Identification and Diagnosis of Autism Spectrum Disorders: An Update

Greg Pasco


Pediatr Health. 2010;4(1):107-114. 

In This Article

Guidelines for Screening, Assessment & Diagnostic Practice

Diagnostic practice varies considerably between individual professionals, between different professions, between the different settings in which diagnoses are made and between different geographical areas and countries. The National Autism Plan for Children (NAP-C)[25] is a voluntary framework containing guidelines and recommendations for good practice in the identification and diagnosis of children with ASDs in the UK. The NAP-C suggests that in most cases parents will raise concerns about their child's development to a family doctor or an early years practitioner, which may then lead to a referral to a community pediatrician or speech and language therapist. If these professionals have concerns that the child's difficulties relate to autism, it is recommended that a referral is made to a specialist multiagency team for a comprehensive differential diagnostic assessment. The essential components for a multiagency assessment suggested in the NAP-C are listed in Box 2.

Guidelines for good practice in the identification, assessment and diagnosis of ASD have been developed in a number of countries including the USA,[101] Australia,[26] New Zealand[27] and Scotland.[102] These guidelines have certain recommendations in common, including improved training amongst early years professionals to enhance surveillance, minimum waiting times from referral to diagnostic assessment, multidisciplinary assessment by professionals with expertise in autism and that diagnosis must be followed by intervention for both children and their families.

The early identification of children at risk for ASDs has a number of potential important benefits, including: earlier diagnosis; earlier access to information regarding intervention and support for parents; earlier access to targeted social, communication and behavioral interventions; and earlier identification of comorbid medical, developmental and psychiatric conditions.[3] The Checklist for Autism in Toddlers (CHAT)[28] was one of the first assessments developed to screen for autism in preschoolers and was designed to be administered at routine developmental assessment at 18 months of age. The CHAT was found to have good specificity but poor sensitivity, resulting in an unacceptable number of missed cases. It is not considered to be appropriate for use as a whole-population screening instrument.[102]

A number of screening questionnaires, some based on the CHAT, have been developed subsequently and evaluated for use in both a whole-population setting and as secondary assessments following referral for developmental concern.[29–34] None of these screening instruments have yet been demonstrated to be sufficiently accurate in identifying children at risk for autism. Consequently, the UK National Screening Committee[103] does not currently recommend universal screening for autism. In the USA, however, screening of all children for autism at 'well-child' check-ups is recommended.[101,103] The two most promising screening tools currently are the Modified CHAT (M-CHAT) and the Social Communication Questionnaire (SCQ). The M-CHAT has good sensitivity when combined with a follow-up telephone interview, and further validation studies aimed at refining the items in order to develop a single parent-administered version are ongoing.[32] The SCQ is a parent questionnaire with items based on questions from the ADI-R. The SCQ may function reasonably well as a screening tool for children up to 16 years of age and when combined with an ADOS assessment it may serve as an adequate replacement for the ADI-R.[18] Various expert guidelines support the expansion of ASD-specific training for all key professionals working with preschool and school-age children, in order to enhance surveillance programs, as well as the use of autism-specific screening instruments following parental concerns about their child's development.[25,102]


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