Autism Diagnosis | Diagnosing ASD | Developmental Monitoring & Autism Screening | FAQ on ASD Assessment

Diagnosing ASD

Getting an autism diagnosis:

There are several autism screening tools that can be used, including the Autism Diagnostic Observation Schedule (ADOS) performed by a child psychologist, and parent interview scales such as the Child Autism Rating Scale (CARS), Autism Diagnostic Interview-Revised (ADI-R), and Developmental, Dimensional and Diagnostic Interview (3DI). Measures of child’s speech and language skills and intellectual ability also help professionals plan intervention.

Monitoring, screening, evaluating, and diagnosing children with ASD as early as possible is important to make sure children receive the services and support they need to reach their full potential. There are several steps in this process. 


Autism Screening

Step 1: Developmental Monitoring

Developmental monitoring observes how your child grows and changes over time and whether your child meets the typical developmental milestones in playing, learning, speaking, behaving, and moving. Parents, grandparents, early childhood providers, and other caregivers can participate in developmental monitoring. You can use a brief checklist of milestones to see how your child is developing. If you notice that your child is not meeting milestones, talk with your doctor or nurse about your concerns.

Autism Screening - Developmental Monitoring

Step 2: Autism Screening - Developmental Screening

Developmental Screening takes a closer look at how your child is developing. Your child will get a brief test, or you will complete a questionnaire about your child. The tools used for developmental and behavioral screening are formal questionnaires or checklists based on research that ask questions about a child’s development, including language, movement, thinking, behavior, and emotions. Developmental screening can be done by a doctor or nurse, but also by other professionals in healthcare, community, or school settings. Developmental screening is more formal than developmental monitoring and normally done less often than developmental monitoring. Your child should be screened if you or your doctor have a concern. However, developmental screening is a regular part of some of the well-child visits for all children even if there is not a known concern.


Autism Screening - Developmental Screening

FAQ on Autism Assessment

1. At what age can autism be diagnosed?

Although some children show autistic features in early infancy, it can be difficult to give a definitive diagnosis of autism before 2 to 2.5 years old.
In addition, some behaviours associated with autism are also frequently found in children who have developmental delay. This may make it difficult to distinguish between the two conditions in very young children. However, many children with autism can be screened for the disorder from as young as 18 months. Your doctor will determine the most suitable age for diagnosis based on the developmental status of the child.

2. How is the diagnosis of autism made? Are there any special tests the doctor can do to determine whether my child is autistic?

At present, there are no diagnostic tests for ASD, unlike certain medical conditions where a blood test or X-ray may provide exact results.
Instead, the diagnosis is based on a detailed developmental history and observation of the child’s behaviours. However, autism can co-exist with certain medical conditions and your doctor may recommend blood tests, genetic tests or brain scans to rule out the presence of these other conditions.

3. What are the tests that the pediatricians and specialists will use in the diagnosis of ASD?

A detailed medical and developmental history from the parents is obtained by the paediatrician.
Behavioural observations and developmental screens are also performed in the clinic. The doctor may also give out questionnaires to parents and teachers to ascertain if the child has difficulties at home or in school that may be related to autism. A physical examination will also be performed to exclude other co-existing medical conditions.
Next, psychological testing will involve tools developed specifically for diagnosing ASD. These include the Autism Diagnosis Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS), Child Autism Rating Scale (CARS) and Developmental, Dimensional and Diagnostic Interview (3DI).
The ADI-R is a standardised, semi-structured clinical interview for caregivers. The interview can take up to 3 hours and it focuses on behaviours in three areas: quality of social interaction, communication and language, and repetitive, restricted and stereotyped interests and behaviour.
The ADOS is a semi-structured assessment of communication, social interaction and play or imaginative use of materials for children suspected of having ASD. The ADOS requires a 30 to 45 minutes observation period of the child’s behaviour and interaction.
CARS aids in evaluating the child’s body movements, adaptation to change, listening response, verbal communication and relationship to people. It is suitable for use with children over 2 years of age. The examiner observes the child and also obtains relevant information from the parents.
3DI is a semi-structured parent interview designed to facilitate the evaluation of suspected ASD.
In addition, testing of the child’s cognitive skills may be necessary and can be assessed with the Vineland Adaptive Behaviour Scales 2nd Edition (VABS-II) for younger children and standardised IQ testing for older children.

4. How is a typical autism assessment like?

A typical autism assessment will take at least 2 hours.
These assessments will include a combination of detailed parental interviews and child observations using the tools mentioned above. These are usually scheduled to be completed within a day. However, depending on the child’s cooperation, interviews and observations may be scheduled on different visits. Generally, for children less than 5 years old, two assessment sessions will be booked. For children more than 5 years old, three assessment sessions will be booked.

5. What can I do to prepare for the autism assessment session?

You can do the following:
  • Try to schedule the autism assessment to take place when your child is at his best. If your child needs to take an afternoon nap, then don’t schedule the session in the afternoon.
  • Allow the child to have plenty of rest the night before as well as a good breakfast on the day of the test.
  • Note your child’s developmental milestones (e.g. age of walking, first single words, etc.) and any unusual behaviours (e.g. spinning body, lining up objects, etc.) and how long these behaviours have lasted. All these information will be useful during the parental interview.

6. Why is it important to make the diagnosis? Can I wait till my child is much older?

It is important to identify children with possible ASD early so that they can receive appropriate intervention and support services. Research indicates that early intervention can improve children’s developmental outcomes, including improved language, cognitive, social and motor skills.
The earlier a diagnosis is made, the sooner the child can participate in early intervention programmes that are specifically designed for ASD.
There are situations where a diagnosis may also be helpful for schoolgoing children. For example, a diagnosis allows support of the Special Needs Officer (SNO) in mainstream schools or when seeking examination accommodation.