Comparison of test of infant motor performance (TIMP) item responses among children with cerebral palsy, developmental delay, and typical development.

Impairment of children's motor performance might limit participation in family and community life. Therefore, identification of motor impairments is important in support of early intervention to prevent limitations in children's occupational performance. The purpose of this paper is to examine item performance on the Test of Infant Motor Performance (TIMP) in a group of infants later diagnosed as having cerebral palsy (CP), developmental delay, or typical development. Particularly, we aimed to determine if specific TIMP items have a strong relationship at particular ages with the presence of a later diagnosis of CP. Exploratory graphic representation and Rasch differential item analysis were employed to investigate each individual TIMP item's behavior in discriminating among children with different outcomes. Items discriminating among the three outcome groups included: hand to mouth, neck control, rolling, and pull to sit items, particularly at ages term, 9 weeks, and 12-13 weeks corrected age. Children with CP presented "advanced" performance in items using extension patterns and slow development or regression in items requiring antigravity and balanced used of flexion-extension patterns of muscle activity.