Sergey A. Miroshnikov

Background. Symptoms of autism spectrum disorder (ASD) and developmental delay (DD) often overlap in preschool children, yet their manifestation may change with age. While previous studies have described symptom profiles in separate age groups, little is known about how these symptoms unfold longitudinally across the preschool period. In particular, comparative trajectories of symptom manifestation between children with ASD and those with DD across three distinct age ranges remain underexplored. Understanding such trajectories is critical for early differential diagnosis and intervention planning. 

Objective. To understand age-related changes in symptom presentation, which is essential for differentiating between ASD and DD, as well as for selecting optimal intervention strategies.

Design. A three-factor model of autism symptoms was established for 1–2-year-old children to capture age-specific patterns of symptom manifestation, which were compared with those observed in 3–5- and 6–7-year-olds with ASD. The overall structure of the model and its measurement equivalence were confirmed across the full preschool age range. Factor scores were calculated as the mean of consistent items for each participant. Children with ASD and DD were then compared on these factor scores to examine age- and diagnosis-related trajectories in symptom expression.

Results. The three symptom domains—Communication Disorders, Sensory Disintegration, and Hyperactivity—persisted throughout the preschool years in children with ASD, with Communication Disorders showing the highest prevalence in the youngest age group (1–2-year-olds). Hyperactivity and Sensory Disintegration were commonly observed in both children with ASD and those with DD at age 1–2 years. However, while all three symptom domain decreased across preschool age in children with DD, they remained pronounced in children with ASD.

Conclusion. The observed patterns of symptom manifestation reflect fundamental and stable neurodevelopmental differences, shaped by a range of interacting factors. These patterns also capture developmental shifts, in which the prominence of specific symptom domains changes with age and experience. Among the symptom domains examined, Communication Disorders emerged as the most distinguishing feature for differentiating children with ASD from those with DD in early childhood.

Background. It is known that the earlier a child is diagnosed with developmental delay (DD), the more promising his/her cognitive development can be. Various screenings are used worldwide for early detection of developmental problems. However, timely diagnosis of DD is not sufficiently carried out in Russia at present.

Objective. Elaboration of screening scales to quickly monitor the mental development of five- to six-year-old Russian children was the objective of this study. The scales we developed involved the use of modern information technologies to obtain reliable results.

Design. This study was carried out with a sample of 1,860 children. The formal procedure for multilateral monitoring of child development was used for data collection, involving a much more extensive set of tasks than in traditional tests of abilities; this allowed for a wider variation of the factor structure. For the five-year-olds, 349 tasks were used, and 292 for the six-year-olds. To construct scales for each age group (six–seven items in each), which would most accurately predict the diagnosis (Norm or DD), factor and discriminant analysis were carried out. To verify the prediction model, structural equation modeling (SEM) was used.

Results. As a result of the study, we developed scales which had similar types of variables for each age group (simpler for the five-year-olds and more complex for the six-year-olds). The common variables were logical reasoning, motor skills, and general awareness; two other scales were added for the six-year-olds: sustained attention and counting. According to the SEM, these scales are indicators of the general ability factor, and the latter one (general awareness) is the main predictor of the diagnosis.
Conclusions. Short scales for rapid identification of DD in Russian preschoolers were constructed, which allow the use of computer technology to uncover the risk group among five- and six-year-olds in a timely fashion, and have high sensitivity and specificity of the forecast (not lower than 94%).

 Background. While various screening systems are used worldwide for early detection of developmental delay (DD), Russia still does not have such a screening system in place, even though a good prognosis for the cognitive development of a child with DD depend strongly on the time of the diagnosis. 

Objective. The objective of this study was to create a system to rapidly monitor the mental development of four- to five-year-old Russian children, a system that allows for the use of modern information technologies to obtain reliable results. 

Design. This study was carried out with a sample of 1,232 children. For data collection, the multifactor study of mental development tool was used as a part of a so ware complex for longitudinal research. This tool included a much more extensive set of tasks than in traditional tests of abilities, allowing for a wider variation of the factor structure. For the 4-year-olds, 236 tasks were used and 349 for the 5-year-olds. Factor and discriminant analysis were carried out to construct scales for each age group (6–7 points in each), which most accurately predict the diagnosis (Norm/DD). Structural equation modeling (SEM) was used to verify the prediction model. 

Results. Two scales were elaborated, which coincided with the type of variables combined in each of them regardless of age (for 4-years — simpler and for 5-years — more complex): logical reasoning, motor skills, and general awareness (listed in descending order of contribution to the prediction). SEM confirmed that the selected scales are indicators of the general ability factor, which is the main predictor of the diagnosis. 

Conclusions. Two short scales for the rapid diagnosis of DD in preschool children were constructed, allowing the use of computer technology to timely identify the risk group among 4- and 5-year-olds with high sensitivity and specificity of the forecast (not lower than 95%).