New tool helps primary care physicians diagnose autism early
- Copyright © 2004 by the American Academy of Pediatrics
A primary care physician caring for approximately 1,000 children in a general practice should expect that approximately three to seven of his/her patients will demonstrate signs of autism spectrum disorder (ASD).
ASD appears to be more common than once thought. The reason for this is not yet clear but probably relates to a number of factors, including broader criteria, increasing professional and public awareness of the symptom spectrum, better ascertainment and perhaps a true rise in prevalence. Sufficient evidence now suggests that vaccines and thimerosal are not likely responsible for the apparent rise in prevalence.
Why is early diagnosis important?
A number of consensus publications, supported by research, have documented the positive benefit of early intervention, particularly when it is initiated prior to 3 years of age. The goal of these documents was to raise awareness of the very early signs of ASD so children might be diagnosed and referred to intervention earlier.
Currently, the average age of diagnosis is approximately 3 years. However, the signs of ASD are present in most children prior to 18 months of age. Some children with ASD appear to be “normal” until 12 to 24 months of age and then regress. However, retrospective assessments of home videos at the child’s first birthday often reveal subtle abnormalities, especially failure to orient to one’s name. A multicenter study is in progress (“Baby Sibs Project”) that is attempting to identify very early signs of ASD (those appearing between the ages of 3 and 6 months) in infants who are younger siblings of children already diagnosed with ASD.
How does one make an early diagnosis?
Parents are now more aware of ASD symptoms due to extensive coverage of ASD in the media. Thus, they are more likely to raise concerns about the possibility of ASD. The first thing the primary physician can do is to listen to the parents and take their concerns seriously.
The most common parental concern is “delayed speech.” However, speech delays usually are not recognized until after the second birthday. An earlier, but less commonly expressed concern, is that of a hearing impairment. The apparent hearing deficit is atypical in that symptoms are inconsistent, i.e., although the child does not respond to his/her name being called or to verbal commands, he/she seems to hear environmental sounds well.
Finally, parents may state that the child does not seem to notice when they enter or leave the room, there is little or no eye contact or the child seems to be in his/her own world.
Impairment in joint attention skills are among the earliest signs of ASD and are now known to be unique to and almost universal in children with ASD. However, due to lack of familiarity, parents are less likely to have concerns regarding deficits in this continuum of social-communicative development. Joint attention behaviors involve the triadic coordination or sharing of attention among the infant, another person and an object or event. Joint attention skills typically emerge between 6 and 14 months and include following a caregiver’s gaze, following a point, showing and pointing. Joint attention impairments do not cause autism; rather they are manifestations of abnormalities of early brain development, most likely in the amygdala.
Most ASD screening tools assess joint attention skills. The primary pediatrician is encouraged to become familiar with at least one screening tool and administer it to all children at 18 months of age, especially those with suspected language and/or social skills deficits. (For a discussion of tools, see the AAP technical report: Pediatrics. 2001;107:e85OpenUrl, or the American Academy of Neurology (AAN) practice parameters: Filipek PA, et al. Neurology. 2000;55:468-479OpenUrl; Filipek PA, et al. J Autism Dev Disord. 1999; 29:439-484OpenUrlCrossRefPubMedWeb of Science). Most of these tools are short questionnaires that parents can complete in a waiting room. Additionally, all younger siblings of children with ASD should be monitored vigilantly as these children are at much higher risk (5% to 7%) for developing ASD.
When there is parent and/or physician concern based on history, observation and/or a positive screening questionnaire, the physician should immediately refer the family to a specialist, or preferably, a team of specialists experienced in the diagnosis of ASD. At the same time, the child should be referred to the local intervention program. A definitive diagnosis of autism is not necessary to meet eligibility criteria for these services.
A review of the literature revealed that effective programs address communication and social skills, incorporate behavior management strategies that are based on a functional analysis of behavior, maintain a high level of parent involvement, and are structured, generalizable and intense (15 to 20 hours per week).
Unfortunately, intense programs usually are not available for children younger than 3 years of age. Nevertheless, all programs should incorporate curricula that promote joint attention skill development (Walen J. Child Psychol Psychiatry. 2003;44:456OpenUrl). Joint attention skills play a “pivotal” role in later communication and social development, i.e., they are the skills upon which progress depends.
In an effort to facilitate the implementation of the AAP policy statement and AAN practice parameters recommendations regarding early diagnosis, the Academy assembled an Autism Expert Panel to evaluate strategies and to develop helpful tools. The first tool is included as an insert in this issue of AAP News. See A.L.A.R.M.: Autism is prevalent; Listen to the parents; Act early; Refer; Monitor. Others tools are under consideration or in development.
Dr. Johnson is a member of the AAP Committee on Children with Disabilities and co-chair of the AAP Autism Expert Panel.