Table 1.

Assessment, demographic, cognitive-language, and speech information for participants in six groups of children in six USA cities recruited for idiopathic SD. The groups are listed in descending order by the number of participants in each original sample. Cell values and percentages for demographic, cognitive-language, and speech variables are for the 415 of the original 448 (93.5%) participants that were able to be classified using the SDCSS.

	Assessment			Demographic				Cognitive-Language				Speech
	Original Group	SDCSS Classified		Age (yrs)		Sex (%)		Cognitiona		Languageb		PCCc		IId
Group	n	n	%	M	SD	% Female	% Male	M	SD	M	SD	M	SD	M	SD
Idiopathic SD
Group 1	200	188	94.0	4.4	1.1	33.5	66.5	109.4	13.3	99.1	10.5	69.5	12.0	91.3	8.1
Group 2	84	72	85.7	4.0	0.7	26.4	73.6	*	*	*	*	70.0	9.6	88.5	8.9
Group 3	71	67	94.4	5.1	1.5	22.4	77.6	96.3	12.8	95.3	14.5	80.6	11.2	94.4	7.2
Group 4	26	26	100.0	7.8	1.1	30.8	69.2	104.7	12.6	95.0	20.2	89.8	7.1	97.3	2.7
Group 5	22	21	95.5	5.5	0.6	23.8	76.2	*	*	*	*	82.8	6.1	91.7	12.2
Group 6	45	41	91.1	6.2	2.6	19.5	80.5	*	*	*	*	77.5	11.4	86.8	11.0
Total	448	415	93.5	5.5	1.3	26.1	73.9	103.5	12.9	96.5	15.1	78.4	9.6	91.7	8.4

Notes: SD = Speech Delay; SDCSS = Speech Disorders Classification System Summary; PCC = Percentage of Consonants Correct; II = Intelligibility Index, * = no data.

^aStandard scores for IQ Composite: Kaufman Brief Intelligence Test – Second Edition; Kaufman and Kaufman (2004). IQ Scores: Stanford-Binet-4^th Edition; Thorndike, Hagen, and Sattler (1986).

^bStandard scores for Oral Composite: Oral and Written Language Scales (OWLS); Carrow-Woolfolk (1995). Standard scores for Core Language: Clinical Evaluation of Language Fundamentals-4 (CELF–4); Semel, Wiig, and Secord (2003).

^cShriberg et al. (1997).

^dShriberg (1993).