3.3.1. Module 2 Items

Between-group comparisons of algorithm items on Module 2 of the ADOS-2 revealed 7 items in the SA domain and 3 items in the RRB domain that differentiated participants with DS + ASD from participants with DS-only (see Figure 3). The differences on all of these items remained significant after the FDR correction. More specifically, differences in group mean ranks were detected for SA algorithm items measuring: (1) descriptive, conventional, instrumental or informational gestures (U = 160.50; *p* = 0.012); (2) unusual eye contact (U = 108.00; *p* < 0.001); (3) facial expressions directed to others (U = 122.00; *p* = 0.001); (4) showing (U = 74.50; *p* < 0.001); (5) quality of social overtures (U = 133.50; *p* = 0.002) ; (6) amount of reciprocal social communication (U = 157.50; *p* = 0.017); (7) overall quality of rapport (U = 92.50; *p* < 0.001). Additionally, differences in group mean ranks were detected for RRB algorithm items measuring: (1) stereotyped/Idiosyncratic use of words or phrases (U = 172.50; *p* = 0.029); (2) hand and finger and other complex mannerisms (U = 188.50; *p* = 0.002); (3) unusually repetitive interests or stereotyped behaviors (U = 150.50; *p* = 0.007).
