References

by Diana L. Robins et al.

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 = 16071) 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.

by Diana L. Robins

OBJECTIVE: The need for autism-specific screening during pediatric well-child visits has been established. However, additional support for specific screening instruments is needed. The current study used the Modified Checklist for Autism in Toddlers (M-CHAT) and the M-CHAT Follow-Up Interview to screen 4,797 children during toddler checkups. Of the 4,797 cases, 466 screened positive on the M-CHAT; of the 362 who completed the follow-up interview, 61 continued to show risk for autism spectrum disorders (ASDs). A total of 41 children have been evaluated; 21 children have been diagnosed with ASD, 17 were classified with non-ASD delays, and three were typically developing. The PPV of M-CHAT plus interview was .57. It is notable that only four of the 21 cases of ASD were flagged by their pediatrician. These findings suggest that the M-CHAT is effective in identifying ASD in primary care settings. Future research will follow this sample longitudinally.

by C.DiGuiseppi et al.

OBJECTIVE: We assessed the prevalence of autism spectrum disorders (ASD) and screening test characteristics in children with Down syndrome.

METHOD: Eligible children born in a defined geographic area between January 1, 1996, and December 31, 2003, were recruited through a population-based birth defects registry and community outreach, then screened with the modified checklist for autism in toddlers or social communication questionnaire, as appropriate. Screen-positive children and a random sample of screen-negative children underwent developmental evaluation.

RESULTS: We screened 123 children (27.8% of the birth cohort). Mean age was 73.4 months (range, 31-142). Compared to screen-negative children, screen-positive children had similar sociodemographic characteristics but a lower mean developmental quotient (mean difference: 11.0; 95% confidence interval: 4.8-17.3). Weighted prevalences of autistic disorder and total ASD were 6.4% (95% confidence interval [CI]: 2.6%-11.6%) and 18.2% (95% CI: 9.7%-26.8%), respectively. The estimated minimum ASD prevalence, accounting for unscreened children, is 5.1% (95% CI: 3.3%-7.4%). ASD prevalence increased with greater cognitive impairment. Screening test sensitivity was 87.5% (95% CI: 66.6%-97.7%); specificity was 49.9% (95% CI: 37.0%-61.4%).

CONCLUSION: The prevalence of ASD among children with Down syndrome aged 2 to 11 years is substantially higher than in the general population. The modified checklist for autism in toddlers and social communication questionnaire were highly sensitive in children with Down syndrome but could result in many false positive tests if universal screening were implemented using current algorithms. Research needs include development of specific ASD screening algorithms and improved diagnostic discrimination in children with Down syndrome. Timely identification of these co-occurring diagnoses is essential so appropriate interventions can be provided.

by Diana L. Robins et al.

OBJECTIVE: Early intervention for autism spectrum disorders necessitates early detection. This need has led to widespread agreement across disciplines that screening is critical in very young children. Two screening issues are highlighted in this review. Level of screening refers to the type of sample: Level I is defined as an unselected sample, and Level II consists of selected children already identified as being at risk for a developmental disorder. Breadth or scope of screening refers to the range of difficulties the screening tool attempts to identify: broad screening instruments identify multiple range of developmental difficulties, whereas disorder-specific tools focus on a single disorder or class of disorders. Broad developmental instruments reviewed include the Parents' Evaluation of Developmental Status and the Ages and Stages Questionnaires; autism-specific tools reviewed include the Checklist for Autism in Toddlers, the Modified Checklist for Autism in Toddlers (M-CHAT), the Pervasive Developmental Disorders Screening Test, Second Edition, and the Screening Tool for Autism in Two-year-olds. The development of the M-CHAT, a Level I and Level II screening instrument, is described, and current research and clinical use of the M-CHAT are reviewed, including description of the structured follow-up interview which reduces the false-positive rate of the parent-report M-CHAT.

by H. Perera et al.

OBJECTIVE: All children aged 18-24 months in a defined geographical area were initially screened for autism, using 'Red Flag' criteria. All the children with one or more positive 'Red Flag' signs were further screened using Modified Checklist for Autism in Toddlers (M-CHAT) translated to Sinhala, followed by a comprehensive clinical assessment. Of a sample of 374 children, 'Red Flag' signs were positive in 28 (7.4%). Four children received a diagnosis of autism on clinical assessment giving a prevalence of 1.07% or 1 per 93 in the 18-24-month age group. Sensitivity of M-CHAT was only 25%, and specificity 70%. The high prevalence detected strongly justifies early community-based screening, but a culturally sensitive screening tool needs to be developed for Sri Lanka.

by K.C. Kuban et al.

OBJECTIVE: To test the hypothesis that children born preterm are more likely to screen positive on the M-CHAT for an autism spectrum disorder.

STUDY DESIGN: We compared the M-CHAT positive rate of those with cerebral palsy, cognitive impairment, and vision and hearing impairments to those without such deficits.

RESULTS: Relative to children who could walk, the odds for screening positive on the M-CHAT were increased 23-fold for those unable to sit or stand independently and more than 7-fold for those requiring assistance to walk. Compared with children without a diagnosis of cerebral palsy, those with quadriparesis were 13 times more likely to screen positive, and those with hemiparesis were 4 times more likely to screen positive. Children with major vision or hearing impairments were 8 times more likely to screen positive than those without such impairments. Relative to those with a Mental Development Index (MDI) of greater than 70, the odds for screening positive were increased 13-fold for those with an MDI of less than 55 and more than 4-fold for those with an MDI of 55 to 69.

CONCLUSIONS: Major motor, cognitive, visual, and hearing impairments appear to account for more than half of the positive M-CHAT screens in extremely low gestational age newborns. Even after those with such impairments were eliminated, 10% of children--nearly double the expected rate--screened positive.

by A.V. Snow et al.

OBJECTIVE: This study assessed the psychometric properties of the Modified Checklist for Autism in Toddlers (M-CHAT) and the Social Communication Questionnaire (SCQ) in a sample of preschool children referred for possible pervasive developmental disorders (PDDs). The sample consisted of 82 children between the ages of 18 and 70 months (54 with a PDD diagnosis and 28 with non-PDD diagnoses). M-CHAT scores were analyzed for 56 children aged 18-48 months old and SCQ scores were analyzed for 65 children aged 30-70 months old. Optimal sensitivity and specificity were achieved using the cutoff score of any three items on the M-CHAT and lowering the cutoff score of the SCQ. The diagnostic agreement of both instruments was also compared in an overlapping subsample of 39 children aged 30-48 months. Overall, the M-CHAT and SCQ appear to more accurately classify children with PDDs who have lower intellectual and adaptive functioning.

by J.A. Pinto-Martin et al.

OBJECTIVE: This study compared the number of children identified at risk for ASD at their well child visits between the ages of 18 and 30 months using a general developmental screening tool and an autism-specific screening tool.

METHODS: The Parents' Evaluation of Developmental Status (PEDS) was used as the general developmental screening tool and the Modified Checklist for Autism in Toddlers (M-CHAT) was used as the autism-specific tool. These tools were administered concurrently to 152 children.

RESULTS: Cross tabulations and chi tests were used to determine the utility of the PEDS as the first step of a two-part screen for ASD. Of those who screened positive for developmental concerns on the PEDS (n = 38), 16% screened positive for ASD on the M-CHAT; of those who did not screen positive for developmental concerns on the PEDS (n = 114), 14% screened positive for ASD on the M-CHAT (p = .79).

CONCLUSION: The PEDS missed the majority of children who screened positive for ASD on the M-CHAT, suggesting that these two tools tap into very different domains of developmental concerns. The findings support the use of an ASD-specific tool for all children in conjunction with regular standardized developmental screening.

by R.L. Stilp et al.

OBJECTIVE: Twin and family studies of autistic traits and of cases diagnosed with autism suggest high heritability; however, the heritability of autistic traits in toddlers has not been investigated. Therefore, this study's goals were (1) to screen a statewide twin population using items similar to the six critical social and communication items widely used for autism screening in toddlers (Modified Checklist for Autism in Toddlers); (2) to assess the endorsement rates of these items in a general population; and (3) to determine their heritability.

METHOD: Participants composed a statewide, unselected twin population. Screening items were administered to mothers of 1,211 pairs of twins between 2 and 3 years of age. Twin similarity was calculated via concordance rates and tetrachoric and intraclass correlations, and the contribution of genetic and environmental factors was estimated with single-threshold ordinal models.

RESULTS: The population-based twin sample generated endorsement rates on the analogs of the six critical items similar to those reported by the scale's authors, which they used to determine an autism threshold. Current twin similarity and model-fitting analyses also used this threshold. Casewise concordance rates for monozygotic (43%) and dizygotic (20%) twins suggested moderate heritability of these early autism indicators in the general population. Variance component estimates from model-fitting also suggested moderate heritability of categorical scores.

CONCLUSIONS: Autism screener scores are moderately heritable in 2 to 3-year-old twin children from a population-based twin panel. Inferences about sex differences are limited by the scarcity of females who scored above the threshold on the toddler-age screener.

by Juhi Pandey et al.

OBJECTIVE: 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.

by Jamie M. Kleinman et al.

OBJECTIVE: Autism spectrum disorders (ASD) often go undetected in toddlers. The Modified Checklist for Autism in Toddlers (M-CHAT) was used to screen 3,793 children aged 16-30 months from low and high-risk sources; screen positive cases were diagnostically evaluated. Rescreening was performed on 1,416 children aged 42-54 months. Time1 Positive Predictive Value (PPV) was .36 for the initial screening and .74 for the screening plus follow-up telephone interview; values were similar for Time2 PPV. When separating referral sources, PPV was low for the low-risk sample but acceptable with the follow-up telephone interview. Children with ASD from the low-risk and high-risk samples were highly similar. Results indicate that the M-CHAT continues to be a promising instrument for the early detection of ASD.

by J.L. Matson et al.

OBJECTIVE: A top priority in the field of autism spectrum disorders (ASD) is the development of precise early diagnostic tools that can be completed with minimal time and training. We report on the convergent and divergent validity of the Baby and Infant Screen for Children with aUtIsm Traits (BISCUIT), specifically the BISCUIT-Part 1. Previous research with this scale has determined its reliability and sensitivity/specificity. In this study, a sample of 1,007 toddlers 17-37 months of age were assessed individually. The BISCUIT-Part 1 demonstrated good convergent validity with the Modified CHecklist for Autism in Toddlers (M-CHAT) and the Personal Social domain from the Battelle Developmental Inventory, Second Edition (BDI-2). Additionally, divergent validity was demonstrated by its small correlation with the Adaptive and Motor domains from the BDI-2.