Additional Weight Influences the Reaching Behavior of Low-Risk Preterm Infants

ABSTRACT

The authors investigated the influence of additional weight in the reaching behavior of preterm infants. Nine low-risk preterm and 10 full-term infants age 5–7 months participated. A toy was presented in two procedures: (a) baseline and (b) additional weight (bracelet with weight of 20% of the infant's upper limb mass). The additional weight reduced the straightness index at 5 months, increased the mean velocity and decreased the movement units at all months, and increased unsuccessful grasps at 5 and 7 months in preterm infants. Preterm infants showed less movement units at all months and less unsuccessful grasps at 6 months compared with full-term infants. Weight disturbance seems to change the intrinsic dynamics involved in reaching movements of 5–7-month-old preterm infants.

Keywords:

• hand
• kinematics
• load
• motor control

ACKNOWLEDGMENTS

The authors would like to thank parents and infants for participating in the study. They also thank Ana Letícia Sarkis Rossi, physiotherapy student at the Federal University of São Carlos, for her support during the initial version of this manuscript. Aline Martins de Toledo received financial support from the Coordination of Improvement of Higher Education Personnel (CAPES, Brazil). The study was supported by the São Paulo Foundation for Research Support (FAPESP, Brazil).