The present study aimed to evaluate the developmental outcomes of children aged 1 to 42 months in Yazd, Iran, using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). The findings shed light on the prevalence and patterns of developmental disorders across various domains, highlighted the influence of parental education on developmental disorder prevalence, and compared the BSID-III scores with the Ages and Stages Questionnaire (ASQ) outcomes. In the context of the broader literature, these results contribute to the understanding of developmental assessment in early childhood and underscore the importance of considering cultural and contextual factors in interpreting assessment outcomes. This section will discuss the study's findings in the context of existing literature, highlight implications for clinical practice and policy, address methodological considerations, and suggest areas for future research.
The observed prevalence rates of developmental disorders in the cognitive, language, and motor domains among the study population add to the growing body of evidence that emphasizes the significance of early developmental assessment. The findings of this study align with previous research conducted in other settings. For instance, studies such as Valla et al. [1] and Anderson and Burnett [2] have reported varying rates of developmental delays, emphasizing the importance of a comprehensive approach to assessment. Valla et al. conducted a regional population-based longitudinal study and found a 19.7% prevalence of suspected developmental delays in infants aged 6 to 12 months [1]. Our study's cognitive, language, and motor scales showed similar patterns, with prevalence rates ranging from 13.6–20.1%. The diversity in developmental disorder prevalence across different domains may be attributed to the multifaceted nature of development and the intricate interplay of genetic, environmental, and cultural factors. Furthermore, the findings resonate with research by Gould et al. [3], highlighting the long-term implications of early developmental assessment.
Parental education emerged as a significant factor influencing the prevalence of developmental disorders, particularly among fathers. Our study revealed an inverse correlation between parental education levels and the occurrence of developmental disorders. These findings align with previous research by Klein-Radukic and Zmyj [4], highlighting the role of socioeconomic factors in developmental outcomes. Moreover, our results are consistent with the study by Pitchik et al. [18], who reported a positive correlation between maternal education and the ASQ and BSID-III scores, indicating better developmental outcomes. Similar observations were made by Ballot et al., who found that higher parental education levels were associated with better developmental outcomes [8]. The inverse correlation between parental education levels and developmental disorder prevalence underscores the potential benefits of targeted interventions and parental education programs. Similar findings have been documented in other cultural contexts, such as the study by Hoskens et al. [5], demonstrating the importance of addressing parental education as a key factor in early childhood development.
Comparisons between the BSID-III scores and the ASQ outcomes revealed variations in developmental status classification. The observed discordances between the two assessment tools resonate with the broader literature. Madaschi et al. [6] and Adams-Chapman et al. [7] similarly noted differences in developmental assessments, highlighting the complexity of capturing the full spectrum of developmental progress through a single assessment tool. In consistent with our results, another study by Gollenberg et al. explored the concurrent validity of parent-completed ASQ and the BSID-II [9]. Such disparities underscore the need for comprehensive evaluation and the use of multiple assessment tools to obtain a holistic view of children's developmental trajectories. The mixed concordance rates observed in this study mirror findings by Ballot et al. [8], emphasizing the importance of cautious interpretation of assessment results.
The findings from the present study echo those of previous research indicating the need for culturally sensitive adaptations of developmental assessment tools. Soleimani et al. (2022) standardized the BSID-III for Persian children, underscoring the importance of adapting these tools to the local context [16]. Similar sentiments are shared by Madaschi et al. (2016), who emphasized the necessity of transcultural adaptation and psychometric evaluation of assessment tools for accurate results [6]. The diverse population samples used in these studies, including those from Ethiopia, Kenya, Nepal, and Cambodia, highlight the cross-cultural applicability of developmental assessment tools [10, 11, 13, 14].
Several methodological limitations should be acknowledged in interpreting our study's findings. The cross-sectional design, while allowing us to explore associations, does not permit the establishment of causal relationships. To gain a deeper understanding of long-term developmental trajectories and causal links, future research should employ longitudinal designs with larger, more diverse samples. Additionally, our study's focus on children referred with suspected developmental delay may introduce selection bias, potentially affecting prevalence rate estimates. Longitudinal studies would provide a more robust foundation for causal inferences and a broader representation of children, including those without suspected delays.
To conclude, the findings of this study provide valuable insights into the developmental outcomes of children aged 1 to 42 months in Yazd, Iran. The observed prevalence rates of developmental disorders, the influence of parental education, and the comparison of assessment tools underscore the importance of early developmental assessment and tailored interventions. These findings contribute to the broader literature on developmental assessment and highlight the need for culturally sensitive approaches to understanding and addressing developmental delays in diverse populations.