Table 1. Detailed representation of studies.
| Author | Year | Study design | Sample | Objective | Main results | MMAT score (%) |
|---|---|---|---|---|---|---|
| Clark et al. 23 | 2018 | Quantitative non-randomized |
|
Comparison of prognoses according to the initiation of EI for ASD at different ages | Intervention for ASD was most effective in children diagnosed up to 2 years of age. | 80 |
| Maksimovic et al. 24 | 2023 | Quantitative non-randomized | Experimental (n=29) | Comparison of prognoses according to the initiation of EI for ASD at different ages | Autistic symptoms are reduced more in younger children than in older children. EI had better effects in younger children. | 100 |
| Lombardo et al. 25 | 2021 | Quantitative non-randomized | Experimental (n=41) | Comparison of prognoses according to the initiation of EI for ASD at different ages | Shows the importance of early treatment starting ideally before 24 months. Also shows for the first time that blood gene expression characteristics can predict how fast toddlers with ASD respond to early treatment. | 60 |
| Vinen et al. 26 | 2018 | Quantitative non-randomized |
|
Comparison of prognoses according to the initiation of EI for ASD at different ages | The results of school-aged children with ASD who received EI during their preschool years are promising. | 80 |
| Green et al. 27 | 2015 | Quantitative randomized controlled trials |
|
Establishment of prognostic gains from different intervention programs | The specific results suggest that the intervention increased the baby’s attention to parents. Parent-mediated intervention was applied. | 100 |
| Frazier et al. 28 | 2021 | Quantitative non-randomized | Experimental (n=131) | Establishment of prognostic gains from different intervention programs | The EIBI method demonstrated significant changes in the prognosis of ASD, mainly with regard to language. More representative surveys are needed. | 60 |
| MacDonald et al. 29 | 2014 | Quantitative non-randomized |
|
Establishment of prognostic gains from different intervention programs | Significant gains with EIBI, especially when applied before 24 months | 60 |
| Waters et al. 30 | 2020 | Quantitative non-randomized |
|
Establishment of prognostic gains from different intervention programs | The study demonstrates that the EIBI method is effective in community settings for children with ASD starting an intervention in different ages throughout early childhood. | 100 |
| Howard et al. 31 | 2014 | Quantitative non-randomized |
|
Establishment of prognostic gains from different intervention programs | ABA therapy achieved better results than eclectic therapies. | 100 |
| Rahman et al. 32 | 2016 | Quantitative randomized controlled trials |
|
Establishment of prognostic gains from different intervention programs | Use of a tailored (parent-mediated) intervention was effective in low- and middle-income countries. | 100 |
| Perera et al. 33 | 2016 | Quantitative non-randomized |
|
Establishment of prognostic gains from different intervention programs | The home EI results found a statistically significant improvement between pre- and post-intervention in all measured parameters. | 80 |
| Kitzerow et al. 34 | 2020 | Quantitative non-randomized |
|
Establishment of prognostic gains from different intervention programs | The low-intensity early intervention called A-FFIP was effective and brought important prognostic results. | 80 |
| Estes et al. 35 | 2015 | Quantitative non-randomized |
|
Assessment of whether early intervention results are maintained over time | There is evidence that gains from early intensive intervention are maintained for at least 2 years afterwards. | 100 |
| Wei et al. 36 | 2022 |
|
|
Knowledge survey about ASD in people who work or will have early contact with children with ASD | Professionals were able to recognize early signs of ASD but had an inadequate understanding of the disorder. | 80 |
| Coelho et al. 37 | 2021 | Quantitative non-randomized | Experimental (n=55) | Investigation of the development trajectory of two groups of children with ASD in search of predictive factors and adjustments for better intervention strategies | Diagnosis and early intervention are determinants of different prognoses. Parent participation is critical to the success of EI. | 80 |
| Jonsdottir et al. 38 | 2020 | Quantitative non-randomized | Experimental (n=1,586) | Study on screening method and its effects on final prognosis | The M-CHAT-R method was able to detect cases of underdiagnosis at 30 months of age. | 60 |
Abbreviations: MMAT, Mixed Methods Appraisal Tool; ASD, Autism Spectrum Disorder; EI, Early Intervention; EIBI, Early Intensive Behavioral Intervention; ABA, Applied Behavior Analysis.