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.

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.

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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.

No abstract