Table 1 Summary of the performance metrics for the goal-directed tasks

Continuous Tracking

Percentage Time in Target (PTT)

The percentage of the time the human subject staying within the target window.

Accuracy and Steadiness

Root Mean Square Error (RMSE)

The squared root of the mean-squared distance from the subject position to the target position.

Accuracy

Deviation

The mean of the perpendicular distance from the subject position to the target line within the movement time.

Path Deviation

Speed_Mean (SM)

The mean of the subject speed during the continuous tracking task

Speed Consistency

Speed_StdDev (SS)

The standard deviation of the subject speed during the continuous tracking task

Speed Consistency

Discrete Tracking

(Target Acquisition)

Reaction Time

The time from the movement of the target to the first significant movement made by the subject.

Reaction Quickness

Movement Time

The time window from the end of the reaction time to the time after which the user has stably reached the target.

Movement Quickness

Deviation

The mean of the perpendicular distance from the subject position to the target path line.

Path Deviation

Movement Speed

The mean of subject speed.

Movement Quickness

Peak Speed Number

The number of local maximum speed within the movement time window.

Smoothness

Dwelling Percentage Time in Target

The percentage of the time that the subject stayed within the target window during the Dwelling Time.

Stability

Success Percentage

The percentage of the targets that have been successfully reached by the subject.

Overall Reaching Capability

System Identification

Error_Mean

The mean of the displacement outside of the holding area in both x and y direction

Strength (under "hold" instruction)

Error_StdDev.

The standard deviation of the displacement outside of the holding area in both x and y direction