Objectives: To develop a culture and linguistically appropriate neuro-developmental disorders screening tool (NDST) for ten NDDs in children aged 2-9 years; and to validate and test field application at five sites across India.
Methods: Development of NDST: The 39 questions NDST was developed in English based on the ten questions questionnaire(TQ) to screen for a larger number of NDDs. It was translated to vernacular language and piloted on 593 subjects (325 children with confirmed diagnosis of NDD and 268 with no NDD, aged 2-9 years) identified from outpatient/specialty clinics of nine participating medical institutions located in different parts of India. Piloting revealed that the content validity of individual item and item-clusters, contextual meaning and relevance of examples were not always clear in every region. Several questions lost their essence and content due to lack of suitable equivalents in Indian languages after translation from English phrases. The questions needed re-sequencing as clustering of disability specific items invited biased response. Consequently, the instrument was re-discussed, modified and reframed in Hindi and re-sequenced. This version of NDST was translated to English. Both English and Hindi versions were shared with site investigators for translation into respective vernacular languages. The modified NDST retained cultural flavor, was easy for paramedical staff across the country to administer, and for parents to understand. The NDST was subjected to reliability tests (test re-test and inter-rater) at two sites (New Delhi and Thiruvananthapuram). The test-retest reliability was measured by Spearman-Brown split-half reliability coefficient and the inter-rater reliability through intra-class correlation coefficient. Test re-test reliability coefficient was above 0.8 for 35 (89.7%) questions for both doctors and research assistants. Inter-rater reliability correlation co-efficient was above 0.8 for 21 (53.8%) questions; no item had a reliability coefficient less than 0.5. No item during test-retest reliability assessment and three items in the inter-rater reliability test were in the 0.5-0.6 range at both sites. Overall, the NDST was performing similarly in New Delhi and Thiruvananthapuram and between doctors and research assistants.Validation: Subsequently, NDST has been applied in the field on 4000 children (2-9 years age) selected from five regions using population proportionate to size cluster sampling technique (200 clusters of 20 children – five boys and five girls in each of 24-71 and 72-107 months age group), separately by a field assistant and a doctor, on the same child and validated against the consensus clinical criteria diagnoses.
Results: Preliminary analyses from the sites suggest a sensitivity and specificity of NDST above 90% when the field assistant administered the instrument. The specificity increased further by 3.5% when NDST was applied by the doctor on the screen positives. Analysis is ongoing and the detailed results shall be presented.
Conclusions: This experience of constructing a culture appropriate tool may be extended to other LMICs.
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See more of: Symptoms, Diagnosis & Phenotype