November 12, 2020 Identification and Barriers to Diagnosis of ASD
The American Academy of Paediatrics (AAP) recommends screening of all children at 18 and 24 months for symptoms of ASD with standardized autism screening tests during their primary care visits. This early detection of ASD in toddlers leads to prompt initiation of behavioural interventions which helps improve outcomes to a large extent.
Early manifestations of ASD symptoms are inspected especially the core deficits in social communication.
The general screening tools used to examine developmental milestones at the age 9, 18 and 30 months do not measure social symptoms critical for the diagnosis of ASD, though they make detect the language and cognitive or motor delays in the child.
The symptoms which typically alert the health personnel are –
At 12 months – Does not respond to name
At 14 months – Does not point at objects to show interest
At 18 months – Does not pretend play
- Avoids eye contact and prefers being alone than being in company.
- Has trouble comprehending feelings of others or expressing their own feelings and emotions.
- Shows delayed milestones for speech and language
- Repeats words or phrases constantly (echolalia)
- Gives incoherent answers to questions.
- Has obsessive and compulsive interests.
- Makes repetitive movements like flapping hands or spinning in circles Shows exaggerated responses to the way things sound, smell, taste, look, or feel
Barriers to Diagnosis
Cultural – Language and cultural barriers exist in the healthcare system which need to be addressed to identify high risk ASD children earlier.
Diagnostic – Diagnostic acumen is necessary to identify children with milder symptoms or above average intelligence.
Certain co existing conditions that occur with ASD make the diagnosis difficult. These include insomnia (sleep disorders), gastrointestinal tract symptoms, seizures, attention-deficit/hyperactivity disorder and anxiety.
Many social and communication skills are not developed until the first year of life making the diagnosis further challenging.
Diagnostic tools and tests – The universal screening tests recommended by AAP, have a high sensitivity and specificity. However, when such tests are applied to a condition which has a low prevalence, the predictive value of the tests lowers to around 67% percent.
Future diagnostic interventions – Developing biomarkers that could be used along with the screening methods recommended by the American Academy of Paediatrics could enhance the efficacy of the diagnostic process of ASD.
Thus, biomarkers that can (1) stratify risk for determining the subgroup of child population that should be screened (2) be used as a secondary screening technique and/or (3) confirm the observations of behavioural symptoms of diagnostic tests, could greatly improve the diagnosis and potentially lower the age at which the interventions can be initiated.
- Hyman SL, Levy SE, Myers SM; COUNCIL ON CHILDREN WITH DISABILITIES, SECTION ON DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS. Identification, Evaluation, and Management of Children with Autism Spectrum Disorder. Pediatrics. 2020 Jan;145(1): e20193447. doi: 10.1542/peds.2019-3447. Epub 2019 Dec 16. PMID: 31843864.
- McCarty P, Frye RE. Early Detection and Diagnosis of Autism Spectrum Disorder: Why Is It So Difficult? Semin Pediatr Neurol. 2020 Oct;35:100831. doi: 10.1016/j.spen.2020.100831. Epub 2020 Jun 24. PMID: 32892958.