Rao R S, Seliktar R, Rahman T
Pulmonary Function Laboratory, Temple University Hospital, Philadelphia, PA 19140, USA.
IEEE Trans Rehabil Eng. 2000 Mar;8(1):118-25. doi: 10.1109/86.830956.
Individuals with cerebral palsy (CP) with upper limb disability have difficulty operating standard computer input devices such as, a mouse and a keyboard. The present study evaluated the performance of unimpaired individuals and those with CP in the use of a zero-order spring-centered position joystick and a zero-order isometric joystick when interacting with the computer. We hypothesize that the isometric device due to its stiff resistance would provide better control on cursor movement than the position joystick. The subjects acquired differently sized targets at different distances by positioning a cursor on the target. Performance with the position joystick was superior to that of the isometric joystick. The time to acquire the target was directly proportional to the cursor-target distance A, and indirectly proportional to the target size W. Subjects chose to move more slowly toward the smaller and closer targets and they increased speed for larger and more distant targets. The phase-plane diagram that plots values of the velocity profile of the cursor over its displacement revealed the presence of one large amplitude movement that accounts for the peak velocity of the cursor, and several submovements. Fitts' index of difficulty, log(e)(2W/A) was found to be a good predictor of the movement time in a cursor positioning task for both, unimpaired individuals and those with CP.
患有上肢残疾的脑瘫（CP）患者在操作标准计算机输入设备（如鼠标和键盘）时存在困难。本研究评估了健全个体和患有CP的个体在使用零阶弹簧中心位置操纵杆和零阶等距操纵杆与计算机交互时的表现。我们假设，由于其刚性阻力，等距设备在光标移动控制方面将优于位置操纵杆。受试者通过将光标定位在目标上来获取不同距离处不同大小的目标。位置操纵杆的表现优于等距操纵杆。获取目标的时间与光标到目标的距离A成正比，与目标大小W成反比。受试者选择朝着更小、更近的目标移动得更慢，而对于更大、更远的目标则加快速度。绘制光标速度分布值与其位移关系的相平面图显示，存在一个占光标峰值速度的大幅度运动以及几个子运动。发现Fitts难度指数log(e)(2W/A)是健全个体和患有CP的个体在光标定位任务中运动时间的良好预测指标。
