Autism Screening and Diagnosis

Diagnosing autism spectrum disorders (ASDs) can be difficult, since there is no medical test, like a blood test, to diagnose the disorders.  Doctors look at the child’s behavior and development to make a diagnosis.  

ASDs can sometimes be detected at 18 months or younger.  By age 2, a diagnosis by an experienced professional can be considered very reliable. However, many children do not receive a final diagnosis until much older.  This delay means that children with an ASD might not get the help they need.

Diagnosing an ASD takes two steps:

Developmental Screening

Developmental screening is a short test to tell if children are learning basic skills when they should, or if they might have delays.  During developmental screening the doctor might ask the parent some questions or talk and play with the child during an exam to see how she learns, speaks, behaves, and moves.  A delay in any of these areas could be a sign of a problem.  

All children should be screened for developmental delays and disabilities during regular well-child doctor visits at:

•        9 months

•        18 months

•        24 or 30 months

•        Additional screening might be needed if a child is at high risk for developmental problems due to pre-term birth, low birth weight or other reasons.

In addition, all children should be screened specifically for ASDs during regular well-child doctor visits at:

•        18 months

•        24 months

•        Additional screening might be needed if a child is at high risk for ASDs (e.g., having a sister, brother or other family member with an ASD) or if behaviors sometimes associated with ASDs are present

It is important for doctors to screen all children for developmental delays, but especially to monitor those who are at a higher risk for developmental problems due to preterm birth, low birth weight, or having a brother or sister with an ASD.

If your child’s doctor does not routinely check your child with this type of developmental screening test, ask that it be done.

If the doctor sees any signs of a problem, a comprehensive diagnostic evaluation is needed.

Comprehensive Diagnostic Evaluation

The second step of diagnosis is a comprehensive evaluation.  This thorough review may include looking at the child’s behavior and development and interviewing the parents.  It may also include a hearing and vision screening, genetic testing, neurological testing, and other medical testing.

In some cases, the primary care doctor might choose to refer the child and family to a specialist for further assessment and diagnosis. Specialists who can do this type of evaluation include:

•        Developmental Pediatricians (doctors who have special training in child development and children with special needs)

•        Child Neurologists (doctors who work on the brain, spine, and nerves)

•        Child Psychologists or Psychiatrists (doctors who know about the human mind

Developmental screening can be done by a number of professionals in health care, community, and school settings. However, primary health care providers are in a unique position to promote children’s developmental health.  

Primary care providers have regular contact with children before they reach school age and are able to provide family-centered, comprehensive, coordinated care, including a more complete medical assessment when a screening indicates a child is at risk for a developmental problem.

Screening Recommendations

Research has found that ASDs can sometimes be detected at 18 months or younger. By age 2, a diagnosis by an experienced professional can be considered very reliableHowever, many children do not receive a final diagnosis until they are much older. This delay means that children with an ASD might not get the help they need. The earlier an ASD is diagnosed, the sooner treatment services can begin.

Additional screening might be needed if a child is at high risk for developmental problems because of preterm birth or low birth weight.

In addition, all children should be screened specifically for ASDs during regular well-child doctor visits at:

•        18 months

•        24 months

Additional screening might be needed if a child is at high risk for ASDs (e.g., having a sibling with an ASD) or if symptoms are present.

It is important for doctors to screen all children for developmental delays, but especially to monitor those who are at a higher risk for developmental problems due to preterm birth, low birth weight, or having a sibling or parent with an ASD.  

Early identification of developmental disorders is critical to the well-being of children and their families. It is an integral function of the primary-care medical home and an appropriate responsibility of all pediatric health care professionals.

AAP recommends that developmental surveillance be incorporated at every well-child preventive care visit. Any concerns raised during surveillance should be addressed promptly with standardized developmental screening tests. In addition, screening tests should be administered regularly at the 9-, 18-, and 24- or 30-month visits.

The early identification of developmental problems should lead to further developmental and medical evaluation, diagnosis, and treatment, including early developmental intervention. Children diagnosed with developmental disorders should be identified as children with special health care needs, and chronic-condition management should be initiated. Identification of a developmental disorder and its underlying etiology may also drive a range of treatment planning, from medical treatment of the child to genetic counseling for his or her parents.

The American Academy of Pediatrics (AAP)

What is Applied Behavior Analysis (ABA)?                   

The Virginia Institute of Autism

Applied behavior analysis (ABA) is the process of using behavioral principles to teach new skills and increase desirable behaviors. ABA methods break skills down into small, measurable units and use high rates of positive reinforcement. ABA is committed to objective measurement and data-driven analysis of behavior within relevant settings, like home, school, and the community.  ABA uses many different teaching strategies to increase and maintain desirable behaviors, teach new skills, and generalize behaviors to new environments or situations.

•        Applied behavior analysis (ABA) is devoted to understanding and improving human behavior. It objectively defines and measures behavior, and it focuses on socially significant behavior.

•        Research has shown that individuals with autism do not learn readily from typical environments, but many can learn a great deal given appropriate instruction, namely intensive behavioral intervention.

•        ABA focuses on teaching behavior systematically in a highly structured environment.  Every skill a child with autism does not demonstrate – from relatively simple responses like looking at others, to more complex acts like spontaneous communication and social interaction – is broken down into small steps. Each step is taught using positive reinforcement for appropriate responses. The function of problematic behavior such as tantrums, non-contextual noise, self-injury and withdrawal, is analyzed to determine what in the child’s environment is reinforcing that behavior. By carefully constructing reinforcement in the child’s environment and by teaching him or her replacement skills, many problem behaviors can be reduced or eliminated.

•        Children are given many opportunities to practice new and emerging skills until desired responses are performed readily, easily and independently. Data are collected, graphed and analyzed to quantify a child’s progress.

•        As a child progresses, skills are also practiced and reinforced in less structured situations, and instruction may be delivered not only in one-on-one settings, but also in group instruction.  Emphasis is given to teaching children to generalize learning and skill demonstration from one environment to another, from school to home, from one instructor to another, and ultimately to community settings.

What Behavior Analysis is Not:

•        A teaching method (e.g. miss-miss-prompt, discrete trial, verbal behavior, etc). These methods use the principles of behavior analysis, but do not define ABA.

•        A quick fix. ABA is not a miracle cure. It is labor intensive and takes a lot of time.

•        Specific to autism. The principles of behavior apply to everyday life, and ABA can be effective in many settings, including typical classrooms, work environments, and at home.

Is ABA the same thing as discrete trial instruction or the Lovaas Method?

No.  Discrete trial instruction is a specific instructional method that can be used in the context of an ABA program.  It involves multiple trials of presenting a direction (called the discriminative stimulus or SD), eliciting an independent or prompted response, and delivering a consequence (reinforcement).  The Lovaas Method or Model is a program based heavily on discrete trial instruction, with specific guidelines in terms of intensity and focus of intervention.  More information about the Lovaas Method can be found at  

Other teaching strategies that fall under the umbrella of ABA include incidental teaching, Verbal Behavior, Pivotal Response Training, task analysis instruction, and fluency-based instruction.  For more information on specific ABA-based teaching methodologies, visit the Association for Science in Autism Treatment.

Is ABA just for students with autism?

No. ABA is a much broader science that is used in many fields, including marriage counseling, sports psychology, corporate management, animal training, and many more.  Parents and teachers can certainly apply these principles to working with their children and students without autism as well.

What is behavior?

Behavior is anything a person or animal does.  The term behavior is sometimes used to refer to disruptive behavior (e.g. “He had a lot of behaviors today.”), but actually refers to anything a person does, whether positive, negative, or neutral.  In a school setting, reading, working out a math problem, kicking a ball, greeting someone, and washing your hands are all behaviors that can be taught and reinforced.  

What is reinforcement and why is it important?

Reinforcement is a process in which an event follows a behavior and increases the likelihood of that behavior occurring in the future.  In positive reinforcement, something is added to the environment and increases the likelihood of the behavior occurring in the future (e.g. If a child asks for a cookie and gets a cookie, he is more likely to ask in the future. If I go to work and get a paycheck, I am more likely to go to work in the future).  In negative reinforcement, something is removed or avoided, thereby increasing the likelihood of the behavior occurring in the future (e.g. If a student asks appropriately for a break and gets a break, he is more likely to ask in the future, If taking Ibuprofen gets rid of my headache, I am more likely to take that type of pain reliever in the future).  Punishment is often confused with negative reinforcement, but they are not the same thing; punishment is a procedure that decreases the likelihood of a behavior occurring in the future.

The behavioral approach is based on an assumption that, if a behavior is occurring, it is being reinforced in some way.  For students with autism, the social and intrinsic reinforcers that affect many of us may not be as powerful.  Therefore, we often must begin by offering more explicit reinforcers (preferred activities, toys, or foods) to build appropriate skills, and pair these with other more normalized reinforcers over time.  In a classroom setting, reinforcers may include access to privileges, verbal praise, stickers, or breaks from work.  It is important, however, to recognize that an item is not a reinforcer if it is not successful in increasing the desired behavior.

Autism spectrum disorders (ASDs)

ASDs are a group of developmental disabilities that can cause significant social, communication and behavioral challenges.  People with ASDs handle information in their brain differently than other people.

ASDs are “spectrum disorders.”  That means ASDs affect each person in different ways, and can range from very mild to severe.  People with ASDs share some similar symptoms, such as problems with social interaction.  But there are differences in when the symptoms start, how severe they are, and the exact nature of the symptoms.

Autism can be reliably diagnosed by or before age 3. Parents and expert clinicians can usually detect symptoms of autism during infancy, although a formal diagnosis is generally not made until the child fails to develop functional language by age 2. Boys are three-to-four times more likely to be affected by autism than girls. Autism occurs in all racial, ethnic, and social groups.

Types of ASDs

There are three different types of ASDs:

•        Autistic Disorder (also called “classic” autism)

This is what most people think of when hearing the word “autism.”  People with autistic disorder usually have significant language delays, social and communication challenges, and unusual behaviors and interests. Many people with autistic disorder also have intellectual disability.

•        Asperger Syndrome.  People with Asperger syndrome usually have some milder symptoms of autistic disorder.  They might have social challenges and unusual behaviors and interests.  However, they typically do not have problems with language or intellectual disability.

•        Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS; also called “atypical autism”)

People who meet some of the criteria for autistic disorder or Asperger syndrome, but not all, may be diagnosed with PDD-NOS. People with PDD-NOS usually have fewer and milder symptoms than those with autistic disorder.  The symptoms might cause only social and communication challenges.

Autism has its origins in the first weeks or months of life. It is characterized by marked problems in social interaction (autism), as well as by delayed and deviant communication development (speech is absent in about 50 percent of cases) and various other behaviors which are usually subsumed in the term 'insistence on sameness.' Such behaviors include stereotyped motor behaviors (hand flapping, body rocking), insistence on sameness and resistance to change. Both categorical and dimensional approaches to diagnosis have been used, as for instance in the DSM-IV Worldwide Field Trial. Many individuals with autism exhibit mental challenges on the basis of their full-scale (or averaged) IQ score; however, unlike most people with primary mental challenges, those with autism often have marked scatter in their development, so that some aspects of the IQ, particularly nonverbal skills, may be within the normal range. Autism is sometimes observed along with other medical and psychiatric conditions such as Fragile X syndrome.

Yale School of Medicine

Children and adults with autism find it difficult or impossible to relate to other people in a meaningful way and may show restrictive and/or repetitive patterns of behavior or body movements. While great strides are being made, there is no known cause, or a known singular effective treatment for autism.

There are five developmental disorders that fall under the Autism Spectrum Disorder umbrella and are defined by challenges in three areas: social skills, communication, and behaviors and/or interests. Autism is the fastest-growing developmental disability.

Autistic Disorder - occurs in males four times more than females and involves moderate to severe impairments in communication, socialization and behavior than other disorders on the spectrum. People with Asperger's syndrome usually function in the average to above average intelligence range and have no delays in language skills, but often struggle with social skills and restrictive and repetitive behavior.

Rett Syndrome - diagnosed primarily in females who exhibit typical development until approximately five to 30 months when children with Rett syndrome begin to regress, especially in terms of motor skills and loss of abilities in other areas. A key indicator of Rett syndrome is the appearance of repetitive, meaningless movements or gestures.

Childhood Disintegrative Disorder - involves a significant regression in skills that have previously been acquired, and deficits in communication, socialization and/or restrictive and repetitive behavior.

Living with Autism

People with autism have challenges in the areas of communication, socialization and restricted/repetitive behaviors. A few examples:


•        Development of language is significantly delayed

•        Some do not develop spoken language

•        Experience difficulty with both expressive and receptive language

•        Difficulty initiating or sustaining conversations

•        Robotic, formal speech

•        Repetitive use of language

•        Difficulty with the pragmatic use of language


•        Difficulty developing peer relationships

•        Difficulty with give and take of social interactions

•        Lack of spontaneous sharing of enjoyment

•        Impairments in use and understanding of body

language to regulate social interaction

•        May not be motivated by social reciprocity

or shared give-and-take

Restricted/Repetitive Behavior

•        Preoccupations atypical in intensity or focus

•        Inflexibility related to routines and rituals

•        Stereotyped movements

•        Preoccupations with parts of objects

•        Impairments in symbolic play

Autism FAQ

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