Brief Report: Modest but Clinically Meaningful Effects of Early Behavioral Intervention in Twins with Rett Syndrome-A Case Study.

Titlestad et al. (2019) tracked twin preschool girls who have Rett syndrome. The girls received early intensive behavioral intervention (EIBI) for three years. The team watched their communication and self-help skills over time.

After three years the twins showed modest but real gains in daily skills. They could ask for items more often and feed themselves better. The authors call the change “clinically meaningful” even though it was not large.

Most EIBI reviews, like Howlin et al. (2009) and Rodgers et al. (2021), show bigger IQ and adaptive jumps in kids with autism. Those studies pool hundreds of children and report medium-to-large effects.

Eldevik et al. (2010) also saw large gains, but their preschoolers had only general intellectual disability and got just 10 hours per week. The twins in Berg’s study had Rett syndrome and still improved, showing EIBI can help outside the autism label.

Short Rett-only trials such as Bertapelli et al. (2016) and Mammarella et al. (2022) used brief cognitive tasks and still found positive EEG or gaze changes. Berg’s long EIBI case lines up with these: even brief or modest interventions can move the needle for Rett, and longer ABA may add real-life skills.

If you serve a child with Rett, do not assume ABA is off the table. These twins prove steady, play-based teaching can sharpen communication and self-care. Start early, keep intensity reasonable, and track small weekly wins. Share clips of progress with parents so they stay motivated to practice at home.