Marianne Barton

The Modified Checklist for Autism in Toddlers: An Initial Study Investigating the Early Detection of Autism and Pervasive Developmental Disorders

Autism, a severe disorder of development, is difficult to detect in very young children. However, children who receive early intervention have improved long-term prognoses. The Modified Checklist for Autism in Toddlers (M-CHAT), consisting of 23 yes/no items, was used to screen 1,293 children. Of the 58 children given a diagnostic/developmental evaluation, 39 were diagnosed with a disorder on the autism spectrum. Six items pertaining to social relatedness and communication were found to have the best discriminability between children diagnosed with and without autism/PDD. Cutoff scores were created for the best items and the total checklist. Results indicate that the M-CHAT is a promising instrument for the early detection of autism.

Validation of the Modified Checklist for Autism in Toddlers, Revised With Follow-up (M-CHAT-R/F)

OBJECTIVE: This study validates the Modified Checklist for Autism in Toddlers, Revised with Follow-up (M-CHAT-R/F), a screening tool for low-risk toddlers, and demonstrates improved utility compared with the original M-CHAT. METHODS: Toddlers (N = 16 071) were screened during 18- and 24-month well-child care visits in metropolitan Atlanta and Connecticut. Parents of toddlers at risk on M-CHAT-R completed follow-up; those who continued to show risk were evaluated. RESULTS: The reliability and validity of the M-CHAT-R/F were demonstrated, and optimal scoring was determined by using receiver operating characteristic curves. Children whose total score was ≥3 initially and ≥2 after follow-up had a 47.5% risk of being diagnosed with autism spectrum disorder (ASD; confidence interval [95% CI]: 0.41–0.54) and a 94.6% risk of any developmental delay or concern (95% CI: 0.92–0.98). Total score was more effective than alternative scores. An algorithm based on 3 risk levels is recommended to maximize clinical utility and to reduce age of diagnosis and onset of early intervention. The M-CHAT-R detects ASD at a higher rate compared with the M-CHAT while also reducing the number of children needing the follow-up. Children in the current study were diagnosed 2 years younger than the national median age of diagnosis. CONCLUSIONS: The M-CHAT-R/F detects many cases of ASD in toddlers; physicians using the 2-stage screener can be confident that most screen-positive cases warrant evaluation and referral for early intervention. Widespread implementation of universal screening can lower the age of ASD diagnosis by 2 years compared with recent surveillance findings, increasing time available for early intervention.

Large-Scale Use of the Modified Checklist for Autism in Low-Risk Toddlers

OBJECTIVE: The purpose of the study was to examine use of the Modified Checklist for Autism in Toddlers (M-CHAT) as an autism-specific screening instrument in a large, geographically diverse pediatrics-based sample. METHODS: The M-CHAT and the M-CHAT Follow-Up (M-CHAT/F) were used to screen 18 989 toddlers at pediatric well-child visits in 2 US geographic regions. Pediatricians directly referred children to ascertain potential missed screening cases. Screen-positive children received the M-CHAT/F; children who continued to screen positive after the M-CHAT/F received a diagnostic evaluation. RESULTS: Results indicated that 54% of children who screened positive on the M-CHAT and M-CHAT/F presented with an autism spectrum disorder (ASD), and 98% presented with clinically significant developmental concerns warranting intervention. An M-CHAT total score cutoff of ≥3 identifies nearly all screen-positive cases, and for ease of scoring the use of only the M-CHAT total score cutoff is recommended. An M-CHAT total score of 7 serves as an appropriate clinical cutoff, and providers can bypass the M-CHAT/F and refer immediately to evaluation and intervention if a child obtains a score of ≥7. CONCLUSIONS: This study provides empirical support for the utility of population screening for ASD with the use of the M-CHAT in a primary care setting. Results suggest that the M-CHAT continues to be an effective screening instrument for ASD when the 2-step screening process is used. The M-CHAT is widely used at pediatric offices, and this study provides updated results to facilitate use and scoring of the M-CHAT by clinical providers.

Screening for autism in older and younger toddlers with the Modified Checklist for Autism in Toddlers

The Modified Checklist for Autism in Toddlers (M—CHAT) was used to screen younger (16—23 months) versus older (24—30 months) high- and low-risk toddlers. Refusal rates for follow-up interview showed no group differences, but parents of younger/low-risk children were more likely to refuse evaluation than parents of high-risk children. PPP for an ASD diagnosis was: younger/high-risk 0.79, older/high-risk 0.74, younger/low-risk 0.28, and older/low-risk 0.61, with PPP differing by age within the low-risk group. Most of the children in all groups, however, were diagnosed with a developmental disorder. Symptom severity generally did not differ among groups. Cognitive and adaptive measures showed minimal group differences. Therefore, older and younger toddlers had similar symptomatology and developmental delays; PPP for ASD is better at 24 than 18 months for low-risk children; however, these children are still highly likely to show a developmental disorder. Clinical decision making should balance early identification against the lower specificity of M—CHAT screening for the younger/low-risk group.

Screening Young Children for Autism Spectrum Disorders in Primary Practice

The increasing prevalence of autism spectrum disorders as well as emerging evidence of the efficacy of early intervention has focused attention on the need for early identification of young children suspected of having an ASSD. Several studies have suggested that while parents report concerns early in development, it may be months before children can be evaluated and services provided, and these delays may be even more marked in under-served populations. The American Academy of Pediatrics recently recommended universal screening for autism spectrum disorders at the 18- and 24-month well-child pediatric visit. The authors review several early screening tools currently in use and offer recommendations for integrating autism specific screening into primary care practice.

Intervention for optimal outcome in children and adolescents with a history of autism.

Objective: Autism spectrum disorders (ASDs) were once considered lifelong disorders, but recent findings indicate that some children with ASDs no longer meet diagnostic criteria for any ASD and reach normal cognitive function. These children are considered to have achieved “optimal outcomes” (OO). The present study aimed to retrospectively examine group differences in the intervention history of children and adolescents with OO and those with high-functioning autism (HFA). Method: The current study examined intervention histories in 25 individuals with OO and 34 individuals with HFA (current age, 8–21 years), who did not differ on age, sex, nonverbal intelligence, or family income. Intervention history was collected through detailed parent questionnaires. Results: Children in the OO group had earlier parental concern, received earlier referrals to specialists, and had earlier and more intensive intervention than those in the HFA group. Substantially more children with OO than HFA received applied behavior analysis (ABA) therapy, although for children who received ABA, the intensity did not differ between the groups. Children in the HFA group were more likely to have received medication, especially antipsychotics and antidepressants. There were no group differences in the percent of children receiving special diets or supplements. Conclusion: These data suggest that OO individuals generally receive earlier, more intense interventions, and more ABA, whereas HFA individuals receive more pharmacologic treatments. Although the use of retrospective data is a clear limitation to the current study, the substantial differences in the reported provision of early intervention, and ABA in particular, is highly suggestive and should be replicated in prospective studies.

Narrative Performance of Optimal Outcome Children and Adolescents with a History of an Autism Spectrum Disorder (ASD)

Autism Spectrum Disorders (ASDs) have traditionally been considered a lifelong condition; however, a subset of people makes such significant improvements that they no longer meet diagnostic criteria for an ASD. The current study examines whether these “optimal outcome” (OO) children and adolescents continue to have subtle pragmatic language deficits. The narratives of 15 OO individuals, 15 high-functioning individuals with an ASD (HFA), and 15 typically developing (TD) peers were evaluated. Despite average cognitive functioning, the ASD group produced narratives with fewer central “gist” descriptions, more ambiguous pronominal referents, idiosyncratic language, speech dysfluency (more repetitions and self-corrections), and were less likely to name story characters. The OO participants displayed only very subtle pragmatic and higher-level language deficits (idiosyncratic language and self-correction dysfluency).

Executive functioning in individuals with a history of ASDs who have achieved optimal outcomes

Executive functioning (EF) is examined among children and adolescents once diagnosed with an autism spectrum disorder (ASD), but who no longer meet diagnostic criteria. These individuals have average social and language skills, receive minimal school support and are considered to have achieved “optimal outcomes” (OOs). Since residual impairments in these individuals might be expected in deficits central to autism, and in developmentally advanced skills, EF was examined in 34 individuals who achieved OOs, 43 individuals with high-functioning autism (HFA), and 34 typically developing (TD) peers. Groups were matched on age (M = 13.49), gender, and nonverbal IQ (NVIQ) but differed on verbal IQ (VIQ; HFA < TD, OO). On direct assessment, all three groups demonstrated average EF; however, the OO and HFA groups exhibited more impulsivity and less efficient planning and problem-solving than the TD group, and more HFA participants exhibited below average inhibition than did OO and TD participants. Parent-report measures revealed average EF among the OO and TD groups; however, the OO group exhibited more difficulty than the TD group on set-shifting and working memory. HFA participants demonstrated more difficulty on all parent-reported EF domains, with a clinical impairment in attention-shifting. Results suggest that EF in OO appears to be within the average range, even for functions that were impaired among individuals with HFA. Despite their average performance, however, the OO and TD groups differed on measures of impulsivity, set-shifting, problem-solving, working memory, and planning, suggesting that the OO group does not have the above-average EF scores of the TD group despite their high-average IQs.

Language and Verbal Memory in Individuals with a History of Autism Spectrum Disorders Who Have Achieved Optimal Outcomes

Some individuals who lose their autism spectrum disorder diagnosis may continue to display subtle weaknesses in language. We examined language and verbal memory in 44 individuals with high-functioning autism (HFA), 34 individuals with “optimal outcomes” (OO) and 34 individuals with typical development (TD). The OO group scored in the average range or above on all measures and showed few differences from the TD group. The HFA group performed within the average range but showed significantly lower mean performance than the other groups on multiple language measures, even when controlling for verbal IQ. Results also indicate that OO individuals show strong language abilities in all areas tested, but that their language may show greater reliance on verbal memory.

Social Function and Communication in Optimal Outcome Children and Adolescents with an Autism History on Structured Test Measures

Youth who lose their ASD diagnosis may have subtle social and communication difficulties. We examined social and communication functioning in 44 high-functioning autism (HFA), 34 optimal outcome (OO) and 34 typically developing (TD) youth. Results indicated that OO participants had no autism communication symptoms, no pragmatic language deficits, and were judged as likable as TD peers. Some group differences were found: OO youth had less insight into social relationships and poorer friendship descriptions than TD youth. OO participants had attention, self-control, and immaturity difficulties that may impact social abilities. However, OO participants were most engaged, friendliest, warmest, and most approachable. Overall, OO participants had no social and communicative impairments, although some exhibited mild social difficulties that often accompany attentional problems.