Analysis of Reach-to-Grasp by School-Aged Children with Down Syndrome Elucidates Limitations in Upper Extremity Motor Control.
OBJECTIVE
To identify limitations in preparatory planning (PP) and movement execution that constrain performance of reach-to-grasp (RTG) movements in school-aged children with Down syndrome (DS) and examine the effect of chronological age (CA) on performance.


METHODS
Nine children with DS ages 6 to 12 years and nine with typical development (TD) participated in this pilot descriptive study. Three-dimensional kinematic analysis was applied to RTG movements performed in the context of two functional tasks.


RESULTS
PP variables focused on the coordination of reach and grasp. Compared to the group with TD, the group with DS demonstrated significant limitations in anticipatory slowing down of hand transport and orientation of the hand in preparation for object contact. There was also relatively late onset of preparatory grip formation in the group with DS. In regard to movement execution, reach trajectories of the group with DS showed significantly greater deviation from the straight path. Correlations of study variables with CA were low and insignificant in both groups.


CONCLUSIONS
Motor control mechanisms that mediate both PP and execution of the fundamental RTG movement are potential factors limiting upper extremity activity in school-aged children with DS. They should be addressed in future intervention-based research.
a Department of Physical Medicine and Rehabilitation, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.|b Center for Gait and Movement Analysis , Children's Hospital Colorado , Aurora , Colorado , USA.
Joanne
J
Valvano
c Mayo Clinic , Phoenix , Arizona , USA.
Sara
S
Hogy
d Medtronic Neurosurgery , Louisville , Colorado , USA.
Kate
K
Worster
e School of Medicine , Creighton University , Omaha , Nebraska , USA.
Julie
J
Ma
b Center for Gait and Movement Analysis , Children's Hospital Colorado , Aurora , Colorado , USA.
Nancy
N
Denniston
f Sie Center for Down Syndrome , Aurora , Colorado , USA.
Patricia
P
Winders
a Department of Physical Medicine and Rehabilitation, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.|g Department of Pediatrics, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.
Mary Jane
MJ
Rapport
g Department of Pediatrics, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.
Zhaoxing
Z
Pan
a Department of Physical Medicine and Rehabilitation, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.|b Center for Gait and Movement Analysis , Children's Hospital Colorado , Aurora , Colorado , USA.|h Department of Orthopedics, School of Medicine , University of Colorado Denver , Aurora , Colorado , USA.
James J
JJ
Carollo
D001696:Biomechanical Phenomena; D002648:Child; D004314:Down Syndrome / Q000503:physiopathology*; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D034941:Upper Extremity / Q000503:physiopathology*
Down syndrome; fine motor; motor control; reach-to-grasp; upper extremity