A cross-sectional study examining computer task completion by adolescents with cerebral palsy across the Manual Ability Classification System levels

Abstract

Aim: The aim of this study was to analyze the cursor trajectories of adolescents with cerebral palsy (CP) when using a mouse for point-and-click computer tasks. By identifying some of the factors limiting cursor movement and gaining a better understanding of human movement, it will be possible to design more accessible computer interfaces. Method: This study evaluated cursor trajectories of 29 individuals with bilateral CP who had different levels of upper limb function as measured by the Manual Ability Classification System, and compared the results with those of 12 adolescents with typical development. Results: Among adolescents with typical development, movement time increases linearly as the index of difficulty increases (Fitts' law); however, this linearity was not apparent in adolescents with bilateral CP. Interpretation: Interfaces for members of the population are designed around Fitts' law, with low precision requirements at indices of difficulty lower than 4. We found that interactive displays for adolescents with CP should be limited to an index of difficulty of 2. What this paper adds: Movement time did not increase linearly with the index of difficulty among adolescents with CP. Movement time was higher among individuals in Manual Ability Classification System levels II and III than in adolescents with typical development, regardless of the index of difficulty. Size and placement of icons on a screen should be limited to an index of difficulty of 2.