Development in infants with autism spectrum disorders: a prospective study

BACKGROUND: Autism is rarely diagnosed before three years of age despite evidence suggesting prenatal abnormalities in neurobiological processes. Little is known about when or how development becomes disrupted in the first two years of life in autism. Such information is needed to facilitate early detection and early intervention. METHODS: This prospective study of autism spectrum disorders (ASD) examined development using the Mullen Scales of Early Learning (MSEL) in 87 infants tested at target ages 6, 14, and 24 months. Participants came from infants at high risk (siblings of children with autism) and low risk (no family history of autism) groups. Based on language test scores, Autism Diagnostic Observation Schedule, and clinical judgment at 24 months of age, participants were categorized as: unaffected, ASD, or language delayed (LD). Longitudinal linear regression and ANOVA models were applied to MSEL raw scores, and estimates were compared between the three diagnostic groups. RESULTS: No statistically significant group differences were detected at 6 months. By 14 months of age, the ASD group performed significantly worse than the unaffected group on all scales except Visual Reception. By 24 months of age, the ASD group performed significantly worse than the unaffected group in all domains, and worse than the language delayed group in Gross Motor, Fine Motor, and Receptive Language. The developmental trajectory of the ASD group was slower than the other groups', and showed a significant decrease in development between the first and second birthdays. CONCLUSIONS: Variations from typical and language delayed development are detectable in many children with ASD using a measure of general development by 24 months of age. Unusual slowing in performance occurred between 14 and 24 months of age in ASD.     

Loss of language in early development of autism and specific language impairment

Background: Several authors have highlighted areas of overlap in symptoms and impairment among children with autism spectrum disorder (ASD) and children with specific language impairment (SLI). By contrast, loss of language and broadly defined regression have been reported as relatively specific to autism. We compare the incidence of language loss and language progression of children with autism and SLI. Methods: We used two complementary studies: the Special Needs and Autism Project (SNAP) and the Manchester Language Study (MLS) involving children with SLI. This yielded a combined sample of 368 children (305 males and 63 females) assessed in late childhood for autism, history of language loss, epilepsy, language abilities and nonverbal IQ. Results: language loss occurred in just 1% of children with SLI but in 15% of children classified as having autism or autism spectrum disorder. Loss was more common among children with autism rather than milder ASD and is much less frequently reported when language development is delayed. For children who lost language skills before their first phrases, the phrased speech milestone was postponed but long‐term language skills were not significantly lower than children with autism but without loss. For the few who experienced language loss after acquiring phrased speech, subsequent cognitive performance is more uncertain. Conclusions: Language loss is highly specific to ASD. The underlying developmental abnormality may be more prevalent than raw data might suggest, its possible presence being hidden for children whose language development is delayed.     

Regression in autism: prevalence and associated factors in the CHARGE Study.

OBJECTIVE: The aim of this study was to examine the prevalence of regressive autism and associated demographic, medical, and developmental factors by using 2 different definitions of regression based on the Autism Diagnostic Interview, Revised. METHODS: Subjects were aged 2 to 5 years, with autism (AU) or autism spectrum disorder (ASD) confirmed by standardized measures. Children with regression, defined as a) loss of both language and social skills or b) loss of either language or social skills, were compared with each other and to children with AU or ASD with no reported loss of skills on developmental and adaptive functioning. Parents reported on seizure, gastrointestinal, and sleep concerns. RESULTS: Fifteen percent (50/333) of the combined AU-ASD group lost both language and social skills; 41% (138/333) lost either language or social skills. No differences were found between the 2 samples of children with regression. Few developmental, demographic, or medical differences were found between the combined regression group and children without loss of skills, in both the larger AU-ASD sample and the more homogeneous AU-only sample. Children with regression had significantly lower communication scores than children without regression. CONCLUSIONS: The prevalence of regression in a large sample of young children with AU and ASD varies depending on the definition used; requiring loss of language significantly underestimates the frequency of developmental regression. Children with regression performed significantly less well than those without regression on 2 measures of communication, but the clinical meaningfulness of these differences is uncertain because of the small effect sizes.     

Behavior in children with Down syndrome

Objective  To highlight the differences in behaviors in children with diagnosis of down syndrome. Method  Eight children with Down syndrome who displayed autistic features were compared with eight Down syndrome children without autistic features. These children were randomly selected and were matched for age and level of retardation. Standardized Psychological tests were administered to tap the behavioral differences. Mann-Whitney U test was used for significance of difference between both the groups. Results  Down syndrome children without Autism Spectrum Disorder had better communication and socialization skills than children with Down syndrome with Autism Spectrum Disorder. Down syndrome children with Autism Spectrum Disorder displayed more restricted repetitive and stereotyped patterns of behaviors, interests and activities. Conclusion  Our findings indicate that Autism Spectrum Disorder manifests as a distinct behavioral phenomenon in Down syndrome. Hence it is important for professionals to consider the possibility of a dual diagnosis which will entitle the child to a more specialized and effective educational and intervention services.     

Distinct patterns of grey matter abnormality in high-functioning autism and Asperger's syndrome

Background: Autism exists across a wide spectrum and there is considerable debate as to whether children with Asperger’s syndrome, who have normal language milestones, should be considered to comprise a subgroup distinct other from high‐functioning children with autism (HFA), who have a history of delayed language development. Magnetic resonance imaging (MRI) studies of autism are in disagreement. One possible reason is that the diagnosis of autism takes precedence over Asperger’s syndrome and a distinction in language acquisition is rarely made. We therefore planned to examine a whole brain hypothesis that the patterns of grey matter differences in Asperger’s syndrome and HFA can be distinguished. Methods: We used voxel‐based computational morphometry to map grey matter volume differences in 33 children with either Asperger’s syndrome or high‐functioning autism compared to 55 typical developing control children balanced for age, IQ, gender, maternal language and ethnicity. Results: Children with HFA had significantly smaller grey matter volumes in subcortical, posterior cingulate and precuneus regions than the Asperger’s group. Compared to controls, children with HFA had smaller grey matter volumes in predominantly fronto‐pallidal regions, while children with Asperger’s had less grey matter in mainly bilateral caudate and left thalamus. In addition we found a significant negative correlation between the size of a grey matter cluster around BA44 language area and the age of acquisition of phrase speech in the children with HFA. When the groups were combined we confirmed a mixed picture of smaller grey matter volumes in frontal, basal ganglia, temporal and parietal regions. Conclusions: Our study suggests that the underlying neurobiology in HFA and Asperger’s syndrome is at least partly discrete. Future studies should therefore consider the history of language acquisition as a valuable tool to refine investigation of aetiological factors and management options in pervasive developmental disorders.     

Autism Spectrum Disorders at 20 and 42 Months of Age: Stability of Clinical and ADI-R Diagnosis

The association between, and stability of, clinical diagnosis and diagnosis derived from the Autism Diagnostic Interview-Revised (ADI-R; Lord, Rutter, & Le Couteur, 1994) was examined in a sample of prospectively identified children with childhood autism and other pervasive developmental disorders assessed at the age of 20 months and 42 months. Clinical diagnosis of autism was stable, with all children diagnosed with childhood autism at age 20 months receiving a diagnosis of childhood autism or a related pervasive developmental disorder (PDD) at age 42 months. Clinical diagnosis of childhood autism was also reasonably sensitive, with all children who went on to receive a clinical diagnosis of childhood autism at 42 months being identified as having autism or PDD at 20 months. However, clinical diagnosis for PDD and Asperger's syndrome lacked sensitivity at 20 months, with several children who subsequently received these diagnoses at 42 months receiving diagnoses of language disorder or general developmental delay, as well as in two cases being considered clinically normal, at the earlier timepoint. The ADI-R was found to have good specificity but poor sensitivity at detecting childhood autism at 20 months; however, the stability of diagnosis from 20 to 42 months was good. In addition, the ADI-R at age 20 months was not sensitive to the detection of related PDDs or Asperger's syndrome. The continuity and discontinuity between behavioural abnormalities identified at both timepoints in the three domains of impairment in autism was examined, both in children who met final clinical criteria for an autistic spectrum disorder, and for children with language disorder who did not, as well as for a small sample of typically developing children.     

人神经前体细胞移植治疗儿童广泛性发育障碍初探

目的：观察人神经前体细胞（hNPCs）移植治疗儿童广泛性发育障碍的安全性及疗效。方法：对22例广泛性发育障碍患儿进行研究,其中孤独症9例,Rett综合征13例,经颅骨钻孔侧脑室穿刺注射hNPCs治疗。分别于手术前、术后1个月、术后6个月、术后1年采用孤独症行为评定量表（ABC）对移植患儿进行评估。结果：治疗及随访过程中无严重不良事件发生。移植后22例患儿中,1例失访,17例患儿临床症状出现不同程度的改善,其中孤独症患儿8例,Rett综合征患儿9例。孤独症患儿行ABC量表评估后发现,术后6个月交往因子得分,以及术后1年ABC总分、交往及语言因子得分均低于术前,差异有统计学意义（P<0.05）。结论：临床应用hNPCs移植治疗儿童广泛性发育障碍是安全、可行的,并具有一定疗效,有必要扩大观察病例数进一步研究。     

Trisomie 21 et autisme : double diagnostic, évaluation et intervention

Autism is recognized as an additional diagnosis possible in people with Down syndrome. This pathology is still rarely detected and treated in this population in France. This article is a review of the English literature and of studies led during the last fifteen years. Studies have identified the expression of autism clinical signs in children with Down syndrome and the sensitivity and specificity of diagnostic instruments for autism in this population despite their cognitive impairments. This paper emphasizes authors’ recommendations about intervention taking into account the dual diagnosis: they encourage the identification of autism as well as early and appropriate intervention for those children whose needs differ from their peers without comorbid disorder. These results show the need to educate professionals about the importance of the detection of autism in children with Down syndrome, and the prevention that could follow.     

Autism spectrum disorder in the second year: stability and change in syndrome expression

OBJECTIVES: Increasing numbers of young children referred for a differential diagnosis of autism spectrum disorders (ASD) necessitates better understanding of the early syndrome expression and the utility of the existing state-of-the art diagnostic methods in this population. METHOD: Out of 31 infants under the age of 2 years referred for a differential diagnosis, 19 were diagnosed with autism, and 9 with pervasive developmental disorder - not otherwise specified (PDD-NOS) when reassessed at 3 years. We examined 1) the symptoms of ASD in the second year and changes in the syndrome expression by the age of three; 2) relationship between expert-assigned clinical diagnosis and diagnostic classification based on Autism Diagnostic Observation Schedule-Generic (ADOS-G) and Autism Diagnostic Interview-Revised (ADI-R) in the second year; 3) the relationship between direct observation and parental report of ASD symptoms. RESULTS: Symptoms of autism and PDD-NOS in the second year were pronounced and stability of the clinical diagnosis was high. The agreement between clinician-assigned autism but not PDD-NOS diagnosis and the ADOS-G was high. However, sensitivity of the ADI-R diagnostic classification of autism was poor. Comparison of concurrent parental report and direct observation revealed discrepancies in severity ratings of key dyadic social behaviors. Changes in communication reflected acquisition of language accompanied by the emergence of unusual language characteristics. Symptoms of social dysfunction were relatively stable over time, and so was the severity of stereotyped behaviors. CONCLUSIONS: The study provides support for stability of clinical diagnosis and syndrome expression in the second year and highlights advantages and limitations of the ADI-R and ADOS-G for diagnosing and documenting symptoms of ASD in infants.     

Down综合征患儿睡眠特征多导睡眠图的回顾性研究

目的 探讨Down综合征患儿的睡眠结构和基本睡眠参数的特点。方法 选取10例Down综合征患儿为Down组，采用染色体核型检查进行Down综合征的诊断，其中男7例，女3例，年龄中位数8岁2个月；选取声带小结患儿14例及突发性耳聋6例患儿为对照组，其中男12例，女8例，年龄中位数8岁9个月。两组患儿均接受整夜多导睡眠图监测，按中华医学会耳鼻咽喉科学分会制定的儿童阻塞性睡眠呼吸暂停低通气综合征（OSAHS）诊疗指南（草案）中的标准进行呼吸事件的定义和OSAHS的诊断，阻塞性呼吸暂停指数（OAI）每小时≤1次或呼吸暂停低通气指数(AHI) 每小时≤5次，最低血氧饱和度(LSaO2)≥0.92可以排除OSAHS。应用Mann-Whitney U和精确概率检验，比较Down组和对照组的睡眠结构，并进行睡眠期LSaO2、OAI、AHI、脑电醒觉反应指数及睡眠期肢体运动事件指数的比较。结果 ①两组间在年龄、性别和体重指数等差异无统计学意义（P＞0.05）；②Down组和对照组比较，快动眼睡眠比例减少，且差异有显著统计学意义（Z=-2.6，P= 0.009）；③睡眠期LSaO2较对照组显著下降（P＜0.05），OAI、AHI及睡眠期肢体运动事件指数Down组较对照组显著升高（P＜0.05）；④10例Down综合征患儿中有6例符合OSAHS诊断，6例中有5例为男性。结论 Down综合征患儿存在睡眠呼吸紊乱，应使用多导睡眠检测的方法尽早发现睡眠呼吸紊乱的问题。     

Autistic and dysphasic children. I: Clinical characteristics

Autism and dysphasia are behaviorally defined disorders of higher cerebral function which in preschool children share the common core symptom of impairment of language. In this study we describe the clinical characteristics of 314 autistic and 237 dysphasic nonautistic children evaluated by one child neurologist. There was no significant difference between autistic and dysphasic children in gestational age, birth weight, or prevalence of associated medical disorders, all of which were infrequent, although a positive history of resuscitation or ventilatory support was more common in dysphasic than autistic children (P = .03). As a group autistic children are more likely than dysphasic children to have language subtypes affecting central processing and formulation, a family history of psychiatric disorders and autism, and a history of regression of language and behavior. After excluding 12 girls with autistic symptoms who met the clinical criteria for Rett syndrome, we found that there was no significant difference in the number of autistic and dysphasic children with an abnormal sensorimotor examination. Girls with autism were more likely than boys to have severe mental deficiency (38% of autistic girls vs 23% of boys) (P = 0.012) and a motor deficit (27% vs 11%) (P = .0009).     

Hyperbaric treatment for children with autism: a multicenter, randomized, double-blind, controlled trial

Background

Several uncontrolled studies of hyperbaric treatment in children with autism have reported clinical improvements; however, this treatment has not been evaluated to date with a controlled study. We performed a multicenter, randomized, double-blind, controlled trial to assess the efficacy of hyperbaric treatment in children with autism.

Methods

62 children with autism recruited from 6 centers, ages 2–7 years (mean 4.92 ± 1.21), were randomly assigned to 40 hourly treatments of either hyperbaric treatment at 1.3 atmosphere (atm) and 24% oxygen ("treatment group", n = 33) or slightly pressurized room air at 1.03 atm and 21% oxygen ("control group", n = 29). Outcome measures included Clinical Global Impression (CGI) scale, Aberrant Behavior Checklist (ABC), and Autism Treatment Evaluation Checklist (ATEC).

Results

After 40 sessions, mean physician CGI scores significantly improved in the treatment group compared to controls in overall functioning (p = 0.0008), receptive language (p < 0.0001), social interaction (p = 0.0473), and eye contact (p = 0.0102); 9/30 children (30%) in the treatment group were rated as "very much improved" or "much improved" compared to 2/26 (8%) of controls (p = 0.0471); 24/30 (80%) in the treatment group improved compared to 10/26 (38%) of controls (p = 0.0024). Mean parental CGI scores significantly improved in the treatment group compared to controls in overall functioning (p = 0.0336), receptive language (p = 0.0168), and eye contact (p = 0.0322). On the ABC, significant improvements were observed in the treatment group in total score, irritability, stereotypy, hyperactivity, and speech (p < 0.03 for each), but not in the control group. In the treatment group compared to the control group, mean changes on the ABC total score and subscales were similar except a greater number of children improved in irritability (p = 0.0311). On the ATEC, sensory/cognitive awareness significantly improved (p = 0.0367) in the treatment group compared to the control group. Post-hoc analysis indicated that children over age 5 and children with lower initial autism severity had the most robust improvements. Hyperbaric treatment was safe and well-tolerated.

Conclusion

Children with autism who received hyperbaric treatment at 1.3 atm and 24% oxygen for 40 hourly sessions had significant improvements in overall functioning, receptive language, social interaction, eye contact, and sensory/cognitive awareness compared to children who received slightly pressurized room air.

Trial Registration

clinicaltrials.gov NCT00335790     

Variability in outcome for children with an ASD diagnosis at age 2

BACKGROUND: Few studies have examined the variability in outcomes of children diagnosed with autism spectrum disorder (ASD) at age 2. Research is needed to understand the children whose symptoms - or diagnoses - change over time. The objectives of this study were to examine the behavioral and diagnostic outcomes of a carefully defined sample of 2-year-old children with ASD, and to identify child and environmental factors that contribute to variability in outcomes at age 4. METHODS: Forty-eight children diagnosed with autism or pervasive developmental disorder not otherwise specified (PDDNOS) at age 2 were followed to age 4. Diagnostic measures included the Autism Diagnostic Observation Schedule - Generic (ADOS-G) and clinical diagnosis at ages 2 and 4, and the ADI-R at age 4. RESULTS: Diagnostic stability for an ASD diagnosis (autism or PDDNOS) was 63%, and for an autism diagnosis was 68%. Children who failed to meet diagnostic criteria for ASD at follow-up were more likely to: 1) be 30 months or younger at initial evaluation; 2) have milder symptoms of autism, particularly in the social domain; and 3) have higher cognitive scores at age 2. No differences between children with stable and unstable diagnoses were found for amount of intervention services received. Among the children with unstable diagnoses, all but one continued to have developmental disorders, most commonly in the area of language. CONCLUSIONS: The stability of ASD was lower in the present study than has been reported previously, a finding largely attributable to children who were diagnosed at 30 months or younger. Implications for clinical practice are discussed.     

Sensory Processing and Maladaptive Behavior: Profiles Within the Down Syndrome Phenotype

Aim: Sensory processing impairments are well characterized in children with neurodevelopmental disorders, particularly autism, and have been associated with maladaptive behaviors. However, little is known regarding sensory processing difficulties within Down syndrome, or how these difficulties may influence maladaptive behavior. This study aims to characterize sensory processing difficulties within the Down syndrome phenotype and determine the influence of processing difficulties on maladaptive behavior. Methods: To explore this issue, we administered the Short Sensory Profile and the Developmental Behavior Checklist to parents or primary caregivers of young children with DS (N?=?49; M nonverbal mental age (NVMA)?=?30.92 months (SD?=?12.30); M chronological age (CA)?=?67.04 (SD?=?25.13). Results: Results indicated that Low Energy/Weak, Under-responsive/Seeks Sensation, and Auditory Filtering were the areas of greatest sensory regulation difficulty, and that Self-Absorbed behavior and Disruptive/Antisocial behavior were elevated areas of maladaptive behavior. Multivariate regression analyses indicated that Under-responsive/Seeks Sensation was the only sensory regulation domain significantly associated with Self-Absorbed and Disruptive/Antisocial behavior. Conclusion: Findings indicate a consistent pattern of sensory processing impairments and associations with maladaptive behavior in children with DS. Implications for interventions are discussed.     

Treatment of children with Down syndrome and growth retardation with recombinant human growth hormone.

The effect of recombinant human growth hormone on children with Down syndrome who had growth retardation and microcephaly was examined. Thirteen children with trisomy 21 without congenital heart disease who were short for age (-1.19 to -3.5 standard deviation score) and microcephalic (-1.58 to -6.60 standard deviation score) were given recombinant human growth hormone, 0.1 mg/kg subcutaneously, 3 days a week for 1 year. Before treatment, peak serum growth hormone concentrations were less than 10 micrograms/L after levodopa and clonidine stimulation tests in five patients, after clonidine in three patients, and after levodopa in three patients. Three patients had nocturnal integrated growth hormone concentrations of 0.5, 1.5 and 0.65 micrograms/L, respectively. The mean growth rate before treatment was 5.4 +/- 1.6 cm/yr and increased to 12.2 +/- 3.2 cm/yr (p less than 0.001) after 12 months of recombinant human growth hormone treatment. The mean head circumference standard deviation score before treatment was -3.1 +/- 1.3 and increased to -2.3 +/- 1.2 (p less than 0.001) at 12 months. Bone age before and 1 year after treatment increased in correspondence with chronologic age. Plasma hemoglobin A1c concentration was normal during treatment with recombinant human growth hormone. The mean plasma concentrations of insulin-like growth factor I at baseline and at 12 months were 0.54 +/- 0.19 U/ml and 1.25 +/- 0.97 U/ml, respectively (p less than 0.02). We conclude that recombinant human growth hormone therapy can result in a significant increase in annual growth rate and head circumference in children with Down syndrome, without significant side effects.     

Therapeutic Efficacy and Safety of GH in Japanese Children with Down Syndrome Short Stature Accompanied by GH Deficiency

In this study, we investigated the effects of GH treatment in children with Down syndrome who had been diagnosed with GH deficiency (GHD). A total of 20 subjects were investigated in this study. Fourteen Down syndrome children (5 boys and 9 girls) with short stature due to GHD were treated with GH at Okayama Red Cross General Hospital, and 6 Down syndrome children (4 boys and 2 girls) with short stature due to GHD were registered in the Pfizer International Growth Database (KIGS). Height SD score (SDS) increased throughout the three-year GH treatment period. The overall mean height SDS increased from –3.5 at baseline to –2.5 after 3 yr of treatment. The mean change in height SDS during these 3 yr was 1.1. In addition, height assessment of SD score based on Down syndrome-specific growth data in the Japanese population revealed that the height SDS (Down syndrome) also increased across the 3-yr GH treatment period. The mean change in height SDS (Down syndrome) during these three years was 1.3. GH therapy was effective for Down syndrome short stature accompanied by GHD, and no new safety concerns were found in this study.     

Functional status of school-aged children with Down syndrome

OBJECTIVE: To field test, in questionnaire format, the Functional Independence Measure for Children (WeeFIM, a schedule usually administered by interview) on parents of a cohort of school-aged children with Down syndrome. METHODS: The parents of 211 Western Australian children with Down syndrome participated in the present study, representing 79.9% of all children with Down syndrome in the State. Subjects were identified using two sources: (i) the Birth Defects Registry; and (ii) the Disability Services Commission. RESULTS: The total WeeFIM score was 106.2 +/- 17.0 (mean +/- SD) out of a possible 126. Girls scored higher than boys (108.6 vs 103.6; P = 0.05). Scores increased across all age groups (P < 0.0001), even relative to normative data. Performance was strongest in the transfer and locomotion domains and weakest in social cognition. CONCLUSION: We found that severe functional limitations are rare in school-aged children with Down syndrome. Some support and supervision are required for complex self-care, communication and social skill tasks. This study demonstrates the feasibility of using the WeeFIM for collecting population survey data in children with developmental disability. This may be useful for the longitudinal tracking of such populations, as well as the monitoring of response to interventions.     

The effectiveness of Picture Exchange Communication System (PECS) training for teachers of children with autism: a pragmatic, group randomised controlled trial

OBJECTIVE: To assess the effectiveness of expert training and consultancy for teachers of children with autism spectrum disorder in the use of the Picture Exchange Communication System (PECS). METHOD: Design: Group randomised, controlled trial (3 groups: immediate treatment, delayed treatment, no treatment). Participants: 84 elementary school children, mean age 6.8 years. Treatment: A 2-day PECS workshop for teachers plus 6 half-day, school-based training sessions with expert consultants over 5 months. Outcome measures: Rates of: communicative initiations, use of PECS, and speech in the classroom; Autism Diagnostic Observation Schedule-Generic (ADOS-G) domain scores for Communication and Reciprocal Social Interaction; scores on formal language tests. RESULTS: Controlling for baseline age, developmental quotient (DQ) and language; rates of initiations and PECS usage increased significantly immediately post-treatment (Odds Ratio (OR) of being in a higher ordinal rate category 2.72, 95% confidence interval 1.22-6.09, p < .05 and OR 3.90 (95%CI 1.75-8.68), p < .001, respectively). There were no increases in frequency of speech, or improvements in ADOS-G ratings or language test scores. CONCLUSIONS: The results indicate modest effectiveness of PECS teacher training/consultancy. Rates of pupils' initiations and use of symbols in the classroom increased, although there was no evidence of improvement in other areas of communication. Treatment effects were not maintained once active intervention ceased.     

Outcome at 7 years of children diagnosed with autism at age 2: predictive validity of assessments conducted at 2 and 3 years of age and pattern of symptom change over time

OBJECTIVE: To examine the predictive validity of symptom severity, cognitive and language measures taken at ages 2 and 3 years to outcome at age 7 in a sample of children diagnosed with autism at age 2. METHOD: Twenty-six children diagnosed with autism at age 2 were re-assessed at ages 3 and 7 years. At each age symptom severity, cognitive and language assessments were completed. RESULTS: The pattern of autistic symptom severity varied over time by domain. Across time, children moved across diagnostic boundaries both in terms of clinical diagnosis and in terms of instrument diagnosis on the Autism Diagnostic Interview-Revised (ADI-R). On all measures group variability in scores increased with age. Although non-verbal IQ (NVIQ) for the group as a whole was stable across the 3 assessments, this masked considerable individual instability. Standard assessments at age 2 did not predict outcome at age 7 even within the same domain of functioning. In contrast, standard assessments at age 3 did predict outcome. However, a measure of rate of non-verbal communicative acts taken from an interactive play-based assessment at age 2 was significantly associated with language, communication and social outcomes at age 7. CONCLUSIONS: The trajectory of autism symptoms over time differed in different domains, suggesting that they may be, at least in part, separable. Variability in language, NVIQ and symptom severity increased over time. Caution is required when interpreting the findings from assessments of children with autism at age 2 years. At this age measures of rate of non-verbal communication might be more informative than scores on standard psychometric tests. Predictive validity of assessments at age 3 years was greater.     

Imitation performance in toddlers with autism and those with other developmental disorders

BACKGROUND: The present study sought to examine the specificity, developmental correlates, nature and pervasiveness of imitation deficits very early in the development of autism. METHODS: Subjects were 24 children with autism (mean age 34 months), 18 children with fragile X syndrome, 20 children with other developmental disorders, and 15 typically-developing children. Tasks included manual, oral-facial, and object oriented imitations, developmental measures, joint attention ability, and motor abilities. RESULTS: Children with autism were found to be significantly more impaired in overall imitation abilities, oral-facial imitation, and imitations of actions on objects than children in all of the other groups. Imitation skills of young children with fragile X syndrome were strongly influenced by the absence or presence of symptoms of autism. For children with autism, imitation skills were strongly correlated with autistic symptoms and joint attention, even when controlling for developmental level. For comparison groups, imitation was related to other developmental abilities including play, language, and visual spatial skills. Neither motor functioning nor social responsivity accounted for a significant amount of variance in imitation scores, when controlling for overall developmental level, which accounted for much of the variation in imitation ability. CONCLUSIONS: Simple imitation skills were differentially impaired in young children with autism, and lack of social cooperation did not account for their poor performance. In autism, imitation skills clustered with dyadic and triadic social interactions and overall developmental level, but were not related to play or language development. For comparison children, all these areas were inter-related. Hypotheses about a specific dyspraxic deficit underlying the imitation performance in autism were not supported.