Diagnostic Accuracy of Indian Scale for Assessment of Autism in Indian Children Aged 2-5 Years

ABSTRACT

Objective: To determine the diagnostic accuracy of Indian Scalefor Assessment of Autism (ISAA) in children aged between 2-5years.Design: Study of diagnostic accuracySetting: Tertiary level hospital, (November 2015 – November2017).Participants: A consecutive sample of 500 children withsuspected Autism (delay or regression of developmentalmilestones, delay or regression in speech, age-inappropriateunderstanding, behaviour, play and/or social interaction) wasrecruited.Procedure Each child underwent an expert comprehensiveassessment of Autism (reference tool) that included history,observation, examination, diagnostic criteria for Autism SpectrumDisorder (ASD) of the Diagnostic and Statistical Manual of MentalDisorders’, 5th edition, Childhood Autism Rating Scale-2(CARS2), developmental status and adaptive function. This wasfollowed by the administration of ISAA (test tool) in Hindilanguage. Parameters of diagnostic accuracy and ReceiverOperating Characteristic curves were computed.Main Outcome Measures: ASD based on (i) expert assessment,(ii) CARS-2, and (iii) ISAA.Results: In children aged 2-3 years, sensitivity of ISAA was 100%(95% CI 98.2% -100%), specificity 28.9% (95% CI 17.7% to43.4%), positive likelihood ratio 1.4 and negative likelihood ratio 0.In 3-5 year olds, sensitivity was 99.6% (95% CI 97.6% to 99.6%),specificity 33.3% (95% CI 15.1% to 58.3%), positive likelihoodration 1.5 and negative likelihood ratio 0.01. The degrees ofautism based on the existing cut off values were inaccurate.Conclusions: ISAA has sub-optimal performance in diagnosingand assessing severity in 2-5 year old children.