Resource (1) is a systematic review of the evidence for the usefulness of screening for autism spectrum disorder prepared for the U.S. Preventive Services Task Force. The following is from Chapter 1 Introduction:
The Centers for Disease Control and Prevention (CDC) estimates that one in every 68 children has an autism spectrum disorder (ASD). Most are diagnosed at or after age 4. Some children are identified early for evaluation and diagnosis, either because of parental concern or through general developmental surveillance by primary care providers. In addition to this subgroup, the screening population for primary care includes other children whose families and providers do not yet have concerns. An estimated 42 to 55 percent of pediatricians regularly screen for ASD in toddlers, 2 with providers less likely to screen toddlers from under-represented ethnic and language groups (e.g., 29% of primary care pediatricians report offering Spanish ASD screening in populations of children whose parents are native Spanish speakers).3 Current approaches that include pediatric surveillance, general developmental screening, and a reliance on parents to raise concerns do not identify most children with ASD prior to age 4. The question of whether it is beneficial to do so is a component of this review.
ASD is defined in terms of persistent, significant impairments in social interaction and communication as well as restrictive, repetitive behaviors and activities. 4 Social communication and social interaction features include deficits in social-emotional reciprocity (e.g., deficits in joint attention, atypical social approach and response, conversational challenges, reduced sharing of interest, emotions, and affect), deficits in nonverbal communication (e.g., atypical eye contact, reduced gesture use, limited use of facial expressions in social interactions, challenges understanding nonverbal communication), and deficits in forming and maintaining relationships (e.g., diminished peer interest, challenges joining in play, difficulties adjusting behavior to social context). ASD features of restricted, repetitive patterns of behavior, interests, or activities may include stereotyped motor mannerisms, use of objects, or speech (e.g., simple motor stereotypies, repetitive play, echolalia, and formal or idiosyncratic speech); insistence on sameness, inflexible adherence to routines, or ritualized patterns of behavior (e.g., distress at small changes, rigid patterns of thought and behavior, performance of everyday activities in ritualistic manner); intense preoccupation with specific interests (e.g., strong attachment to objects, circumscribed or perseverative topics of interest); and sensory sensitivities or interests (e.g., hyper- or hyporeactivity to pain and sensory input, sensitivity to noise, visual fascination with objects or movement).5-7 These symptoms cause impairment across many areas of functioning and are present early in life. However, impairments may not be fully evident until environmental demands exceed children’s capacity. They also may be masked by learned compensatory strategies later in life. Many children with ASD also have intellectual impairment or language impairment, and the disorder has been associated with known medical, genetic, or environmental factors.
The Centers For Disease Control (CDC) has some excellent resources on infant and child growth and development.
Resource (2) is the CDC’s Home Page for Autism Spectrum Disorder (ASD). There are many outstanding resources on ASD for parents and healthcare professionals.
Here are some excerpts from Resource (3) from the CDC on screening and diagnosis for ASD:
Diagnosing autism spectrum disorder (ASD) can be difficult, since there is no medical test, like a blood test, to diagnose the disorders. Doctors look at the child’s behavior and development to make a diagnosis.
ASD can sometimes be detected at 18 months or younger. By age 2, a diagnosis by an experienced professional can be considered very reliable. However, many children do not receive a final diagnosis until much older. This delay means that children with an ASD might not get the help they need.
Diagnosing an ASD takes two steps:
- Developmental Screening
- Comprehensive Diagnostic Evaluation
Developmental screening is a short test to tell if children are learning basic skills when they should, or if they might have delays. During developmental screening the doctor might ask the parent some questions or talk and play with the child during an exam to see how she learns, speaks, behaves, and moves. A delay in any of these areas could be a sign of a problem.
All children should be screened for developmental delays and disabilities during regular well-child doctor visits at:
- 9 months
- 18 months
- 24 or 30 months
- Additional screening might be needed if a child is at high risk for developmental problems due to preterm birth, low birth weight or other reasons.
In addition, all children should be screened specifically for ASD during regular well-child doctor visits at:
- 18 months
- 24 months
- Additional screening might be needed if a child is at high risk for ASD (e.g., having a sister, brother or other family member with an ASD) or if behaviors sometimes associated with ASD are present
It is important for doctors to screen all children for developmental delays, but especially to monitor those who are at a higher risk for developmental problems due to preterm birth, low birth weight, or having a brother or sister with an ASD.
If your child’s doctor does not routinely check your child with this type of developmental screening test, ask that it be done.
If the doctor sees any signs of a problem, a comprehensive diagnostic evaluation is needed.
Comprehensive Diagnostic Evaluation
The second step of diagnosis is a comprehensive evaluation. This thorough review may include looking at the child’s behavior and development and interviewing the parents. It may also include a hearing and vision screening, genetic testing, neurological testing, and other medical testing.
In some cases, the primary care doctor might choose to refer the child and family to a specialist for further assessment and diagnosis. Specialists who can do this type of evaluation include:
- Developmental Pediatricians (doctors who have special training in child development and children with special needs)
- Child Neurologists (doctors who work on the brain, spine, and nerves)
- Child Psychologists or Psychiatrists (doctors who know about the human mind)
(1) Screening for Autism Spectrum Disorder in Young Children: A Systematic Evidence Review for the U.S. Preventive Services Task Force [Internet] [PubMed Abstract] [Full Text HTML] [Full Text PDF]. AHRQ Publication No. 13-05185-EF-1 February 2016. Prepared by: Vanderbilt Evidence-based Practice Center, Vanderbilt University Medical Center, Nashville, TN.