Aoki Tomoko, Francis Peter R, Kinoshita Hiroshi
Graduate School of Human Sciences, Osaka University, 1-2 Yamadaoka, Suita, 565-0871 Osaka, Japan.
Exp Brain Res. 2003 Sep;152(2):270-80. doi: 10.1007/s00221-003-1552-z. Epub 2003 Jul 29.
Using 12 healthy male subjects, the dynamic motor ability of individual fingers was investigated under four different finger tapping conditions. These were: maximum speed tapping with one finger (single-finger tapping), alternate movement of two fingers (double-finger tapping), double-finger tapping in an unsupported condition, and submaximum constant speed tapping with one finger in a passive manner. Key-contact forces for all fingers and the movement velocity of the tapping finger were monitored. With the exception of the unsupported condition, non-tapping fingers were maintained in contact with designated keys during the tapping tasks. It was found that the index finger attained the fastest cadence and greatest movement velocity, followed by the middle, little and ring fingers, respectively. Subjective assessment of rank order of "difficulty" of tapping by the subjects was highly correlated with tapping cadence. Thus dynamic motor function, as indicated by rapid, repetitive movement, differs among the individual fingers. Parallel changes were observed in the key-contact force of the neighboring non-tapping fingers during tapping. The range of the non-tapping finger forces was largest during tapping by the ring finger. A similar trend was found for passive tapping, during which the magnitude of key-contact force was less than one-third of that observed during active tapping. The lower cadence achieved by the ring finger may be attributed more to a lack of independence at the level of voluntary neuromuscular control, than to innate mechanical interaction with the other fingers. Tapping cadence of each finger was lower for the double-finger mode than for the single-finger mode. The magnitude of the observed decrease in cadence during double-finger tapping was, on the other hand, strongly dependent on finger-combination. The decrease was smallest for the index-middle finger-combination, and greatest for the ring-little finger-combination. Compatibilities with other fingers can play an essential role in the dynamic motor function of individual fingers. During the unsupported task, in which interactions were diminished by allowing all fingers to move freely, tapping cadence increased markedly. Therefore, the lower cadences observed in specific finger-combinations may be partly attributed to anatomical and neural interdigit interactions.
使用12名健康男性受试者，在四种不同的手指敲击条件下研究了单个手指的动态运动能力。这四种条件分别是：用一根手指以最大速度敲击（单指敲击）、两根手指交替运动（双指敲击）、在无支撑条件下双指敲击以及用一根手指以次最大恒定速度被动敲击。监测了所有手指的关键接触力以及敲击手指的运动速度。除了无支撑条件外，在敲击任务期间，非敲击手指保持与指定按键接触。结果发现，食指的节奏最快，运动速度最大，其次分别是中指、小指和无名指。受试者对手指敲击“难度”等级顺序的主观评估与敲击节奏高度相关。因此，如快速重复运动所示的动态运动功能在各个手指之间存在差异。在敲击过程中，观察到非敲击手指的关键接触力有平行变化。在无名指敲击期间，非敲击手指力的范围最大。在被动敲击时也发现了类似的趋势，在此期间关键接触力的大小小于主动敲击时观察到的三分之一。无名指实现的较低节奏可能更多地归因于自主神经肌肉控制水平上缺乏独立性，而不是与其他手指的固有机械相互作用。双指模式下每个手指的敲击节奏都低于单指模式。另一方面，双指敲击期间观察到的节奏下降幅度强烈依赖于手指组合。食指 - 中指组合的下降最小，无名指 - 小指组合的下降最大。与其他手指的兼容性在单个手指的动态运动功能中可能起着至关重要的作用。在无支撑任务中，通过允许所有手指自由移动减少了相互作用，敲击节奏明显增加。因此，在特定手指组合中观察到的较低节奏可能部分归因于解剖学和神经指间相互作用。
