TABLE 1.

Infant characteristics

Group	Number	Test ages	Gender (F, M)	Ear (L, R)
Group 1
Cross-sectional	35	P1 = 31–33 wks PCA	20, 15	13, 22
	28	P2 = 34–36 wks PCA	13, 15	19, 9
	62	P3 = 37–40 wks PCA	35, 27	38, 24
	118	Term	48, 70	70, 48
	18	4.5 wks of age	9, 9	7, 11
Group 2
Longitudinal preterm	9	33–40 wks PCA (testing at weekly intervals)	4, 5	6, 3
Group 3
Longitudinal postnatal	20	Birth, 3, 4, 5, and 6 mo	9, 11	11, 9
Total	290