Reliability and concurrent validity of the Infant Motor Profile

Aim The Infant Motor Profile (IMP) is a qualitative assessment of motor behaviour in infancy. It consists of five domains: movement variation, variability, fluency, symmetry, and performance. The aim of this study was to assess interobserver reliability and concurrent validity of the IMP with the Alberta Infant Motor Scale (AIMS) and an age-specific neurological examination. Method Fifty-nine preterm infants (25 females, 34 males; median gestational age 29.7wks, median birthweight 1285g) and 146 term infants (74 females, 72 males; median gestational age 40.1wks, birthweight 3500g) were included. Assessments were performed at corrected ages of 4, 6, 10, 12, and 18months and consisted of the IMP, AIMS, and an age-specific neurological examination. Interobserver reliability was investigated on a sample of 25 video recordings. Non-parametric statistics were used to analyse the data. Results Interobserver reliability was high (intraclass correlation coefficient 0.95). At all ages, AIMS scores correlated weakly to fairly with total IMP scores (Spearman's 0.360.55), but moderately to strongly with scores on the performance domain of the IMP (Spearman's 0.470.84). A clear relation was found between total IMP score and outcome of the neurological examination (KruskalWallis p<0.001 at all ages). Interpretation Interobserver reliability of the IMP is good. Concurrent validity with the AIMS is best for the IMP performance domain. Concurrent validity with age-specific neurological examination is very good.