher prevalence of macrocephaly among Israeli children with autism spectrum disorder (4.4%). Although children with autism spectrum disorder had a significantly higher rate of a head circumference above the 75th percentile compared with children with developmental language disorder, it was not significantly different compared with normal controls. We conclude that there is no increased prevalence of macrocephaly in Israeli children with autism; this can be attributed to a different genetic background.     

Language Impairment and Early Social Competence in Preschoolers with Autism Spectrum Disorders: A Comparison of DSM-5 Profiles

Children with autism spectrum disorder (ASD) and structural language impairment (LI) may be at risk of more adverse social-developmental outcomes. We examined trajectories of early social competence (using the Vineland-II) in 330 children aged 2–4 years recently diagnosed with ASD, and compared 3 subgroups classified by: language impairment (ASD/LI); intellectual disability (ASD/ID) and ASD without LI or ID (ASD/alone). Children with ASD/LI were significantly more socially impaired at baseline than the ASD/alone subgroup, and less impaired than those with ASD/ID. Growth in social competence was significantly slower for the ASD/ID group. Many preschool-aged children with ASD/LI at time of diagnosis resembled “late talkers” who appeared to catch up linguistically. Children with ASD/ID were more severely impaired and continued to lag further behind.     

Evaluation of neuromotor deficits in children with autism and children with a specific speech and language disorder

Several studies have described problems in motor functions in children with autism and children with a specific speech and language disorder. The purpose of this study was to identify neuromotor deficits in these neurodevelopmentally impaired children. A standardised neurological examination was performed in 11 children with childhood autism, 11 children with an expressive language disorder, 11 children with a receptive language disorder and 11 control children. The children were matched for age and non-verbal IQ, not for gender. All children had a non-verbal IQ above 85. The neurological examination procedure allowed for a qualitative and quantitative assessment of five specific neurological subsystems: fine and gross motor functions, balance, coordination and oral motor functions. The high-functioning children with autism and the children with a specific language disorder (expressive or receptive) had more motor problems than the control children on most neurological subsystems. There were few statistically significant differences between the three groups of developmentally impaired children. The frequent co-occurrence of verbal and non-verbal, in particular neuromotor, deficits in developmentally impaired children put an additional burden on the development of these children and should be diagnosed as early as possible. Accepted: 8 May 2002 The research was funded by grant AM 63/4–2 of the Deutsche Forschungsgemeinschaft. Correspondence to Dr. M. Noterdaeme     

Are different kinds of acoustic features processed differently for speech and non-speech sounds?

This study examined how changes in different types of acoustic features are processed in the brain for both speech and non-speech sounds. Event-related potentials (ERPs) were recorded in native Finnish speakers presented with sequences of repetitive vowels (/e/) or complex harmonical tones interspersed with infrequent changes in duration, frequency and either a vowel change (/o/ for vowel sequences) or a double deviant (frequency+duration change for tone sequences). The stimuli were presented monaurally in separate blocks to either the left or right ear. The results showed that speech stimuli were more efficiently processed than harmonical tones as reflected by an enhanced mismatch negativity (MMN) and P3a ERP components. In addition, the duration change in vowels elicited a larger MMN component than the equivalent change in tones. This result might reflect enhanced processing of duration features in the Finnish language in which phoneme duration plays a critical role.     

Predictors and Correlates of Adaptive Functioning in Children with Developmental Disorders

Autism is a developmental disorder marked by impairments in socialization, communication, and perseverative behavior and is associated with cognitive impairment and deficits in adaptive functioning. Research has consistently demonstrated that children with autism have deficits in adaptive functioning more severe than their cognitive deficits. This study investigates the correlates and predictors of adaptive functioning as measured by the Vineland Adaptive Behavior Scales in high- and low-functioning children with autism and their age and nonverbal IQ matched controls. Thirty-five 9-year-old children with high-functioning autism (HAD) were compared with 31 age-matched children with developmental language disorder (DLD), and 40 9-year-old children with low-functioning autism (LAD) were compared with 17 age-matched children with low IQ on adaptive functioning, IQ, autistic symptomology, and tests of language and verbal memory. Results indicate that both groups with autism were significantly impaired compared to their matched controls on Socialization and Daily Living, but not Communication and that these impairments were more pronounced in the HAD group than in the LAD group. Adaptive behavior was strongly correlated with autistic symptomology only in the HAD group. Regression analyses indicated that IQ was strongly predictive of adaptive behavior in both low-functioning groups, but tests of language and verbal memory predicted adaptive behavior in the higher functioning groups. Results suggest that IQ may act as a limiting factor for lower functioning children but higher functioning children are impaired by specific deficits, including autistic symptomology and impaired language and verbal memory.     

Structural asymmetries of language-related gray and white matter and their relationship to language function in young children with ASD

Children with autism spectrum disorder (ASD) are highly variable in their language abilities, but the neural bases of these individual differences are poorly understood. Structural magnetic resonance imaging (MRI) and magnetic resonance diffusion tensor imaging (DTI) tractography were used to examine asymmetries in language-related gray- and white-matter and their relationships to language ability in a sample of 20 children with ASD, aged 4–7 years, and a reference sample of 20 typically developing (TD) children, aged 6–11 years. Children with ASD did not differ significantly from TD children in gray matter asymmetries, but were significantly less left-lateralized than TD children in the volume and radial diffusivity (RD) of the arcuate fasciculus (AF). They did not differ in the fractional anisotropy (FA) or the mean or axial diffusivity of the AF. Within the ASD group, exploratory analyses revealed that decreased leftward/increased rightward asymmetry of pars opercularis was associated with higher language ability and bilaterally increased FA and decreased RD of the AF. In conclusion, children with ASD exhibited atypical asymmetry in language-related white-matter structure as well as an atypical pattern of brain-language relationships that suggest that they may meet language milestones and acquire normal language via a different neurodevelopmental trajectory from TD children.     

Follow-up of children with language delay and features of autism from preschool years to middle childhood

Eighteen children (13 males, five females) who had severe developmental language delay/disorder and some features of autism (although insufficient in severity and combination to meet ICD-10 diagnostic criteria for childhood autism) at preschool age (Time 1; mean age 4 years 4 months) were followed up 4 years later (Time 2; mean age 8 years 7 months). At the initial assessment the diagnostic dilemma was how much the social communication impairments and behavioural problems were secondary to the language problem and how much they constituted a genuine case of a pervasive developmental disorder. It was anticipated that at follow-up some children would continue to show social impairments but that in others social impairments would have receded as language competence improved. Follow-up assessments included the Wechsler Intelligence Scale for Children, the Clinical Evaluation of Language Fundamentals, the Children's Communication Checklist, and the Social Communication Questionnaire. At follow-up, five children had continuing language disorder and were considered to fulfil diagnostic criteria for childhood autism, four children had continuing language disorder and met criteria for atypical autism, and nine met criteria for atypical autism but had somewhat recovered language skills. Thus, even in the subgroup of children whose language ability had improved the features of autism had not dissipated. Severity of social communication impairments and repetitive behaviours at Time 1, rated retrospectively from case notes, were associated with severity of autism symptoms and pragmatic competence at Time 2. The findings are discussed in relation to the unclear boundary between autism spectrum disorders and language delay/disorder.     

Evidence for Distinct Cognitive Profiles in Autism Spectrum Disorders and Specific Language Impairment

Findings that a subgroup of children with an autism spectrum disorder (ASD) have linguistic capabilities that resemble specific language impairment (SLI) have led some authors to hypothesise that ASD and SLI have a shared aetiology. While considerable research has explored overlap in the language phenotypes of the two conditions, little research has examined possible overlap in cognitive characteristics. In this study, we explored nonword and sentence repetition performance, as well as performance on the Children’s Embedded Figures Test (CEFT) for children with ASD or SLI. As expected, ‘language impaired’ children with ASD (ALI) and children with SLI performed worse than both ‘language normal’ ASD (ALN) and typically developing (TD) children on the nonword and sentence repetition tests. Further, the SLI children performed worse than all other groups on the CEFT. This finding supports distinct cognitive profiles in ASD and SLI and may provide further evidence for distinct aetiological mechanisms in the two conditions.     

Effects of antidepressive therapy on auditory processing in severely depressed patients: a combined MRS and MEG study

BACKGROUND: Alterations in brain metabolism as well as in brain function in different brain areas can be observed in severely depressed patients. METHODS: The present study combined proton magnetic resonance spectroscopy (1H MRS, n=16; healthy controls n=27) and magnetoencephalography (MEG, n=17, controls n=18) of the left auditory cortex in severely depressed inpatients pre- and post successful antidepressive therapy. For MEG recordings, patients were stimulated with trains of 4 successive vowels or 4 sine tones, respectively. For each of the 4 stimuli, the amplitude and latency of the N1m was calculated. As a measure of habituation the decrease of the individual amplitudes of the second, third and fourth N1m compared to the first N1m was calculated. RESULTS: Prior to therapy, a subset of patients presented clearly disturbed auditory processing to stimuli (missing of distinct N1m1 and subsequent habituation; 5 of 17 patients (vowels) and 9/17 (tones, respectively)). After treatment, compared to controls, a normalized habituation pattern was observed in all patients for vowels, but not for tones. In contrast, MRS revealed no significant differences between the metabolite concentrations of patients and healthy controls in both measurements. CONCLUSION: Depression may be accompanied by impaired auditory processing, which seems to improve with reduction in depressive symptoms. Auditory cortical dysfunction probably reflects only a part from more widespread aberrations of brain function occurring with severe mood disorder.     

Diagnostic assessment of communicative and interactive behaviours in children with autism and receptive language disorder

 Children with autism and children with a severe specific receptive language disorder both show clear deficits in communicative language skills and in social relationships. In this study the usefulness of the Autism Diagnostic Observation Schedule (ADOS) in the differential diagnosis between these two groups of developmentally impaired children is assessed. 11 children with early infantile autism and 20 children with a specific receptive language disorder participated in the study. 18 children with an expressive language disorder were used as a control group. The ADOS was individually administered to all children by the same examiner. The results showed that on most of the ADOS measures the autistic children were clearly more deviant than the language impaired children. There were no significant differences between the two groups of language impaired children. Eight out of 11 autistic children reached the defined cut-off values on the measures “language and communication” and “social interaction” of the ADOS algorithm, whereas only three autistic children did so on the measure “stereotyped behaviour”. None of the language-impaired children reached the cut-off values on more than one measure. The ADOS allowed for good assessment of certain types of behaviour. However, to confirm the diagnosis of infantile autism, additional information from parents is required. Accepted: 15 February 2000     

Communicative Competence and Metalinguistic Ability: Performance by Children and Adults with Autism Spectrum Disorder

The Test of Language Competence-Expanded Edition (TLC-E) was administered to children and adults with a diagnosis of autism spectrum disorder (ASD). Relative to controls, those with ASD were less competent on a range of TLC-E tasks. No differences were found for either child or adult ASD groups on any of the TLC-E measures when re-classified as Asperger syndrome (AS) and high functioning autism (HFA) using DSM-IV language criterion. Hierarchical cluster analyses of individuals with ASD identified subgroups within the spectrum. The use of developmental language history as an identifying marker in autism is questioned. The findings suggest that comprehensive language assessments on individuals with ASD can provide clinically relevant information regarding the heterogeneity of language skills within the autistic spectrum.     

Early language milestones predict later language,but not autism symptoms in higher functioning children with autism spectrum disorders

Language ability is a known predictor of outcome in children with autism but plays a more controversial role for higher functioning children with autism spectrum disorders (ASD). We studied the relationship between early language milestones and later structural language, adaptive functioning and autism symptoms in a sample of 76 children (mean age = 9.1 years) with an ASD, using two different language milestones: first phrase by 24 or 36 months. After controlling for age and nonverbal abilities, retrospectively reported early language milestones were predictive of later structural language abilities, measured by a sentence repetition task, and adaptive communication skills, but not autism symptoms or adaptive social skills. Acquisition of phrase speech by 24 months was sensitive to language and communication impairments in our ASD group, the majority (84%) of which had already acquired phrase speech by 36 months of age. Early available and easily collectable milestone data may be a useful marker of later language performance even in higher functioning, verbal children on the autism spectrum. When a detailed assessment of language is not possible, data on early milestones may be useful for identifying children at-risk in clinical settings and for language phenotyping in the laboratory.     

Effect of attention on central auditory processing: an fMRI study

Functional magnetic resonance imaging was used to investigate preattentive and attentional processing of auditory stimuli in 18 right-handed normal volunteers. Responses to trains of 1000-Hz pure tones and infrequent (15%) deviant 1300-Hz tones were characterized while subjects ignored all tones; listened for deviants in the left ear; or listened for deviants in the right ear. Preattentive detection of deviants, associated with the mismatch negativity in electrophysiology, was associated with bilateral temporal lobe activation, with a rightward predominance. Processing of deviant stimuli while attending to either ear produced a more robust and widespread activation of these temporal regions, again with a rightward predominance. Thus, preattentive tone processing appears to be linked to asymmetric activation of a core set of temporal regions in which activity is significantly amplified by selective attention. Extratemporal regions activated by attending to targets in either ear included the anterior cingulate cortex, supramarginal gyrus, and dorsolateral prefrontal cortex.     

EFFECT OF ATTENTION ON CENTRAL AUDITORY PROCESSING: AN fMRI STUDY

Functional magnetic resonance imaging was used to investigate preattentive and attentional processing of auditory stimuli in 18 right-handed normal volunteers. Responses to trains of 1000-Hz pure tones and infrequent (15%) deviant 1300-Hz tones were characterized while subjects ignored all tones; listened for deviants in the left ear; or listened for deviants in the right ear. Preattentive detection of deviants, associated with the mismatch negativity in electrophysiology, was associated with bilateral temporal lobe activation, with a rightward predominance. Processing of deviant stimuli while attending to either ear produced a more robust and widespread activation of these temporal regions, again with a rightward predominance. Thus, preattentive tone processing appears to be linked to asymmetric activation of a core set of temporal regions in which activity is significantly amplified by selective attention. Extratemporal regions activated by attending to targets in either ear included the anterior cingulate cortex, supramarginal gyrus, and dorsolateral prefrontal cortex.     

Neuropsychiatric and neurodevelopmental outcome of children at age 6 and 7 years who screened positive for language problems at 30 months

We present a prospective study at school age of neuropsychiatric and neurodevelopmental outcome of language delay suspected at child health screening around 30 months of age. In a community sample, 25 children (21 males, 4 females) screening positive and 80 children (38 males, 42 females) screening negative for speech and language problems at age 30 months were examined in detail for language disorders at age 6 years. The screen-positive children were then followed for another year and underwent in-depth neuropsychiatric examination by assessors blind to the results of previous testing. Detailed follow-up results at age 7 years were available for 21 children. Thirteen of these 21 children (62%) had a major neuropsychiatric diagnosis (autism, atypical autism, Asperger's syndrome, attention-deficit-hyperactivity disorder [ADHD]), or combinations of these. Two further children (10%) had borderline IQ with no other major diagnosis. We conclude that children in the general population who screen positive for speech and language problems before age 3 years appear to be at very high risk of autism spectrum disorders or ADHD, or both, at 7 years of age. Remaining language problems at age 6 years strongly predict the presence of neuropsychiatric or neurodevelopmental disorders at age 7 years.