Concurrent Validity of the TIMP and the Bayley III Scales at 6 Weeks Corrected Age

Purpose: Examine agreement between the Test of Infant Motor Performance (TIMP) and the Bayley III. Methods: One hundred forty-five infants born at 29 to 34 weeks gestation with socioenvironmental risk factors were tested on the TIMP and Bayley III at 6 weeks corrected age (CA). Scores were correlated to assess convergence/divergence of content. Decision analysis using a cutoff of the mean on the Bayley Motor Composite and -0.5 and -1 SD from the mean on the TIMP assessed agreement on delay/nondelay. Results: The TIMP-Bayley Motor Composite correlation was 0.546, with Cognitive was 0.310, and with Language was 0.281. Nine percent of infants scored less than -1.0 SD on the TIMP, while no child scored less than -1 SD on the Bayley Motor scale (sensitivity, 31%). Conclusions: Convergent validity between the TIMP and the Bayley Motor scale was demonstrated, but no infant showed delay on any Bayley scale. The TIMP is preferred for early assessment of infants.