. Author manuscript; available in PMC: 2013 Jul 26.

Published in final edited form as: J Child Neurol. 2012 Jan;27(1):22–29. doi: 10.1177/0883073811424462

Table 1.

Sample derivation

	Yes	No
Enrolled	1506
Had the 3^rd (“late”) protocol head ultrasound scan	1260	241
Had the 1^st &/or 2^nd protocol head ultrasound scan	1171	89
Survived to 2 years	1064	107
Had one or more of the 4 evaluations below^*	949	115
Had a neurologic exam (CP diagnosis) at 2 years	937	12
Had a Bayley assessment (MDI and PDI) at 2 years	904	15
Had a head circumference measurement at 2 years^**	824	125
Information about visual dysfunction available at 2 years	939	10

All numbers below are subtracted from 949

^**

And had a birth head circumference Z-score > -2

Abbreviations: CP – cerebral palsy; MDI – Mental Development Index; PDI – Psychomotor Development Index