Table 2.

Mental and motor performance scores as assessed with Bayley's scales of Infant Development in HT1 at 6 to 42 months of age.

Age at testing
Test	6–16 months	16–26 months	28–42 months
	(N = 6)	(N = 7)	(N = 8)
MDI	84 ± 23	80 ± 17	77 ± 20
PDI	69 ± 17	74 ± 16	85 ± 20
MDI < 70	2 (33%)	2 (29%)	3 (38%)

MDI: mental development index; PDI: performance development index (mean ± SD).