Imagination exercises improve language in younger but not in older children with autism suggesting a strong critical period

Imagination exercises administered by caregivers were investigated in a three-year-long observational trial of 3,540 children with autism aged 2-12 years. Tablet-based verbal and nonverbal exercises modeled on language therapy and emphasizing mental-juxtaposition-of-objects were organized into an application called Mental Imagery Therapy for Autism (MITA). MITA-exposed children were matched to the ‘Treatment-as-Usual’ participants (TaU, N=5,222) by age, gender, language, sociability, cognitive awareness, health, and ASD severity at baseline. Both younger (2-5 years-of-age) and older children (5-12 YOA) in MITA and TaU groups improved their symptoms over time, but younger MITA-exposed children showed 2.3-fold improvement in language score at the end of the trial vs. TaU group. There was no difference between MITA and TaU in the older children group, supporting Lenneberg’s critical period hypothesis.