Cultural adaptation and preliminary psychometric evaluation of the Japanese CSBS-DP-ITC: An initial investigation

Early identification of developmental disabilities is critical. However, Japan lacks a brief parent-report instrument to detect early social-communicative atypicalities in infants aged 6 to 24 months. This initial investigation culturally adapted the Communication and Symbolic Behavior Scales-Developmental Profile Infant-Toddler Checklist (CSBS-DP-ITC) for Japanese (J-CSBS-DP-ITC) infants and evaluated its preliminary psychometric properties.

After authorized translation and a two-round Delphi consultation, the J-CSBS-DP-ITC was administered to caregivers of 79 children aged 6 to 24 months. Internal consistency, construct validity, and preliminary convergent evidence were assessed. Exploratory concordance with a provisional non-diagnostic risk classification was examined to evaluate community feasibility.

The J-CSBS-DP-ITC demonstrated excellent internal consistency (α = 0.798-0.941) and content validity (S-CVI/Ave = 0.98). Exploratory factor analysis supported a three-factor structure. The Speech and Symbolic composites showed preliminary convergent evidence with the Japanese Ages and Stages Questionnaire, Third Edition Communication domain (r = 0.42-0.53, P < 0.01); however, both are parent-report screening tools, and shared method variance may inflate associations. Concordance with the provisional classification showed moderate agreement (κ = 0.525, P < 0.001). Given the small at-risk sample (n = 8) and no diagnostic reference standard, these estimates are tentative.

This study is an initial investigation of the Japanese CSBS-DP-ITC. Preliminary evidence supports its cultural adaptation and internal consistency. Because of the small, non-stratified sample and few at-risk children, sensitivity, specificity, and kappa estimates are tentative. Future studies with at least 100 children per age level and representative sampling are needed before clinical use.