DIAGNOSIS AND ASSESSMENT

Autism, or autism spectrum disorder (ASD), first described in 1943 (Kanner, 1943), is a neurodevelopmental disorder characterized by impairments in social interaction and communication, along with repetitive or stereotyped patterns of behaviors and often restricted interests.

The diagnosis of ASD is typically made during childhood, based on comprehensive behavioral evaluations by specialists in child psychiatry or psychology or by those in behavioral and developmental pediatrics. ASD was not officially recognized until DSM-III, the third edition of the Diagnostic and Statistical Manual of Mental Disorders, in 1980 (APA, 1980; Kanner, 1943). The current version of the DSM introduced in 2013, DSM-5, is the first edition of the DSM to use the term “autism spectrum disorder.” This version does not distinguish subtypes such as “autistic disorder” or “Asperger syndrome,” and the diagnostic criteria specified in the DSM-5 for ASD are somewhat narrower than used previously. DSM-5 criteria require that a child has persistent impairment in social communications and interactions across multiple contexts as well as restricted or repetitive patterns of behavior, interests, or activities; that symptoms should present in early childhood and cause significant functional impairments; and that the impairments are not better explained by intellectual disability (APA, 2013).

DSM-5 introduced major change by eliminating subcategories and providing an overall approach to the diagnosis of ASD (Volkmar et al., 2014a). Concerns about individuals losing services prompted the addition of a “grandfather clause” in DSM-5 granting continued diagnostic assignment to cases previously diagnosed under DSM-IV.

Although experienced clinicians can diagnose ASD by the age of 2 years in many affected children, and while the diagnosis of ASD can usually be made very clearly by age 3, population-based studies in the United States have shown the median age at first diagnosis of ASD to be older than 5 years (Maenner et al., 2013; Shattuck et al., 2009). The process of obtaining a diagnosis of ASD often requires a referral from a pediatrician or other primary care provider to a clinical center or care provider experienced in ASD diagnosis. Once a referral has been made, families can face wait times of 6 to 12 months or longer for the first available appointment. At each step of the diagnostic process, financial and cultural barriers can delay the identification of ASD, especially for socioeconomically disadvantaged children (Magaña et al., 2013).

Several sets of practice guidelines are now available to provide guidance on screening and diagnosis (McClure, 2014). Current practice guidelines suggest that there should be a comprehensive assessment involving structured observations of the child's behavior; extensive parental interviews; testing of cognition, speech and language, hearing, vision, and motor function; a physical examination; and a collection of medical and family history information (Millward et al., 2008; Nye and Brice, 2005; Reichow et al., 2010, 2013). The assessment may also involve genetic testing, neuroimaging, or other studies.

Early screening is recommended beginning at 18 months and during the preschool years. In general, ASD is an early-onset disorder, but early screening may miss a minority of cases where parents report regression after some period of normal development; in other instances symptoms may be missed on early screening in more cognitively able children. Early diagnosis and assessment are important to optimize the potential for a good outcome (McClure and Melville, 2007; Volkmar et al., 2014a). A family history of ASD (e.g., in a sibling) should prompt higher levels of clinical concern.

Clinical evaluation is indicated to look for symptoms and signs of associated conditions (notably seizure disorder or epilepsy). Although sometimes associated with single-gene conditions (notably fragile X and tuberous sclerosis), the genetics of ASD appears to be very complex, with potentially many different genetic pathways being associated with ASD (Geschwind, 2011). The role of genetic factors in etiology has been increasingly recognized in recent years, although genetic testing remains limited, apart from certain well-recognized single-gene conditions. More extensive genetic testing may be indicated based on clinical presentation or family history. Guidelines for genetic testing are now available (Schaefer et al., 2013).

A range of tests are used to assess developmental levels and the need for occupational and physical therapy. A number of screening and diagnostic instruments are available (see Volkmar et al., 2014a). It is common for the assessment of cognition and communication to reveal multiple areas of difficulty. Unusual styles of learning in ASD lead to problems in generalization, which can cause difficulty with adaptive skills. Therefore, the ability to apply knowledge to real-world settings should be assessed.

DEMOGRAPHIC FACTORS AND DURATION OF THE DISORDER

COMORBIDITIES

Issues of comorbidity are complex, particularly in individuals without spoken language (Matson and Nebel-Schwalm, 2006). One thing that is clear, however, is that ASD is associated with an increased risk of intellectual disability (Simonoff et al., 2008; White et al., 2009). Furthermore, epilepsy co-occurs with as many as 20 percent of cases, with peak periods of onset in both early childhood and adolescence (Volkmar et al., 2014b). It remains unclear whether the poor outcomes are the result of a common underlying cause for both epilepsy and ASD or the result of side effects from anticonvulsant treatments (Howlin et al., 2014). For school-age children with ASD, attentional difficulties and irritability are relatively common (Volkmar et al., 2014a). By adolescence, particularly for more cognitively able individuals, the risk for mood disorders (particularly depression) and anxiety-related problems increases. The association of ASD with anxiety and mood problems in older individuals appears to be relatively strong.

In younger children, ASD raises the risk for nonfatal and fatal injuries to double the rates in the general population. Bolting (running away) is a frequent problem and cause of injury or death. Having ASD at least doubles the risk of being bullied, which can exacerbate other issues such as anxiety and depression (Cappadocia et al., 2011). In the past, there was a strong co-occurrence of ASD and intellectual disability (ID). While early diagnosis and intervention has decreased this association, a minority of patients still have co-occurring diagnoses of ASD and ID. Given that ASD is a disorder involving communication, it is unusual (but not impossible) for a child with ASD to exhibit comorbid language conditions.

FUNCTIONAL IMPAIRMENT

Functional (adaptive) skills are invariably impaired in ASD and are an important impediment to adult self-sufficiency (Paul et al., 2004). These functional impairments are typically highlighted in practice guidelines as a major focus of intervention (McClure, 2014; Volkmar et al., 2014a). Deficits may be severe and persistent and result from problems in the overall learning style associated with ASD as well as from difficulties in generalization. Functional impairments stem from the basic and fundamental deficits in social interest and motivation that causes problems with learning, organization, multitasking, and generalization (executive functions). These difficulties in organizational and executive function lead to major problems in dealing with new situations as well as with situations that require the generalization of knowledge across settings. Even for the most cognitively able individuals with ASD, problems with the generalization of knowledge into real-life situations are a source of considerable impairment, and deficits in functional skills have frequently been included as a defining feature of the condition (Klin et al., 2007).

A number of excellent assessment instruments of adaptive and functional skills are available and have consistently documented deficits in multiple areas of functioning, such as social skills, communication, and activities of daily living (Goldstein et al., 2009). In spite of the availability of assessment instruments, the severity of impairment in autism remains complex, because expressions of the syndrome change with age, particularly in early childhood and in adolescence, where some individuals make major gains while others lose skills. Furthermore, no single convention exists for classification of difference in ability levels or severity of impairment. For example, the terms “high functioning” or “low functioning” are frequently used, but primarily refer only to cognitive ability or IQ. In reality, many individuals with high IQ have severe impairment in adaptive skills. For example, an individual may have an IQ above 140, but the social skills of a 4-year-old child (Klin et al., 2007). Further complicating the assessment of severity is that major differences in various sub-indices of IQ can exist, with differences up to 70 points (Volkmar et al., 2005). As a practical matter, the severity of impairment in multiple areas, regardless of IQ, is the major source of disability.

TREATMENT AND OUTCOMES

Early approaches to treatment in ASD focused on psychotherapy, but over time it became apparent that children with ASD were more likely to improve with structured, special education interventions (Bartak et al., 1977). Other important contributions to more effective treatment included the advent of the Education for All Handicapped Children Act, which mandated education as a right for children with special needs, including those with ASD (NRC, 2001), and the official recognition of ASD in 1980. The early interest in behavioral approaches has now expanded into the field of applied behavior analysis, which has repeatedly been shown to be an effective evidence-based approach (Smith, 2010). A review by the National Research Council on early intervention for ASD reported a range of programs and models, each of which had some empirical support; the literature on evidence-based treatments has not increased substantially in subsequent years (NRC, 2001).

A number of meta-analyses and reviews of the available treatment literature are now available (Reichow et al., 2010). It is important to note that the treatment literature is of variable quality and that noteworthy gaps remain. However, this literature has been increasingly included in the various official guidelines for practice (McClure, 2014).

Comprehensive treatment programs fall into four types. One group of treatment programs employs a developmental approach, notably the Rogers “Denver” model and the less-well-researched Greenspan “Floortime” approach (Greenspan et al., 2008; Rogers et al., 2012). A second group of treatment programs is more behaviorally focused and includes most of the programs employing applied behavior analysis (Smith et al., 2007). A third group of treatment programs is exemplified by the state-wide TEACCH model used in North Carolina, which is more eclectic in nature (Schopler et al., 1995). A fourth group of treatment programs uses a combination of behavioral and developmental approaches, as exemplified by pivotal response therapy (Koegel and Koegel, 2006).

Generally, the goal of all treatment programs is to minimize the disruptive effects of ASD on learning, while maximizing more normative processes. Treatment goals change with age and developmental level but typically include a focus on social, language, and adaptive (self-help) skills. Educational and behavioral treatments draw on the expertise of a range of professionals. Specialists in communication focus on expanding the range of the child's communicative ability beyond vocabulary. Children who lack verbal language can be helped through augmentative strategies (e.g., manual signing, picture exchange, and new computer-based technologies). Behavioral techniques help with management of disruptive behavior and facilitate learning. Given the unusual learning style of children with ASD, a focus on the generalization of skills into functional activities is important. Social skills teaching is an important aspect of treatment programs (Reichow et al., 2012).

Pharmacological interventions may be very helpful with behavioral problems and comorbid conditions, but they do not affect the central social and communicative aspects of ASD. The newer atypical neuroleptics can help with the management of agitation and stereotypic behaviors, and other agents can help with issues of mood, anxiety, and attention (Volkmar et al., 2014a); however, side effects of medication sometimes limit their usefulness (McDougle et al., 2005). For more cognitively able individuals, medication use can be combined with supportive psychotherapy, and several models of treatment are available (Scarpa et al., 2013).

A number of studies, including independent meta-analyses, have been conducted of treatment effects in ASD. The available literature varies, reflecting major differences in research that arise from a large number of different professional disciplines involved in the treatment of ASD. A review of five meta-analyses by Reichow reported effect sizes for psychosocial, early intensive behavioral interventions ranging from 0.38 to 1.19 for IQ and 0.3 to 1.09 for adaptive behavior (Reichow et al., 2012). A meta-analysis of cognitive-behavioral therapy for children by Sukhodolsky and colleagues, reported effect sizes of 1.19 and 1.21 for clinician- and parent-reported outcome measures of anxiety, respectively. A review of five randomized controlled trials of social skills training reported treatment effect sizes for a number of outcomes, including an effect size of 0.47 for improved social competence and 0.41 for friendship quality (Reichow et al., 2012). Similar effect sizes have been shown for pharmacological treatments. Arnold and colleagues and McCracken and colleagues reported effect sizes of 1.2 for behavioral irritability treated with atypical neuroleptics like Risperidone. A large number of alternative/complementary treatments have been proposed for ASD and are widely used by parents (Levy and Hyman, 2015). These typically lack an empirical foundation, but it is important that service providers be aware of their use.

It is important to emphasize that, with earlier diagnosis and intervention, many (though not all) children make substantial gains. More and more individuals now seek post–high school education or vocational training, or both (Howlin et al., 2013; Vanbergeijk et al., 2008).

FINDINGS

• The diagnosis of ASD requires a comprehensive behavioral and medical evaluation by experts, including a clinical evaluation and the use of disorder-specific screening and diagnostic instruments. The role of genetic testing is limited, apart from a small number of well-characterized single-gene conditions.
• The age of onset for ASD is in early childhood. Individuals diagnosed with ASD are likely to have functional impairments throughout their lives; however, the severity of these impairments can vary greatly, from profound to relatively mild. The diagnosis of ASD can be made in most children with great certainty by age 3.
• ASD is more common in males by more than three- to fivefold.
• Unlike other mental disorders, ASD is diagnosed less often in children living in poverty, although most population studies indicate equal rates among children living in low-income households, suggesting disparities in access to early identification.
• ASD is associated with an increased risk of intellectual disability.
• Significant impairment usually persists into adolescence and adulthood.
• Early diagnosis and the application of evidence-based interventions increase the likelihood that a child will have better outcomes and reduced functional impairments. The goals of treatment are to minimize disruptive effects and to improve adaptive functioning.

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