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A size-weight illusion was used to examine the role of visual cues in the programming of manipulative forces during the lifting of test objects utilizing the precision grip. Three different boxes of equal weight and unequal size were lifted. These were equipped with an instrumented grip handle to measure the employed grip force, load force (vertical lifting(More)
The capability to store and retrieve weight-related information from a lift to scale the force output during a subsequent lift was examined in 10 healthy adults and 50 children (age 2-10 years), as well as a 22-year-old patient with corpus callosum agenesis. Subjects lifted a test object between the thumb and index finger while the isometric fingertip(More)
Previous studies of grasping and object manipulation in children with cerebral palsy (CP) have suggested a dichotomy in the ability to use anticipatory control (planning) of the fingertip force output, depending on the type of sensory information (tactile or proprioceptive) on which it is based. The present study further explores this issue by testing the(More)
1. While subjects lifted a variety of commonly handled objects of different shapes, weights, and densities, the isometric vertical lifting force opposing the object's weight was recorded from an analog weight scale, which was instrumented with high-stiffness strain gauge transducers. 2. The force output was scaled differently for the various objects from(More)
The present study examines anticipatory control of fingertip forces during grasping based on the center of mass (CM) of a manipulated object. Subjects lifted an object using a precision grip while the fingertip forces and the angle about the vertical axis (roll) were measured. The object's CM could be shifted to the left or right of the object's center(More)
The present study examines the coordination of fingertip forces during object manipulation in both the involved and non-involved hand of 14 children with hemiplegic cerebral palsy (CP) aged between 8 and 14 years. While no impairment could be observed in the non-involved hand, subtle deficits in the sequencing of the grip-lift movement were observed in all(More)
Touch typing movements are typically too brief to use on-line feedback. Yet, previous studies have shown that blocking tactile feedback of the fingertip of typists leads to an increase in typing errors. To determine the contribution of tactile information to rapid fine motor skills, we analyzed kinematics of the right index finger during typing with and(More)
We examined planning and execution of precision grasp in eight right-handed patients with a right pure motor or sensorimotor lacunar syndrome after a subcortical stroke and eight age-matched controls as they grasped and lifted an instrumented object whose weight could be varied without altering its visual appearance. Grip (normal) and load (tangential)(More)
We delineate the methodology for constraint-induced movement therapy (CIMT) modified for children with hemiplegic cerebral palsy (CP) and describe important considerations that need to be made when testing this intervention in children. The resulting intervention evolved from piloting and testing it with 38 children with hemiplegic CP who were between the(More)