A Dynamic Speed vs. Accuracy Trade-Off (DSAT) Paradigm for Measuring and Training Grip Force Control for Stroke Population

A fundamental principle of human motor behavior states that the accuracy of targeted movements relates reciprocally to their speed. This is quantified by Fitts’ Law, wherein movement time (MT) and index of difficulty (ID), the log₂ ratio of target distance (A) to target height (H) has logarithmic linear relationship; MT = a+b·log₂(2A/H) = a+b·ID. The slope, b (seconds/bits), measures targeting performance as the time spent at each difficulty level, expressed as bits of information to be processed by the neuromotor system [1, 2]. Fitts’ paradigm is a common measure of the kinematic performance of the upper limb, but has not been applied to its dynamic performance. Herein, we developed a dynamic speed-accuracy trade-off (DSAT) test of grip force modulation, which can be used both for assessment and training.