Table 2 The parameters of the visually guided reaching task
Parameters | Description |
|---|---|
Upper-limb postural control | |
Posture Speed (m/s) | The mean hand speed for 500 ms before peripheral target illumination, when the hand should be at rest. |
Visual reaction | |
Reaction Time (s) | The time between illumination of the peripheral target and the onset of movement. |
No Reaction Time | The number of trials for which movement to the destination target could not be detected. |
Feed-forward control (initiation of movement) | |
Initial Direction Error (radian) | The angular deviation between (a) a straight line from the hand position at movement onset to the destination target and (b) a vector from the hand position at movement onset to the hand position after the initial phase of movement. |
Initial Distance Ratio | The ratio of (a) the distance the hand traveled during the participants’ initial phase of movement to (b) the distance the hand traveled between movement onset and offset. |
Initial Speed Ratio | The ratio of (a) the maximum hand speed during the participant’s initial phase of movement to (b) the maximum hand speed during the trial. |
Feed-back control (corrective responses) | |
Speed Maxima Count | The number of maxima in hand speed velocity between movement onset and offset. |
Min-Max Speed (m/s) | The differences between local speed peaks and minima. |
Total movement metrics | |
Movement Time (s) | The total time elapsed from movement onset to offset. |
Path Length Ratio | The ratio of (a) the distance travelled by the hand between the movement onset and offset and (b) the straight-line distance between the starting and destination targets. |
Max Speed (m/s) | The maximum hand speed during the trial. |
No Movement End | The number of trials for which a stopping on the destination target was not detected. |