Limitations of the study
Before commencing the study, it would have been preferable to conduct an inter-rater reliability study with the involved testers, both for the AIMS and the PDMS-2. The six testers were all physiotherapists working in paediatrics, with experience using the AIMS, whereas the use of PDMS-2 was new to the physiotherapists in two of the hospitals, which might have affected the scoring.Infants in this study were a sample of convenience (The abovementioned limitations should be considered when generalizing the results of this study to other infants born preterm. A Rasch analysis on the AIMS showed a ceiling effect when assessing infants after the age of 9 months, because of fewer items on the test and thus lower precision for differentiating among infants [