Diagnostic Assessment for Autism Spectrum Disorder in Children and Young People in NZ: What to Expect.

January 28, 2016

The diagnosis of Autism Spectrum Disorder (ASD) in children and young people is important for several reasons. Diagnosis allows access to appropriate resources, support and assistance. More importantly, it facilitates understanding of the child by those who live with them, teach them and interact with them in their everyday lives. It also enables families to plan for a future that may be somewhat different to the one they expected for their child and for themselves.

The NZ Autism Guideline provides detailed guidelines on what constitutes a best practice assessment. In reality, the assessment process throughout NZ varies considerably depending on factors including the age of the child, the configuration of local services, whether there is a service in your area with clinicians who are specialist in ASD, and if so, whether the ASD expertise sits across a multidisciplinary team or whether it sits with a sole clinician who has ASD specialist knowledge.

Wherever your child’s assessment takes place and whether it is by one person or a team, a diagnostic assessment should include:

  • Informed consent.

This would typically be a discussion with you about the purpose of the assessment, what is involved for you and your child and the opportunity for you and your child (if they are old enough and have sufficient language ability) to ask any questions about the risks and benefits of diagnosis and who the results will be shared with. The opportunity to clarify what is happening, to ask questions or to change your mind about having the assessment should be available to you throughout.

  • A comprehensive developmental and family history.

You can help with this process by bring your child’s health development record, which hopefully contains information about your child’s birth history and developmental milestones. When and how language and communication developed is of particular importance in the diagnosis of ASD. It is also helpful if you can find out from your extended family about whether there are family members who have had differences or difficulties in their social skills, communication skills, learning or mental health. This is of interest because ASD does tend to run in families.

  • Observations of the child in different environments e.g. in clinic, at preschool or school and at home.

Observations of the child should be systematic and focused on social, communication and play skills. In very young children with severe ASD symptoms, the diagnosis of ASD can be made by an experienced clinician on the basis of a brief clinic-based observation in combination with a focused discussion with caregivers. More subtle ASD presentations may require observations over time in different settings, including in unstructured settings with unfamiliar people. Sometimes diagnosis may involve the use of an assessment tool such as the Autism Diagnostic Observation Schedule. There are times where direct observation can be difficult: for example older children or adolescents may not welcome an observer in the classroom or playground. In these cases the clinician may ask to interview the young person’s teacher about their social and communication skills in the classroom or playground.

  • A communication assessment.

Ideally this is done by a speech-language therapist (SLT) with ASD specific skills and experience. Within specialist ASD services, the SLT will be part of that services’ multidisciplinary team. In other cases the speech therapist may work for another agency, for example the Ministry of Education, but their assessments will  form part of the information that the diagnosing clinician will consider.

  • Assessment of mental health and behaviour.

ASD often goes hand in hand with other conditions. Conditions such as Attention-Deficit/Hyperactivity Disorder, learning difficulties, anxiety and behaviour problems are common, and the diagnosing clinician will be thinking about whether the child has one or other of these conditions (differential diagnosis) or a mix of some or all of them (comorbid conditions).

  • An assessment of the needs of your family.

Having a child with a developmental condition is stressful and there is evidence that the parents of children with ASD experience higher levels of stress than parents of children with other conditions. Most District Health Boards now employ an ASD services coordinator whose role it is to ensure that families receive information about services and supports and make referrals where necessary.


The following are parts of an ASD assessment which while not essential to the diagnosis, are desirable and can be helpful for some children and young people.

  • A medical assessment.

Although not part of the diagnosis, a medical assessment is usually carried out. There are some medical conditions, such as epilepsy, that are more likely in the ASD population. Testing for chromosomal abnormalities may be recommended after discussion with you. Young children should always have their hearing checked.

  • A cognitive assessment.

In services that employ psychologists, a cognitive assessment may be carried out. This can be helpful in identifying areas of strength and difficulty in the young person’s thinking skills. It can also be helpful in establishing what kinds of disability supports the child or young person might be entitled to (there are different services available for children who have an intellectual disability as well as ASD). Finally it can be helpful in predicting the level of support that might be required in the future.

  • An assessment of sensory and motor development.

Sensory differences are common in ASD, so you will always be asked about whether your chid has now or in the past overreacted or under-reacted to sound, touch taste. Problems with coordination or clumsiness are also common, which can affect how the child manages tasks including dressing, feeding, handwriting. These areas can be assessed in detail by an Occupational Therapist (OT) if they are affecting the child’s ability to manage those day to day activities.


The length of time a diagnostic assessment takes varies depending on the age of the child, their symptom severity, the type of assessment that is necessary and how many clinicians are involved in the assessment. Usually at the first meeting the clinician(s) will be able to tell you what they are intending to do and why, and how long they expect it to take.  A diagnostic assessment could take as little as one hour for a young child with severe symptoms. However a child with more subtle symptoms or a complex presentation which requires comprehensive assessment could take up to eight hours. This might involve two or more extended clinic visits as well as one or more observations in the child’s home, preschool or school and would take place over days or weeks.

The diagnostic process can be difficult for families. Whether a diagnosis of ASD is made or not, it is never easy to go through a process which can feel like your child, you, your family, your parenting, your own coping are being enquired about in a level of detail which can feel intrusive. The diagnosis itself, whether you have been expecting it or even hoping for it can be a real shock. A common reaction to diagnosis is difficulty remembering any of the discussion after the diagnosis was made. You should always feel able to contact the person/people who did the diagnostic assessment to arrange a follow-up appointment to ask any questions you might have in the days following the diagnosis. Doubt about the accuracy of the diagnosis or about the competence of the clinician(s), anger, grief and despair are also common. Other people experience a great sense of relief as there is now an explanation for their experience, although this relief can then give way to anxiety about what the future may hold. When the diagnosis is made with older children and adolescents there needs to be discussion about what the young person needs to be told, when and by whom.

There are many ways in which support can be obtained through this time; through services such as Altogether Autism and Autism NZ and through the ASD coordinators. You are not alone and you will adjust to this new reality although it may take some time.


Written by: Jenny Gibbs, Consultant Psychologist



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