“…One common feature is severe communication difficulties. In particular, expressive communication is severely affected, and approximately 80% of individuals diagnosed with Rett syndrome lack speech (Bartolotta, Zipp, Simpkins, & Glazewski, 2011;Didden et al, 2010;Urbanowicz, Downs, Girdler, Ciccone, & Leonard, 2015). Even so, a number of studies have found that people with Rett syndrome enjoy social interaction (Fabio, Giannatiempo, Oliva, & Murdaca, 2011;Sandberg, Ehlers, Hagberg, & Gillberg, 2000;Urbanowicz, Downs, Girdler, Ciccone, & Leonard, 2016), and that the most efficient form of communication is eye pointing (Bartolotta et al, 2011;Didden et al, 2010).…”