Tests & Measures: A Resource for Pediatric Physical Therapy Practitioners

Reaching in infants: Segmental Assessment of Trunk Control Article Summary

Title: Segmental Trunk Control Acquisition and Reaching in Typically Developing Infants

Authors: Jaya Rachwani, Victor Santamaria, Sandra L. Saavedra, Stacy Wood, Francine Porter, and Marjorie H. Woollacott1

Citation: Rachwani J, Santamaria V, Saavedra SL, Wood S, Porter F, Woollacott MH. Segmental Trunk Control Acquisition and Reaching in Typically Developing Infants. Exp Brain Res Exp Hirnforsch Exp Cerebrale. 2013;228(1):131-139. doi:10.1007/s00221-013-3544-y

Purpose: The purpose of this study was to understand the influence of external support at the thoracic and pelvic levels of the spine on functional reaching development.

Study Population/Methods: There were 17 full-term infants aged 4-6 months that participated in this study (9 males to 8 females). Participants were recruited via flyers in various day care centers in Oregon, USA. The infants were separated into 2 groups after being assessed with the SATCo (Segmental Assessment of Trunk Control) and AIMS (Alberta Infant Motor Scale) to determine level of trunk control and gross motor function, respectively. Group 1 consisted of infants with a score of 4-5 on the SATCo and Group 2 consisted of infants with a score of 6-7 on the SATCo. Additionally, at this one-time assessment, parents responded to a health questionnaire about their infant. The reach test consisted of the evaluator presenting the toy 15 times while the child was supported at the thoracic level then another 15 times when supported at the pelvis (or vice versa). Sensors were placed on both the infant and the bench upon which they were sitting in order to gather kinematic data.

Results: This study found that, with thoracic support, there were no significant differences in any variables assessed during reaching. Both groups showed similar stability in the position and trajectory of reaching. However, with pelvic support, significant differences were found between the groups. Group 1 infants, who had not yet developed control of the thoracic and lumbar spine, showed increased time to reach object as well as increased head and trunk displacement compared to Group 2 infants, who had acquired thoracic and lumbar spine control.

Major Strengths/Limitations: The article mentioned preventing fatigue/training effects by alternating start positions on the infants with half of them starting with pelvic support and the other half starting with thoracic support which I think is a strength. Additionally, the researchers started each reach test with a specific colorful toy to gain the infants attention but were able to switch toys to maintain engagement which I found beneficial. Limitations to the study were the relatively small sample size of 17 infants and the use of sensors for kinematic data gathering. I found the sensors to be a limiting factor because reaching was not assessed without the sensors attached to the infants. I would have liked to see how performance differed without a new stimulus attached to them.

Conclusion: There is a high correlation between reaching performance and acquisition of segmental trunk control. Now, there is a need to investigate if this correlation is comparable to reaching performance in non-typically developing infants.