The High Quality Communication intervention aims to stimulate interpersonal communication between individuals with congenital deaf-blindness (CDB) and their social partners. Found effective in multiple-case experiments, the intervention is based on Trevarthen's theory of intersubjective development (Bråten & Trevarthen, 2007), which describes children's innate and developing ability to share subjective states in interpersonal communication and social partners' mediating role in this development. One implication of this theory is that social partners can support the emergence of higher-complexity communication behaviors in individuals who are still developing these behaviors. To test this proposition, communication patterns between individuals with CDB and their parents, teachers, and professional caregivers were analyzed. Analysis of two-event sequences of communicative behaviors showed a highly significant correspondence between the behavior of the social partner and the subsequent behavior of the individual with CDB, confirming that social partners can scaffold higher-complexity communication within interpersonal communication.