Purpose/aim of the study: We aimed to establish psychophysical principles for non-invasive vibrotactile feedback signalling discrete transition events (e.g., extension to flexion) during use of prostheses, especially for the upper limbs.

Materials and methods: Two vibrotactile actuators were used on both upper arms of 10 able-bodied human participants. Absolute thresholds, psychometric functions, and magnitude estimates were measured to equalize the sensation magnitudes for the tested vibrotactile frequencies and skin sites. Then, same-different and pattern recognition tasks were run to evaluate, respectfully, the discrimination and closed-set identification of stimuli with varying parameters (2 frequencies, 2 magnitudes, 2 sites). Finally, parameters of the left/right stimuli were mapped to hypothetical prosthesis events representing object/force and movement type. The stimuli were applied sequentially in accordance with the discrete event-driven feedback paradigm.

Results: Reliable psychophysical models could be established for individual participants as verified by repetitive threshold measurements and relative adjustment of stimulus levels based on sensation magnitudes. Discrimination accuracy was higher for magnitude versus frequency comparisons; and magnitude discrimination accuracy was correlated with magnitude estimate differences. Pattern recognition recall/precision rates decreased from ∼0.7 to ∼0.5 for sequential delivery of two stimulus patterns to one arm versus to two arms. Using the patterns as two and three consecutive prosthesis events yielded statistically similar performance rates not correlated with magnitude estimate differences.

Conclusions: By careful calibration of stimuli based on psychophysical principles, discrete event-driven vibrotactile feedback can be used to signal manipulated object and movement information with moderate identification rates as shown by confusion matrices.

研究的目的/目的：我们旨在建立非侵入性振动触觉反馈信号离散转换事件（例如，伸展至屈曲）在使用假肢期间的心理物理学原理，尤其是对于上肢。

材料和方法：在 10 名身体健全的人类参与者的双上臂上使用了两个振动触觉致动器。测量绝对阈值、心理测量函数和幅度估计以平衡测试振动触觉频率和皮肤部位的感觉幅度。然后，运行相同不同和模式识别任务，以分别评估具有不同参数（2 个频率、2 个量级、2 个站点）的刺激的辨别和闭集识别。最后，左/右刺激的参数被映射到代表物体/力和运动类型的假设假肢事件。根据离散事件驱动的反馈范式依次应用刺激。

结果：通过重复阈值测量和基于感觉幅度的刺激水平的相对调整，可以为个体参与者建立可靠的心理物理模型。幅度与频率比较的区分准确度更高；并且幅度区分精度与幅度估计差异相关。模式识别召回率/准确率从~0.7 降低到~0.5，将两种刺激模式顺序传递到一只手臂和两只手臂。使用模式作为两个和三个连续的假体事件产生统计上相似的性能率，与幅度估计差异无关。

结论：通过基于心理物理学原理对刺激进行仔细校准，离散事件驱动的振动触觉反馈可用于以中等识别率发出信号操纵对象和运动信息，如混淆矩阵所示。