Kinematic analysis of cursor trajectories controlled with a touchpad

To investigate the characteristics of a computer touchpad as a pointing device, 14 participants used their right hand to manipulate the touchpad on a laptop computer. They were required to move a cursor over different distances (7.5 cm, 15 cm) from a home location to targets of different diameters (8 mm, 16 mm), situated to the upper left, middle, or right of a computer screen. A kinematic analysis of movement onsets and cursor trajectories indicated the nature of inefficiencies of the touchpad compared with other devices, primarily excessive submovements. Upper leftward movements were poorer, which can be explained by asymmetries in the finger-wrist system. This result implies that screen accessibility can vary as a function of users' interaction with cursor controllers and that the default placements of key icons might need to vary as a consequence.