Screening Assessment and Diagnosis of Autism Spectrum Disorder

By: Dr. Uma Dalvi

Autism spectrum disorder is a condition related to brain development that impact on how a person perceive and socializes with other causing problem in social interaction and communication. This disorder also includes limited and repetitive pattern of behaviour. The term ‘spectrum’ in autism spectrum disorder refers to a wide range of symptoms and severity.

It is been observed that ASD begins in early childhood, often children show systems within the first year. In small number of cases children may appear to develop normally in the first year and then go through a period of regression between 18 to 24 months of age when they develop the autism symptoms.

While there is no cure for autism spectrum disorder early screening and intensive early treatment can make a big difference in the lives of many children.

When to see a doctor:  Mostly all children develop at their own pace and many don’t follow the exact timeline too. But children with ASD usually show signs of delayed development before the age of 2years. As a parent if you are concerned of any issues related to the development of your child should immediately discuss your concern with your doctor. Developmental screening can as a primary step, can be done by a number of professional in healthcare, community and school setting which can prove very helpful to identify the high-risk children.

Screening recommendation:  Screening tool are designed to help identify children who might have developmental delays. Screening tool can be specific to a disorder (e.g.,- autism)  or an area ( ex- cognitive development, language, or gross motor skills) or they may be general, encompassing multiple areas of concerns. Some of these screening tools are primarily used in pediatric practices.

 A comprehensive ASD evaluation include a developmental history, observations, direct interaction, a parent’s interview, and an evaluation of functioning in the following areas; social communication, sensory, emotional, cognitive and adaptive behaviour.

Research has found that ASD can sometime be detected at 18 months or younger. By age of 2 a diagnosis by an experienced professional can be considered very reliable. Children should be screened for developmental delay and disabilities during regular well –child doctor visits mostly at 9months, 18 and 30 months. In addition all children should be screened specially for ASD during 18 and 24 months. Additional screening might be need is a child is at high risk (having a sibling with ASD) or if symptoms are present.

Positive screening:

• Under 18 months- infant/ toddler checklist, communication and symbolic behaviour scale development profile.
• Over 18 months – many available screeners,categorized as level 1 or level 2
• Level 1 – administered within a well visit, differentiate children at risk for ASD from typical peers. ex- MCHAT
• Level -2 administered / used in EI or developmental clinics, differentiate children at risk for ASD from other developmental disorder.

If the child is found with positive symptoms then the child should be immediately refer for comprehensive diagnostic evaluation.

Refer –

• Developmental paediatrician
• Paediatric neurologist
• Paediatric psychologist or psychiatrist
• Refer to multi-disciplinary areas (audiology, speech evaluation etc.)

Screening tool do not provide conclusive evidence of developmental delays and do not result in diagnoses. A positive screening result should be followed by a thorough assessment.

Selecting a screening tool :While selecting a developmental screening tool we should take the following into consideration:-

• Domain(s) the screening tool covers, what are the questions that need to be answered? What types of delays or conditions do you want to detect?
• Psychometric properties- these affect the overall ability of the test to do what it is meant to do.
• The sensitivity of a screening tool is the probability that it will correctly identify children who have developmental delays or disorder.
• Characteristics of the children e.g., age and presence of risk factors.
• Setting in which the screening toll will be administered.

Diagnostic Assessments tool:

There are a variety of screening and assessment tool that may be used during the assessment process to determine a diagnosis of autism spectrum disorder according to DSM -5 or ICD -10 criteria.

Selected examples of diagnostic tools :

• Autism diagnosis interview- revised (ADI-R):

A clinical diagnostic instrument for assessing autism in children and adults. The instrument focuses on behaviour in three main areas: reciprocal social interaction, communication and language and restricted and repetitive, stereotype interest and behaviour . the ADI-R is appropriate for children and adults with mental ages about 18 months and above.

• Autism Diagnostic Observation Schedule generic:

A semi – structured , standardized assessment of social interaction, communication, play and imaginative use of materials for individuals suspected of having ASD. The observation schedule consists of four 30-min modules, each designed to be administered to different individual according to their level of expressive language.

• Childhood Autism Rating scale (CARS)

            Brief assessment suitable for use with any child over 2 years of age. CARS include items drawn from five prominent systems for diagnosing autism; each         item covers a particular characteristic, ability, or behavior.

• Gilliam autism rating scale (GARS-2)

            Assists teachers, parents, and clinicians in identifying and diagnosing autism          in individuals ages 3 through 22. It also helps estimate the severity of the             child’s disorder.

• Developmental screening test
• Autism diagnostic observation schedule
• Checklist for autism in toddlers ( CHAT)
• Screening toll for autism in two-year- old ( STAT)
• Autism behaviour checklist (ABC)
• Detection of autism by infant sociability interview (DAISI)
• Vineland adaptive behaviour scale (VABS) etc…

Diagnostic Criteria

Diagnosing autism spectrum disorder (ASD) can be difficult because there is no medical test, likeblood test, to diagnose the disorder. Doctors look at the child’s developmental history,behaviourassessment, assessment of symptoms   and diagnostic test, to make a diagnosis. The medical diagnosis is made by the physician according to the diagnostic and statistic manual (DSM-5)

The American Psychiatric Association’s Diagnostic and Statistical Manual, Fifth Edition (DSM-5)  provides standardized criteria to help diagnose ASD.

DSM-5 Autism Diagnostic Criteria

A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history.

• Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
• Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
• Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in  sharing imaginative play or in making friends; to absence of interest in peers.
• B. Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history.
• Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
• Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat food every day).
• Highly restricted, fixated interests that are abnormal in intensity or focus (e.g, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
• Hyper- or hypo reactivity to sensory input or unusual interests in sensory aspects of the environment (e.g., apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).

C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities or may be masked by learned strategies in later life).

D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.

E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

Note: Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder.

Specify if:

• With or without accompanying intellectual impairment
• With or without accompanying language impairment
• (Coding note: Use additional code to identify the associated medical or genetic condition.)
• Associated with another neurodevelopmental, mental, or behavioral disorder
• (Coding note: Use additional code[s] to identify the associated neurodevelopmental, mental, or behavioral disorder[s].)
• With catatonia 
• Associated with a known medical or genetic condition or environmental factor

Table: Severity levels for autism spectrum disorder

Social (Pragmatic) Communication Disorder

Diagnostic Criteria

A. Persistent difficulties in the social use of verbal and nonverbal communication as manifested by all of the following:

• Deficits in using communication for social purposes, such as greeting and sharing information, in a manner that is appropriate for the social context.
• Impairment of the ability to change communication to match context or the needs of the listener, such as speaking differently in a classroom than on the playground, talking differently to a child than to an adult, and avoiding use of overly formal language.
• Difficulties following rules for conversation and storytelling, such as taking turns in conversation, rephrasing when misunderstood, and knowing how to use verbal and nonverbal signals to regulate interaction.
• Difficulties understanding what is not explicitly stated (e.g., making inferences) and nonliteral or ambiguous meanings of language (e.g., idioms, humor, metaphors, multiple meanings that depend on the context for interpretation).

B. The deficits result in functional limitations in effective communication, social participation, social relationships, academic achievement, or occupational performance, individually or in combination.

C. The onset of the symptoms is in the early developmental period (but deficits may not become fully manifest until social communication demands exceed limited capacities).

D. The symptoms are not attributable to another medical or neurological condition or to low abilities in the domains or word structure and grammar, and are not better explained by autism spectrum disorder, intellectual disability (intellectual developmental disorder), global developmental delay, or another mental disorder.

Dr. Uma Dalvi

Consultant Clinical Psychologist, Bharati Hospital
Pune