Development and Validation of Nomogram-Based Prediction Models for Developmental Language Disorder in Bilingual Children

Abstract

Purpose: The challenges of language assessment in bilinguals include a lack of assessment tools and bilingual speech-language pathology services. Additionally, the weighting of subtests in standardized tests has not been empirically explored to maximize sensitivity and specificity. Language exposure might also inform the decision to diagnose bilinguals with developmental language disorder (DLD). This study uses a nomogram, a user-friendly prediction tool, to explore the weighting between bilingual language tasks for diagnostic accuracy and single-language assessment feasibility with language exposure information.

Method: Four hundred nine Spanish-English bilingual children aged 4-7 years completed a standardized bilingual language assessment with six subtests, and caregivers reported language exposure. Additional 326 and 296 Spanish-English bilingual children completed the Spanish or English portions of the assessment, respectively. Nomogram-based prediction models were constructed to evaluate the probability of DLD. Classification accuracy, calibration curves, and decision curve analysis were reported.

Results: The nomogram for the bilingual language assessment was generalizable to another sample, with varying subtest weightings. The addition of bilingual exposure did not improve the classification accuracy of the bilingual assessment, but it was an important variable when assessment was in one language only. Spanish-only assessment with bilingual exposure achieved the minimum acceptable sensitivity and specificity, whereas English-only assessment with bilingual exposure did not.

Conclusions: This study suggests that subtest weighting ratios can help classify Spanish-English bilingual children with DLD. The feasibility of single-language assessment and the clinical use of nomograms are discussed.

Supplemental material: https://doi.org/10.23641/asha.29874254.