Prehension in young children with Down syndrome.
Prehension was examined in 3-year old children with Down syndrome (DS, n = 3) and in typically-developing children matched in chronological age (3-year olds; n = 3) or mental age and motor experience (2-year olds; n = 3). The task required reaching to grasp dowels. Video-based movement analysis yielded temporal and kinematic measures. Children with DS were hypothesized to have deficits in feedback-dependent components of prehension (anticipatory grip-closure and deceleration of reach), whereas feedforward components (reach's acceleration phase; grasp's preshaping) were assumed to be unimpaired [Latash, 1993, Control of human movement, pp. 283-292; Latash, 1994, What is clumsiness? In: Motor Control and Down Syndrome II Proceedings of the second international conference, pp. 68-71]. The findings supported these hypotheses. In comparison to control groups, children with DS had significantly: (a) less time in deceleration of reaching, (b) fewer anticipatory grip-closures, and (c) longer movement times for dowel-lift. Young children with DS appeared to use dowel-contact to decelerate the limb and initiate grip-closure. In contrast, reach-acceleration time and grasp-preshaping did not differ across groups. These findings suggest that children with DS display qualitative differences in motor capabilities rather than simply a delayed rate of typical developmental progression.
Kearney
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Department of Biobehavioral Studies, Teachers College, Columbia University, Box 199, 525 West 120 Street, New York City, NY 10027, USA. kmk26@columbia.edu
Gentile
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AM
D002675:Child, Preschool; D002658:Developmental Disabilities / Q000150:complications; D004314:Down Syndrome / Q000150:complications*; D005246:Feedback; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D019957:Motor Skills Disorders / Q000150:complications*; D011596:Psychomotor Disorders / Q000150:complications; D014743:Videotape Recording