Discussion
The purpose of this systematic review was to meta-analyze single-case studies that utilized high-tech SGDs with children with ASD between the ages of 0 to 8 years. Based on IRD scores, high-tech SGDs are strongly effective to teach singlestep manding, multistep manding, multistep tacting, and multistep intraverbal to children with ASD. The findings also show that high-tech SGDs as a communication intervention has moderate effects on single-step tacting and weak effects on vocal production in children with ASD. Another purpose of this review was to evaluate the included studies based on Horner et al.'s (2005) quality indicators for single-case research and to determine the level of evidence for using high-tech SGDs with children with ASD. Only two studies reflected high quality (Flores et al. 2012; Strasberger and Ferreri 2014), whereas 16 studies reflected acceptable quality (Achmadi et al. 2014; Couper et al. 2014; Gevarter et al. 2014, 2016; King et al. 2014; Lorah et al. 2013, 2014; Lorah 2016; Lorah and Parnell 2017; McLay et al. 2015; Schlosser et al. 2007; Sigafoos et al. 2013; Strasberger and Ferreri 2014; van der Meer et al. 2012a, b, c). Based on the decision rules developed by Test et al. (2009), a moderate level of evidence was established for using high-tech SGDs as a communication intervention for children with ASD.
