The aim of the current study was to detect age-related changes in the structure of autism symptoms in preschoolers. In 2020-2022 we examined 383 3-4-year-old children with ASD and in 2023-2024 – 528 5-7-year-old children with ASD. The research used 2 online questionnaires, developed and verified earlier for the purposes of the ongoing study, one containing 434 binary items (1-yes, 2-no) for 3-4-year–olds, the other consisting of 330 binary items for 5-7-year-olds. Data collection and filling out these questionnaires was carried out by specialists (psychologists, speech pathologists) of counseling centers, specialized and mass preschool institutions working with children on a regular basis (in counseling mode). The data were collected for children who had already been diagnosed with ASD prior to the current study. The materials, methods and procedures for data collection are detailed in our previous publications. Analysis of data of 3-4-year-old children with ASD, using confirmatory factor analysis (CFI), including multigroup CFI, revealed a stable 7-factor structure in different parts of the sample, including the following factors: 1) "Persistance on Sameness" (PS); 2) "Emotional disregulation" (ED); 3) "Alienation" (Al); 4) "Speech understanding" (SU); 5) "Disinhibition/hyperactivity" (Hyp); 6) "Echolalia" (Ech); 7) "Sensory desintegration" (SD). The factors form 3 independent, unrelated groups of symptoms: 1) Communication disorders (ED, SU, Ech, Al); 2) Sensory disintegration (PS, SD); 3) hyperactivity/disinhibition. A similar analysis of data of 5-7-year-olds revealed an equally stable 8-factor structure similar to that for 3-4-year-olds, but instead of the Alienation factor (Al), 2 new factors appeared: impaired Empathy (Emp) and Motor skills (Mot) (Nasledov et al., 2023, 2024a). Just like in 3-4-year-old children, these 8 factors formed 3 groups of symptoms (secondary factors): 1) Communication disorders (SU, ED, Emp); 2) Sensory disintegration (SD, PS, Ech); 3) Praxis impairment (Hyp, Mot). For 5-7-year-olds, unlike for 3-4-year-olds, the secondarily factors significantly overlap, forming a complex interdependent system. Thus, praxis impairment, including symptoms of hyperactivity/disinhibition and motor delay, begin to increase
emotional disorders and lack of empathy, which are closely related to speech understanding. On the other hand, it was found that praxis impairment begins to be associated with symptoms of sensory disintegration. Apparently, for older preschoolers, the symptoms of speech and motor disorders are key and determine the further educational route.