Validity of the Test of Infant Motor Performance for discriminating among infants with varying risk for poor motor outcome

Objective: The objective was to assess the ability of the Test of Infant Motor Performance (TIMP) to discriminate among infants with varying degrees of risk for motor developmental morbidity on the basis or perinatal medical complications. Study design: Ninety-eight infants were tested weekly with the TIMP until 4 months of age. Comparisons were made among 5 groups of infants: (1) term infants without significant medical problems (low risk); (2) infants born prematurely with no significant medical problems (medium risk); (3) infants born at < 30 weeks' gestational age or with birth weight < 1500 g (high risk); (4) infants with chronic lung disease (high risk); and (5) infants with brain insults (high risk). A random-effects growth curve analysis assessed differences between the groups in slope and level of development across time. Results: Infants in the low- and medium-risk groups did not differ from each other but were significantly better performers than infants in the highrisk groups. Infants with brain insults performed significantly less well than all other infants, both in absolute level of performance and in developmental slope across time. Performance by black infants averaged 2 points higher than that of other infants. Conclusions: The TIMP can discriminate among infants with differing risks for motor developmental delay.