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Development of hand function and precision grip control in individuals with cerebral palsy: a 13-year follow-up study
Ann-Christin Eliasson1, Hans Forssberg, Ya-Ching Hung
1Department of Woman and Child Health, Karolinska Institute, Stockholm, Sweden.
Insights
Children with cerebral palsy show improved hand function over time. This study tracked manual dexterity and fingertip force control in participants over 13 years, revealing significant developmental gains.
Area of Science:
- Developmental neuroscience
- Motor control in cerebral palsy
- Hand function rehabilitation
Background:
- Significant hand function differences exist in children with cerebral palsy (CP) compared to typically developing peers by age 6-10.
- Limited understanding of the developmental trajectory of hand function in individuals with CP beyond early childhood.
Purpose of the Study:
- To investigate the developmental changes in manual dexterity and fingertip force control during a precision grasping task in individuals with CP.
- To analyze the relationship between changes in motor task timing, force application, and intertrial variability over time.
Main Methods:
- Longitudinal study tracking 10 individuals with CP (initially aged 6-8, re-evaluated at 19-21 years).
- Assessment of manual dexterity using the Jebsen-Taylor test of hand function.
- Quantitative analysis of fingertip force application during a precision grip-lift task, including force trajectory shape and intertrial variability using generalized Procrustes analysis.
Main Results:
- Significant improvements observed in Jebsen-Taylor test times (45% decrease) and grip-lift task completion (22% decrease).
- Reduced grip-force/load-force path ratios indicate more efficient force application (from 1.7 to 1.35).
- Generalized Procrustes analysis revealed changes in force trajectory shape and decreased intertrial variability.
Conclusions:
- Hand function, specifically grasping efficiency, demonstrates significant development over a 13-year period in individuals with CP.
- These findings suggest that improvements in hand function for individuals with CP can continue over a longer timeframe than typically assumed.
Objective:
Although children with cerebral palsy display large developmental differences in hand function from that of typically developing children by the age of 6 to 10 years, little is known about the developmental processes underlying hand function during subsequent development. In this study we investigated the development of manual dexterity in a timed motor task, the timing and amplitude of fingertip-force application during a precision grasping task, and the relationship between changes in these measures. We applied highly quantitative analytical approaches to determine if the fingertip-force application pattern and trial-to-trial variation of fingertip-force application change during development.
Methods:
Twelve subjects with cerebral palsy (aged 6-8 years) participated in the first data-collection session conducted between 1989 and 1990. Ten of these subjects (5 with hemiplegia and 5 with diplegia, aged 19-21 years) returned between 2002 and 2003. Manual dexterity was measured by using timed tasks of the Jebsen-Taylor test of hand function. Subjects also lifted an object instrumented with force transducers while we measured the temporal coordination of fingertip coordination and the path ratio between the grip and vertical load-force trajectory (straightness). We used generalized procrustes analysis to determine if there were changes in shape of the force trajectory and intertrial variability.
Results:
The Jebsen-Taylor test times decreased 45% from the first to the second data session. The overall time to complete the grip-lift task decreased 22%, mainly because of a faster transition from grasp to lift. The grip-force/load-force path ratios decreased from 1.7 to 1.35 (1 = straight line). Generalized procrustes analysis indicated a change in the shape and a decrease in variability in shape of the force-ratio path.
Conclusions:
Our results demonstrate that the efficiency in grasping had developed during a 13-year period for this small group of participants with cerebral palsy, which suggests that improvement in hand function occurs over a longer time frame than commonly would be expected.
