Bravo P E, LeGare M, Cook A M, Hussey S
Department of Psychology, California State University, Sacramento 95819-6007.
Percept Mot Skills. 1993 Dec;77(3 Pt 2):1107-17. doi: 10.2466/pms.1993.77.3f.1107.
Fitts' Law was applied to the evaluation of discrete aimed arm movements in one dimension performed by 6 adults with cerebral palsy and 6 adults with normal movement. Targets (1.27, 3.81, 6.35, 8.89 cm in width) placed at distances of 20.32, 30.48, 40.64, and 50.80 cm provided Indices of Difficulty of 2.19 to 6.32 bits. A video game was used for the signal to move. The t tests for corrected means showed that the cerebral palsied group had greater reaction and movement times than than the normal group. Linear regression analyses for pooled data and for the individual cerebral palsied subjects showed (a) no relationship between reaction time and Index of Difficulty for either group and (b) a negative, linear relationship between reaction time and Index of Difficulty for 1 cerebral palsied subject. Movement time was linearly and positively related to the Index of Difficulty for the normal group but not for the cerebral palsied group. Two cerebral palsied subjects had movement times which conformed to Fitts' Law. While the exceptions to Fitts' Law may be due to the limited range of movement and spasticity caused by severe cerebral palsy, there are indications that two of the cerebral palsied subjects were performing ballistic rather than visually guided aimed movements. Fitts' Law may still apply when the distances and target positions are individualized to conform to subjects' specific limitations and when the signal to move is auditory rather than visual.
菲茨定律被应用于评估6名患有脑瘫的成年人和6名运动正常的成年人在一维空间中进行的离散目标手臂运动。放置在20.32、30.48、40.64和50.80厘米距离处的目标（宽度分别为1.27、3.81、6.35、8.89厘米）提供了2.19至6.32比特的难度指数。使用一款电子游戏作为移动信号。对校正均值进行的t检验表明，脑瘫组的反应时间和运动时间比正常组更长。对汇总数据以及个体脑瘫受试者进行的线性回归分析表明：（a）两组的反应时间与难度指数之间均无关系；（b）1名脑瘫受试者的反应时间与难度指数之间呈负线性关系。正常组的运动时间与难度指数呈线性正相关，而脑瘫组则不然。两名脑瘫受试者的运动时间符合菲茨定律。虽然菲茨定律的例外情况可能是由于严重脑瘫导致的运动范围有限和痉挛，但有迹象表明，两名脑瘫受试者进行的是弹道式运动而非视觉引导的目标运动。当距离和目标位置根据受试者的具体限制进行个体化设置，并且移动信号为听觉而非视觉信号时，菲茨定律可能仍然适用。
