In-hand manipulation in young children: translation movements.

OBJECTIVE: The purpose of this study was to look at the development of in-hand translation skills in young children; that is, the child's ability to move a small object from the fingers into the palm and from the palm to the fingers. Three questions were asked: (a) Do boys' and girls' performance differ significantly? (b) Does the performance of the children improve with age? and (c) Can periods of rapid improvement with age be seen on the tasks presented? METHOD: In-hand manipulation translation was measured with a pegboard task for 154 right-handed children between 3-0 years and 6-11 years of age and 13 adults. Participants were videotaped as they picked up two to five pegs, one at a time; stored them in the hand; and moved the pegs out of storage to place them in the pegboard. The number of pegs handled in each trial as well as the methods used to move the peg to and from the palm were recorded. RESULTS: Boys and girls did not show significant differences in their performance, but when slight differences did occur, they favored the girls. Age was found to be a significant factor in both the number of pegs handled and the method used in handling them. The older children tended to place more pegs successfully and were more likely to use the methods most commonly used by the adults. A major finding was the marked difference in how the children solved the problem of moving the peg in and out of the palm compared with the adults. The adults used gravity to assist the movement of the peg; the children tended to use methods that allowed them to maintain contact with the peg throughout the movement. CONCLUSION: In-hand manipulation translation skills appear to have a long developmental course. Children are closer to adults in their ability to perform the task than in the methods that they use. This study shows the importance of observing how children perform tasks, not just whether they complete the tasks. Differences in the methods used help to determine efficiency. Observation of these skills in children may expand a therapist's understanding of children's fine motor abilities.

In-hand manipulation in young children: rotation of an object in the fingers.

OBJECTIVE: The purpose of this study was to look at the development of two in-hand skills of rotation. Three questions were asked: (a) Do boys' and girls' performance differ significantly? (b) Does performance improve with age? and (c) Can periods of rapid improvement with age be seen on the tasks presented? METHOD: The in-hand manipulation skill of rotation was measured in 154 right-handed children between the ages of 3-0 years and 6-11 years as well as in 13 adults. The participants were videotaped as they either turned over small pegs in a pegboard or rotated a peg in their fingertips. The number of pegs dropped when turning and placing them back in the board, the number of times a peg could be rotated in the fingertips, the time it took to complete each task, and the methods participate used to accomplish the two tasks were recorded from the videotapes. RESULTS: The results indicated no differences between the performance of boys and girls on any of the variables studied, but performance did change with age, and periods of rapid change were identified. Further, when compared on methods used, the children did not achieve the same speed or consistency as the adult participants. CONCLUSION: The development of in-hand manipulation skills of rotation involves improvement in the dimension of speed, method, and consistency. Observation of these skills in a child can add to a therapist's understanding of the child's fine motor abilities. The variability in children's performance needs to be considered in both evaluation and treatment planning.

Environmental support and the development of grasp in infants.

This study examines the acquisition of internal stability as it relates to the development of prehension in normal infants. Thirty-two subjects, 7 to 14 months of age, were observed grasping Cheerios from styrene surfaces that provided different amounts of support to the infants' hands. The subjects were scored on the grasp patterns they used and on their success in securing a Cherrio without dislodging the styrene surface from a platform. Success increased with age, thus demonstrating a developmental progression in the acquisition of upper extremity internal stability. Consistency of grasp also increased with age. Whereas the youngest infants (7 to 8 months old) reverted to immature grasp patterns on the less stable surfaces, the oldest infants (13 to 14 months old) used mature pincer grasp patterns consistently. Infants 10 to 11 months old seemed to be in a transitional stage between the variability of grasp seen in the youngest infants and the consistency achieved by the oldest group.