Predicting motor outcome at preschool age for infants tested at 7, 30, 60, and 90 days after term age using the Test of Infant Motor Performance

Abstract

Background and purpose: Accurate and diagnostic measures are central to early identification and intervention with infants who are at risk for developmental delays or disabilities. The purpose of this study was to examine (1) the ability of infants' Test of Infant Motor Performance (TIMP) scores at 7, 30, 60 and 90 days after term age to predict motor development at preschool age and (2) the contribution of the home environment and medical risk to the prediction.

Subjects and methods: Sixty-one children from an original cohort of 90 infants who were assessed weekly with the TIMP, between 34 weeks gestational age and 4 months after term age, participated in this follow-up study. The Peabody Developmental Motor Scales, 2nd edition (PDMS-2), were administered to the children at the mean age of 57 months (SD=4.8 months). The quality and quantity of the home environment also were assessed at this age using the Early Childhood Home Observation for Measurement of the Environment (EC-HOME). Pearson product moment correlation coefficients, multiple regression, sensitivity and specificity, and positive and negative predictive values were used to assess the relationship among the TIMP, HOME, medical risk, and PDMS-2 scores.

Results: The correlation coefficients between the TIMP and PDMS-2 scores were statistically significant for all ages except at 7 days. The highest correlation coefficient was at 90 days (r=.69, P=.001). The TIMP scores at 30, 60, and 90 days after term; medical risk scores; and EC-HOME scores explained 24%, 23%, and 52% of the variance in the PDMS-2 scores, respectively. The TIMP score at 90 days after term was the most significant contributor to the prediction. The TIMP cutoff score of -0.5 standard deviation below the mean correctly classified 80%, 79%, and 87% of the children using a cutoff score of -2 standard deviations on the PDMS-2 at 30, 60, and 90 days, respectively.

Discussion and conclusion: The results compare favorably with those of developmental tests administered to infants at 6 months of age or older. These findings underscore the need for age-specific test values and developmental surveillance of infants before making referrals.