Inter- and Intrarater Reliability of the Infant Motor Profile in 3-to 18-Month-Old Infants

PURPOSE: To investigate inter- and intrarater reliability scoring the Infant Motor Profile (IMP).METHODS: A total of 20 infants at risk for motor developmental delay were assessed using the IMP. Six infants were born at term (gestational age: 38-42 weeks), and 14 infants were preterm (gestational age: 24-35 weeks). Videos were analyzed twice with an interval of 1 month by 4 assessors after 2 days of IMP training.RESULTS: Spearman rank scores demonstrated strong interrater and intrarater reliability for total IMP scores (inter: r = 0.80-0.96; intra: r = 0.85-0.97) and the domain of performance (r = 0.95-0.99). Reliability for the domains of variation, variability, and fluency was satisfactory (inter: r = 0.15-0.85; intra: r = 0.30-0.92). The weakest agreement was found in the domain of symmetry (inter: r = 0.20-0.69; intra: r = 0.33-0.65).CONCLUSION: Therapists naive to the IMP demonstrate good intra and interrater reliability (after 2 days of training) for most domains with the exception of symmetry.