Table 1.

Distributions of observed versus expected numbers of combinations of cognitive impairments in preterm and control children

	Preterms		Controls
	Observed	Expected	Observed	Expected
None	33 (55%)	26.1 (43.6%)	97 (81%)	94.2 (78.5%)
One impairmenta	18 (30%)	20.2 (33.7%)	19 (16%)	23.5 (19.6%)
Two impairmentsa	4 (7%)	11.6 (19.3%)	3 (3%)	2.2 (1.8%)b
Three impairments and overa	5 (8%)	2.0 (3.4%)	1 (1%)	0.1 (0.2%)b
P-value	0.01		0.35b
Cohen’s W	0.43		0.13b

^aRefer to abnormal (< 5th percentile) test scores

^bTwo highest categories have been combined for statistical testing