LAUSR

“How should I apply this information?” Pediatric therapists use normative data to help determine whether a child differs from his/her peers. This is the second study with Dutch infants that use the Alberta Infant Motor Scale (AIMS)1 to assess the gross motor development. Unlike the first study conduct by Fleuren et al2 that compared percentile ranks, this study used a logistic regression method, as suggested by Darrah el al.3 It calculates the item location (places each AIMS item on the age scale), reflecting the age at which 50% of the infants passed the item. Although different analyses, the 2 studies had similar results, with the Dutch infants passing the majority of the AIMS items at a later age, compared with the Canadian group. Despite the observed difference in 41 of 45 items, the magnitude of the range from 0.01 to 14.42 weeks suggests that some of these differences may not be clinically relevant. In 14 of 41 (34%) items, the 2 groups differed by 3 weeks or less. Differences of 0.49 or 0.01 weeks although statistically significant may not be clinically relevant. The magnitude of the differences also varied across test positions. All supine items differed 0 to 3 weeks, while 7 of the 11 standing items differed more than 10 weeks. Clinicians would benefit from information that considers the magnitude of the item differences. Also, what would an AIMS item clinically relevant difference size be that might impact Dutch infants’ rate of development? “What should I be mindful about when applying this information?” The sequence of development was similar between Dutch and Canadian infants indicating that motor milestones emerge in the same developmental order. Although the authors conclude that Dutch infants acquire gross motor skills at a later age, they do not explore differences between groups that are clinically relevant. Evidence from cross-cultural studies is most valuable to help therapists understand what aspects of child development may be universal and what are culture specific. Knowledge regarding the mechanisms (ie, specific parental practices) underlying the observed differences and how they may impact the time of acquisition of Dutch infants’ gross motor skills will help guide clinical practice.