•Three characteristic factors differentiate fine motor control in patients and controls.
•The three factors are grip force scaling, motor coordination and speed of movement.
•These factors are predictors of 69% of variance for the Jebsen Taylor Hand Function Test.
To determine factors characterizing the differences in fine motor performance between stroke patients and controls. To confirm the relevance of the factors by analyzing their predictive power with regard to the Jebsen Taylor Hand Function Test (JTHFT), a common clinical test of fine motor control.
Twenty-two people with slight paresis in an early chronic phase following stroke and twenty-two healthy controls were examined.. Performance on the JTHFT, Nine-Hole Peg Test and 2-point discrimination was evaluated. To analyze object manipulation skills, grip forces and temporal measures were examined during 1) lifting actions with variations of weight and surface 2) cyclic movements 3) predictive/reactive catching tasks. Three other aspects of force control included 4) visuomotor tracking 5) fast force changes and 6) grip strength.
Based on 9 parameters which significantly distinguished fine motor performance in the two groups, we identified three principal components (factors): grip force scaling, motor coordination and speed of movement. The three factors are shown to predict JTHFT scores via linear regression (R2=.687, p<.001).
We revealed a factor structure behind fine motor impairments following stroke and showed that it explains JTHFT results to a large extend.
Significance: This result can serve as a basis for improving diagnostics and enabling more targeted therapy.