“…There were limitations in the analyzed studies: some studies limited to one category of ASD or use small sample size (Barber et al, 2016;Radley et al, 2015Radley et al, , 2017Ventola et al, 2014;Vivanti et al, 2014;Waugh & Peskin, 2015;Chang et al, 2016). Besides, some studies did not have a control group (Barber et al, 2016;Radley et al, 2015Radley et al, , 2017Reis et al, 2018;Ventola et al, 2014;Fava et al, 2011;Colombi et al, 2018), or not randomly assigned (Zachor & Ben Itzchak, 2010;Waugh & Peskin, 2015). Furthermore, participants in some study were receiving other intervention or services besides the implementation of the intervention program (Reis et al, 2018), or the external factor e.g.…”