Is the Bayley Scales of Infant and Toddler Developmental Screening Test, Valid and Reliable for Persian Speaking Children?

Background: Advances in perinatal and neonatal care have substantially improved the survival of at-risk infants over the past two decades. Objectives: The purpose of this study was to assess the reliability and validity of the Bayley Scales of infant and toddler developmental Screening test in Persian-speaking children. Methods: This was a cross-sectional prospective study of 403 children aged 1 - 42-months. The Bayley scales screening instrument, which consists of five domains (cognitive, receptive, and expressive communication and fine and gross motor items), was used to measure infants’ and toddlers’ development. The psychometric properties examined included the face and content validity of the scale, in addition to cultural and linguistic modifications to the scale and its test-retest and inter-rater reliability. Results: An expert team changed some of the test items relating to cultural and linguistic issues. In almost all the age groups, cultural or linguistic changes were made to items in the communication domains. According to Cronbach’s alpha for internal consistency, the reliability of the cognitive scale was r = 0.79, and the reliability of the receptive scale was r = 0.76. The reliability for expressive communication, fine motor, and gross motor scales was r = 0.81, r = 0.80, and r = 0.81, respectively. The construct validity of the tests was confirmed using a factor analysis and comparison of the mean scores of the age groups. The intra- and inter-rater reliabilities of the Bayley Scales were good-to-excellent. Conclusions: The results indicated that the Bayley Scales had a high level of reliability in the present study. Thus, the scale can be used in a Persian population.