Development and Validation of a Culturally Adapted Autism Diagnostic Screening Tool for Nigerian Preschool Populations

This doctoral study develops and validates a culturally adapted autism diagnostic screening tool for preschool-age children in Nigerian populations, addressing a critical measurement gap that has constrained accurate prevalence estimation, early identification, and research in Nigerian autism studies. Internationally developed screening tools such as the Modified Checklist for Autism in Toddlers demonstrate strong psychometric properties in their derivation populations but have documented cultural biases that limit their validity when applied in Nigerian contexts with different social interaction norms, language structures, and help-seeking behaviours. The study follows a rigorous scale development methodology in five phases: systematic review and content mapping, expert panel consultation and item generation, cognitive testing with caregivers and healthcare workers, field piloting across four geopolitical zones, and psychometric validation in a representative sample of one thousand two hundred preschool children. Structural validity, criterion validity, test-retest reliability, and inter-rater reliability are assessed. A community-based diagnostic reference standard using a multi-professional panel provides the gold standard against which screening accuracy is calibrated. The resulting Nigerian Preschool Autism Screening Scale is the first indigenous autism screening instrument developed and validated for Nigerian populations. Its development represents a foundational contribution to Nigerian disability epidemiology and early intervention. Recommendations address deployment through the primary healthcare system and integration into routine child health surveillance. Keywords: autism screening tool, cultural adaptation, validation, Nigerian preschool, diagnostic instrument.