Efficacy of very early interventions on neurodevelopmental outcomes for infants and toddlers at increased likelihood of or diagnosed with autism: A systematic review and meta-analysis.

This study looked at whether autism interventions starting very early (before age 2) help children's development. Researchers combined results from 12 studies involving 715 babies and toddlers. They found that these very early interventions didn't significantly improve autism symptoms, thinking skills, or language development by age 3 compared to usual care. The evidence suggests that starting interventions extremely early may have limited benefits for developmental outcomes.

This systematic review and meta-analysis examined the effectiveness of very early autism interventions for infants and toddlers under 24 months. Analyzing 12 studies with 715 participants, researchers found low to moderate certainty evidence that these interventions did not produce significant improvements in autism symptoms, cognitive development, or language skills by age 3 years. Clinician-assessed measures showed no meaningful differences between intervention and care-as-usual groups across multiple domains including ADOS severity scores and developmental assessments. Neurocognitive outcomes from EEG and eye-tracking studies were inconsistent and heterogeneous, making conclusions difficult.

Results suggest very early interventions before 24 months may have limited immediate developmental impact. Clinicians should consider that benefits may emerge later or require modified approaches. This doesn't negate intervention value but suggests realistic expectations about early outcomes and potential need for sustained, longer-term support.

The study notes heterogeneous neurocognitive outcomes and inconsistent findings across studies. Sample sizes and intervention approaches varied across the included studies, which may have affected the ability to detect treatment effects.

The aim of this systematic review was to determine the efficacy of very early interventions for infants and toddlers at increased likelihood of or diagnosed with autism for autism symptomatology, developmental outcomes and/or neurocognitive markers. Eight databases were searched (14 April 2022) with inclusion criteria: (i) RCTs with care as usual (CAU) comparison group, (ii) participants at increased likelihood of or diagnosed with autism and aged <24 months corrected age (CA), (iii) parent-mediated and/or clinician directed interventions, and (iv) outcome measures were autism symptomatology, cognition, language, adaptive skills, or neurocognitive assessments (EEG and eye tracking). Quality was assessed using Risk of Bias 2 and GRADE. Nineteen publications from 12 studies reported on 715 infants and toddlers.

There was low to moderate certainty evidence that clinician-assessed outcomes did not show significant treatment effects for: autism symptomatology (ADOS CSS: MD -0.08, 95% CI -0.61, 0.44, p = 0.75), cognitive outcome (Mullen Scales of Early Learning-Early Learning Composite (MSEL-ELC): SMD 0.05, 95% CI -0.19, 0.29, p = 0.67), receptive language (MSEL-Receptive Language: SMD 0.04, 95% CI -0.21, 0.3, p = 0.74) or expressive language (MSEL-Expressive Language: SMD 0.06, 95% CI -0.1, 0.23, p = 0.45). Neurocognitive outcomes (EEG and eye tracking) were heterogeneous, with inconsistent findings. There is low to moderate certainty evidence that very early interventions have limited impact on neurodevelopmental outcomes by age 3 years.