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How is Autistic Spectrum Disorder Diagnosed?

It is important that individuals with Autistic Spectrum Disorder are diagnosed at an early stage, so that appropriate interventions can begin as soon as possible. There is no definitive test used to diagnose Autistic Spectrum Disorder, diagnosis is based on developmental history taking, observations and direct assessment in a range of settings.

Parents/carers may notice the symptoms of an Autistic Spectrum Disorder when the child is around two years old, however mild symptoms may not be detected until adulthood.

For the diagnosis of Autistic Spectrum Disorder, problems in at least one of communication, social skills and/or restricted behaviour will need to be present. Normally the diagnosis will take part in two stages. The first stage will involve developmental screening tests to assess what developmental milestones have been reached and also to identify changes in behaviour. Screening will not provide a diagnosis; it will however help to determine whether additional evaluations by specialist health professionals are required. Several screening instruments have been developed to aid the initial assessment stages, some of which include:

  • The Checklist of Autism in Toddlers - involves questionnaire with the parents/carers and an observation of the child's behaviour
  • The Social Communication Questionnaire - questionnaire in two parts. The first part assesses the child's behaviour in the past 3 months, the second asks questions about the child's lifetime developmental history
  • The Autism Spectrum Screening Questionnaire - questionnaire assessing social interaction, communication, repetitive behaviour and motor clumsiness

If following these initial screening tools the child shows indications of possible Autistic Spectrum Disorder, further more in-depth assessments will be required.

Comprehensive diagnostic evaluations are required if the screening tools have highlighted a potential for the child having an Autistic Spectrum Disorder. A specialist assessment will normally be carried out by different professionals in the multi-disciplinary team including a psychologist, neurologist, psychiatrist, speech and language therapist, or other health professionals who diagnose children with Autistic spectrum Disorders.

The assessment should involve the following key areas:

  • History taking with the parents/carers to assess what age-appropriate, developmental milestones the child has achieved
  • Direct observation of the child - evaluating how they behave, play and interact with others. They will also observe language and cognitive ability
  • Discussing with the parents/carers how the child behaves in other settings and situations
  • Collecting information regarding how the child gets on in their day to day life e.g. in school/nursery/home/during play time
  • Blood tests - to test whether the child has any genetic conditions that are known to be linked with Autistic Spectrum Disorders
  • Measures developed specifically to diagnose Autism are often used

A diagnosis of Autism Spectrum Disorder will be made following a variety of detailed and in-depth assessments carried out by a range of professionals. A diagnosis will be made following a strict diagnostic criteria set out in the ICD-10 (International Classification of Diseases).

To arrange an assessment with one of our therapists please email or call 03300 886 693.

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