Reaching and grasping a moving object in 6-, 8-, and 10-month-old infants: Laterality and performance

Abstract

The goal of this study was to investigate some of the visuo-motor factors underlying an infant’s developing ability to grasp a laterally-moving object. In particular, hand preference, midline crossing, and visual-field asymmetry were investigated by comparing performance as a function of the object’s direction of motion. We presented 6-, 8-, and 10-month-old infants with a graspable object, moving in a circular trajectory in the horizontal plane. Six-month-old infants reached for the object with the ipsilateral hand and grasped it with the contralateral hand. Eight-month-old infants showed a strong right-hand bias for both reaching and grasping. Ten-month-old infants showed a greater diversity of strategy use including bimanual and successful ipsilateral grasping following ipsilateral reaching in both directions of motion. Thus, motor constraints due to spatial compatibility, hand preference and bimanual coordination (but not midline crossing) must be taken into account to understand age differences in grasping a moving object.

Early reach to grasp development of infants with asymmetric brain injury on the Grasp and Reach Assessment of Brisbane (GRAB)

“…32,34,157 ). Specifically, some studies have examined movement speed and movement quality during reaching using kinematic analysis 32,157 and have measured the number of reaches towards a vertically moving toy (e.g.…”

“…32,34,157 ). The present study confirmed this finding as the majority of healthy, term-born infants demonstrated a similar frequency of unimanual contacts and grasps between ULs.…”

“…21,34,35 In studies examining simple grasping of objects in infants, laterality or hand preference does not appear to be strong initially and often varies between right, left and no preference. 36,37 Switching hands while manipulating an object happens early in motor development, prior to six months of age.…”

“…Previous studies have examined and described: (i) the development of reach and grasp skills of healthy, term-born infants (e.g. 30,34,40,96,157,179,180 ); (ii) the early development of reaching in preterm infants (< 33 weeks gestational age; GA) compared to healthy, term-born infants 109,181 ; and (iii) the early development of UL behaviours in infants with neonatal stroke compared to healthy, term-born infants (< eight months C.A. 83,177 ).…”

“…Behavioural coding is commonly utilised in infant studies to monitor and quantify behaviours of interest, such as upper limb reaching (e.g. 21,24,32,34,35,109,177,178 ). The GRAB was developed to address a gap in the literature to quantify and evaluate the symmetry of emerging reach and grasp behaviours between ULs in very young infants with asymBI compared to typically developing infants.…”