How to diagnose Autism Spectrum Disorder?
Due to the clinical complexity and high prevalence rate (1 in 65 children 2-9years of age) of Autism, guidelines have been set for the proper diagnosis of the disease by various national and international pediatric associations. Dr. Puja Kapoor , pediatric neurologist and Dr. Himani Khanna ,Developmental pediatrician gives a simplified approach for the assessment and diagnosis of Autism and the importance of multidisciplinary approach.
Autism diagnosis requires a interdisciplinary coordination between a paediatrician, pediatric neurologist, developmental paediatrician,and a child psychologist.
Currently as biological (eg. Blood, serum, mri ) diagnostic markers are not available ,diagnosis of Autism rests on careful examination of the child ..
Every child between 18 to 24 months should be screened for autism spectrum disorder symptomatology like decrease eye contact, speech delay, improper social interactions and repetitive or unusual behaviours (stereotypies).
A standard screening test The Modified Checklist for Autism in Toddlers (MCHAT) should be applied . It is a freely available downloadable questionnaire (in multiple languages) to be completed by parents. It takes about 10 minutes to complete. It uses a simple scoring procedure based on passed/ failed items. If the child screens positive, a follow up interview is conducted including only those items on which the child failed in initial screening, thus decreasing the likelihood of false-positive results.
If the screening indicates significant symptomatology, a thorough diagnostic evaluation should be performed by a certified psychologist or a developmental paediatrician.
A standard assessment includes interviews with the child and family and a review of past records and historical information. It also includes a review of past and current educational and behavioral interventions and information regarding family history and relevant psychosocial issues. Other comorbid diagnoses is also an important focus of assessment.
Various instruments for the assessment of ASD have been developed like CARS, ADOS ,INCLEN etc.
Psychological tests clarify areas of strength and weakness useful in designing intervention programs to bring maximum results. Communication assessment, including measurements of receptive and expressive vocabulary and language use is helpful for diagnosis and treatment planning. Occupational and physical therapy evaluations may be needed to evaluate sensory and/or motor difficulties. Sleep is an important variable to assess in individuals with ASD. When members of multiple disciplines are involved in assessment, it is optimal that coordination occur among the various professionals
These tests are applied by trained developmental paediatrician and certified psychologist.
A pediatric neurologist should coordinate an appropriate multidisciplinary assessment of children with Autism Spectrum Disorder.
All children with Autism Spectrum Disorder should have a medical assessment, which typically includes physical examination, a hearing screen (if clinical suspicion about hearing deficits is there), a Wood’s lamp examination for signs of tuberous sclerosis, genetic testing, which may include G-banded karyotype, fragile X testing, or chromosomal microarray depending upon clinical scenario.
Unusual features in the child (e.g., history of regression, dysmorphology, staring spells, family history) should have other required investigations. Other causes of secondary autism like infectious (e.g., encephalitis or meningitis), endocrinologic (e.g., hypothyroidism), metabolic (e.g., homocystinuria), traumatic (e.g., head injury), toxic (e.g., fetal alcohol syndrome,lead levels), or genetic (e.g., chromosomal abnormality) should be ruled out.
Certain developmental disorders, most notably Landau-Kleffner syndrome, also should be ruled out by an electroencephalogram (EEG)