Assessing progress and outcome of early intensive behavioral intervention for toddlers with autism.
Starting EIBI before age two gives the sharpest one-year jump in joint attention, play, and language, especially when early vocal imitation clicks fast.
01Research in Context
What this study did
Giallo et al. (2014) watched toddlers with autism for one full year of Early Intensive Behavioral Intervention.
They used direct tests to track joint attention, play, imitation, language, and stereotypy every few months.
Kids who began before their second birthday formed the key group.
What they found
After twelve months every child improved on joint attention, play, and imitation.
Language scores also rose while repetitive actions dropped.
The youngest starters made the biggest leaps in every area.
How this fits with other research
Eldevik et al. (2026) pooled fifteen similar studies and found the same pattern, so this single cohort lines up with a mountain of data.
Ben-Itzchak et al. (2007) and Klintwall et al. (2015) add a twist: children who enter with higher IQ or milder social delays still move faster, so age is not the only clock to watch.
Guthrie et al. (2023) ran a parent-training RCT and also saw the 18-month edge over 27-month starts, backing the “earlier is better” rule with tighter design.
Why it matters
You now have three clear signals: start before age two, watch baseline IQ and social level, and track early vocal imitation. If a toddler masters imitation and labeling in the first three months, keep pushing; if not, adjust intensity or add parent coaching. Use these mileposts to decide when to fade or extend hours, and share the timeline with families so they know why every session counts.
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02At a glance
03Original abstract
Intensive behavioral intervention for young children diagnosed with autism can produce large gains in social, cognitive, and language development. Although several studies have identified behaviors that are possible indicators of best outcome, changes in performance are typically measured using norm-referenced standardized scores referencing overall functioning level rather than via repeated observational measures of autism-specific deficits (i.e., social behavior). In the current study, 83 children with autism (CWA), aged 1, 2 and 3 years, and 58 same-aged typically developing children (TDC) were directly observed in the areas of cognitive skills, joint attention (JA), play, and stereotypic behavior using a measure called the Early Skills Assessment Tool (ESAT; MacDonald et al., 2006). CWA were assessed at entry into an EIBI program and again after 1 year of treatment. Changes in performance were compared pre- and post-treatment as well as to the normative data by age. Results indicate significant gains on the ESAT across all age groups with the greatest gains seen in the children who entered treatment prior to their second birthday. Increases were seen on direct measures of JA, play, imitation and language while decreases were seen in stereotypy regardless of level of performance at entry into EIBI. The ESAT, a direct measurement tool, served as a sensitive tool to measure changes in autism symptomatology following EIBI treatment.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2014.08.036