Autism spectrum disorder: Keys to early detection and accurate diagnosis
Careful attention is required for early detection and to rule out other conditions
Screening and diagnosis
A medical workup is the first step to rule out other potential conditions that could be masquerading as ASD.17 Obtain a comprehensive history from parents/caregivers, particularly regarding social, behavioral, movement, sensory, and developmental aspects. In addition, audiologic testing is an essential step. Consider genetic testing, particularly if any dysmorphic features and/or ID are present, both of which confer additional risk for a genetic syndrome.6 A physical exam to detect any neurologic anomalies, organ dysfunction, and body dysmorphic features should be conducted.6
The Modified Checklist for Autism in Toddlers–Revised (MCHAT-R) is a commonly used, validated parental screening survey for ASD.5,6 Research has shown that this survey has <50% specificity.5A recent American Academy of Pediatrics Clinical Report recommended universal screening for ASD at pediatric visits at age 18 months and at 24 months, in addition to developmental screening for all children at routine pediatric visits at age 9, 18, and 30 months.6,19
Screening tools such as the Modified Checklist for Autism in Toddlers with Follow-Up (M-CHAT/F) can be integrated into routine primary health care. In a large (N = 25,999) study, Guthrie et al45 used M-CHAT/F to conduct universal, primary care–based screening in young children. They found that the positive predictive value of M-CHAT/F was lower among girls, children of color, and those from lower-income households. There is a need for development of screening tools with higher accuracy and sensitivity for identifying young children with ASD regardless of their ethnic or socioeconomic background, and also for children older than 30 months.5,6,45
Definitive diagnosis of ASD is ideally done by a multidisciplinary team46 using established gold standard measures such as the ADOS (Autism Diagnostic Observation Schedule) and ADI-R.47 Such multidisciplinary teams usually include a child psychiatrist, child psychologist, speech therapist, occupational therapist, school educator, and developmental pediatrician. However, because there are long wait times to receive this type of diagnosis in the United States,6 in the interest of not missing the critical window of early intervention, physicians who suspect a patient may have ASD should refer the child and family for appropriate educational and behavioral interventions as early as possible, rather than waiting for definitive testing.6
ADI-R has limitations in distinguishing ASD from other conditions, especially in very young children, and particularly in distinguishing ASD from childhood-onset schizophrenia.47 Similarly, ADOS, which is a semi-structured, standardized, observation assessment tool, also has limitations, including generating false-positive results, which can make it difficult to distinguish children and adolescents with developmental disabilities from those with ASD.47 However, in combination, these 2 tools are generally efficacious.47 Further research is warranted to develop and fine-tune definitive diagnostic tools with greater sensitivity and specificity.
A newer measure—the Autism Parent Screen for Infants (APSI) questionnaire—has been shown to be effective in detecting early signs predictive of ASD in high-risk infants (eg, siblings of children with ASD), and has potential as an early screening tool.48,49
Part 2 of this article will review nonpharmacologic and pharmacologic treatments for patients with ASD.
