Construct Validity of the Test of Infant Motor Performance

Abstract

The purpose of this study was to assess the construct validity of the Test of Infant Motor Performance (TIMP), specifically the test's sensitivity for assessing age-related changes in motor skill and correlation with risk for developmental abnormality. Subjects were 137 term and preterm infants stratified by postconceptional age, medical complications score on the Problem-Oriented Perinatal Risk Assessment System, and ethnicity and race (non-Latino Caucasian, African-American, and Latino). Subjects were tested on the TIMP at ages ranging from 32 weeks postconceptional age to 3.5 months past term-equivalent age. Scores (Rasch logit ability measures) were correlated with postconceptional age. A multiple regression analysis was used to assess the contributions of age, risk, and ethnicity to the variance in TIMP scores. The correlation between postconceptional age and TIMP performance measures was .83. Risk and age together explained 72% of the variance in TIMP performance (R = .85, P < .00001). No differences related to ethnicity were found. The TIMP has validity for assessing age-related development of functional motor skills in young infants and is sensitive to risk for poor developmental outcome.