In previous studies, we have found that children with hemiplegic cerebral palsy (CP) lack anticipatory scaling of fingertip forces (impairment in planning) during lifts of novel objects with the involved hand, unless given extended practice. However, it is not known whether they use such anticipatory control during manipulation of objects they have previously handled. The purpose of this study was to determine whether they have anticipatory control of familiar objects of different weights and sizes when grasping with their involved hand.

Design: A descriptive study examining fingertip forces.

Measurements and Main Results:

Participants grasped and lifted seven familiar objects (determined by an interview and a Likert scale) five times each while the vertical lifting force was measured. Four of these objects were chosen to determine levels of anticipatory control in children with hemiplegic CP for various weights: a chalkboard eraser (25g), videotape (210g), soda can (390g), and a lemonade bottle (720g) were used. Three other objects were selected to determine whether participants could use size information to estimate weight: a small (36.9ml, 50g), medium (118ml, 145g), and large (225ml, 275g) bottle of glue. Each object was lifted off of a plastic plate covering a force transducer on a table (resembling a scale) with the involved (CP) or non-dominant (control) hand. We found that both groups of children demonstrated higher lift-force rates of increase for heavier (p<0.05) and larger (p<0.05) objects on the first lift, indicating anticipatory control. The force rates did not change across the five lifts, indicating that they had stable representations of these objects.

These findings suggest that children with hemiplegic CP have strong internal representations for selecting familiar objects, which they can use for anticipatory control during manipulation. Together with our earlier work, the results from this study suggest that children with CP have better coordination of fingertip forces for familiar than unfamiliar objects, which may have important implications for functional prehension.

Acknowledgements: This project was supported by The DeanÕs Grant for Student Research from Teachers College, Columbia University, New York, USA.

Childhood Disability Update 2005 - Conference Abstracts.Pediatric Oncall [serial online] 2006 [cited 15 January 2006(Supplement 1)];3. Available from:
http://www.pediatriconcall.com/fordoctor/Conference_abstracts/
hemiplegic_cerebral_palsy.asp