Table 2.

Communicative functions observed (●) or not observed (□) for each child between 9 and 12 months of age and later diagnosed with typical RTT. Categories according to the Inventory of Potential Communicative Acts (IPCA; Sigafoos et al., 2000a, 2006).

	Social convention	Attention to self	Reject/Protest	Request Object	Request Action	Request Information	Comment	Choice Making	Answer	Imitate	Total
Child 1	□	●	□	□	□	□	●	□	●	□	3
Child 2	□	●	●	●	●	□	●	□	●	●	7
Child 3	●	●	●	□	□	□	●	□	●	●	6
Child 4	□	●	●	●	□	□	□	□	●	□	4
Child 5	●	●	□	□	□	□	●	□	●	●	5
Child 6	●	●	●	●	□	□	●	□	●	□	6
Total	3	6	4	3	1	0	5	0	6	3