Screening for early signs of autism spectrum disorder (ASD) (before 36 months of age) allows an early diagnosis and early intervention programs that provide better developmental opportunities for the child. The objective of this chapter is to increase the knowledge about early signs of ASD enabling their early detection. The method used was a literature review of the early warning signs of autism spectrum disorder in children between 24 and 36 months of age in the domains that characterize this disorder.
TopBackground
Earlier an educator, researcher and practitioner Kanner (1943) provided an overarching clinical description and defined the Syndrome of Infantile Autism. Currently, ASD is considered a complex neurodevelopmental disorder characterized by deficits in social communication and social interaction across multiple contexts, and restricted, repetitive patterns of behavior, interests, or activities. The term spectrum refers to a wide range of symptoms that vary greatly depending on the severity of the autistic condition, developmental level, and chronological age (APA, 2013). Furthermore, there are many medical and psychiatric comorbidities associated with this disorder, and it is not uncommon for individuals with ASD to have Attention Deficit Hyperactivity Disorder (ADHD), anxiety, and mood disorders (Mazzone et al., 2012; Simonoff et al., 2008). It is also estimated a 70% prevalence of intellectual disability (Marchezan & Riesgo, 2016).
ASD is not degenerative (APA, 2013), and appropriate early intervention programs (before 36 months of age) can change a child's developmental path and improve outcomes (Rogers & Dawson, 2010; Rogers & Vismara, 2014). During the first years of life, the human brain is prepared to develop social and language skills, which are the main areas of difficulty in individuals with ASD (Franz & Dawson, 2019). Due to a period of maximum brain plasticity (Belsky, 2010), early intervention provides the opportunity to maximize the child's learning, thereby preventing the negative side effects of the disorder and improving their functional skills and quality of life (Rogers & Dawson, 2010; Rogers & Vismara, 2014).
The prevalence of ASD is high worldwide (Elsabbagh et al., 2012; Maenner et al., 2020; Özerk, 2016), which has intensified the demand for therapeutic and educational services (Steinbrenner et al., 2020). A study carried out in Norway found a much higher increase in prevalence rate among preschool-age (1-5 years) children than school age (6-16 years) children (Özerk et al., 2020). According to the National Center for Education Statistics from the United States Department of Education (2020), in 2018-19, the number of students ages 3-21 who received special education services under the Individuals with Disabilities Education Act (IDEA, 2004) was 7.1 million, or 14 percent of all public school students. Among students receiving special education services, 11 percent had ASD diagnosis.
There are a set of practices that have scientific evidence of positive effects with autistic children, and most of them can be implemented with children under 36 months of age to improve different skills, including school readiness (Steinbrenner et al., 2020). Nevertheless, many children do not have access to these programs because of late diagnosis, especially the milder cases when the symptoms are less severe (Au et al., 2020; Brett et al., 2016; Gomes et al., 2015). Families usually face a long journey during their search for a diagnosis (Zwaigenbaum & Maguire, 2019).