Background: Intensive Interaction is a social communication intervention for persons with profound intellectual and multiple disabilities. The goal of Intensive Interaction is to establish human connectedness and improve communication. The aim of this thesis was to determine the effect of Intensive Interaction on preverbal communication and cortical brain activity.
Method: This multimethod study consisted of Phase 1, the pre-experimental phase, consisting of Study 1 and Phase 2, and the experimental phase, consisting of Studies 2 and 3. Study 1 examined the evidence for Intensive Interaction through a scoping review. Study 2 aimed to determine the effect of Intensive Interaction on preverbal communication using a multiple probe across participant design. Study 3, used an interrupted time series design, aimed to determine the effect of Intensive Interaction on cortical brain activity, measured as the relative concentration of oxygenated haemoglobin in the dorsolateral prefrontal cortex using functional near-infrared spectroscopy, in persons with profound intellectual and multiple disabilities.
Results: The scoping review highlighted that studies on Intensive Interaction should improve intervention reporting strategies and uniformity in the definition and measurement of its outcomes. Findings from the multiple probe design indicate participant gains in preverbal communication during Intensive Interaction. Measurement of cortical brain activity using functional near-infrared spectroscopy indicate a decrease in dorsolateral prefrontal cortex activity over time.
Keywords: cortical brain activity, dorsolateral prefrontal cortex, Fundamentals of Communication, functional near-infrared spectroscopy, Intensive Interaction, multiple probe across participant design, preverbal communication, profound intellectual and multiple disabilities