JASPER Intervention in Down Syndrome

The goal of this study is to determine whether JASPER (Joint Attention, Symbolic Play, Engagement, Regulation), which is an intensive, targeted early behavioral intervention focused on a developmentally based approach for teaching joint engagement, joint attention, and play skills can improve behavioral / emotional regulation, social communication skills, and developmental trajectories in Down syndrome (DS). The investigators will also explore the potential use of EEG and event-related potentials (ERP) as outcome measures, as this approach may help elucidate mechanisms of change in behavior and development, and may help explain differences in development of social communication skills in individuals with DS. EEG and ERP measure may also help to predict treatment outcome.

Inclusion Criteria:

* Confirmed diagnosis of Trisomy 21
* Age 24-48 months
* Able to walk independently across a room
* Uses at least 5 words / signs
* English speaking
* Parent able to accompany participant to all study visits

Exclusion Criteria:

-Diagnosis of Mosaic / Translocation Down syndrome