Adaptation to random and systematic errors: Comparison of amputee and non-amputee control interfaces with varying levels of process noise

The objective of this study was to understand how people adapt to errors when using a myoelectric control interface. We compared adaptation across 1) non-amputee subjects using joint angle, joint torque, and myoelectric control interfaces, and 2) amputee subjects using myoelectric control interfaces with residual and intact limbs (five total control interface conditions). We measured trial-by-trial adaptation to self-generated errors and random perturbations during a virtual, single degree-of-freedom task with two levels of feedback uncertainty, and evaluated adaptation by fitting a hierarchical Kalman filter model. We have two main results. First, adaptation to random perturbations was similar across all control interfaces, whereas adaptation to self-generated errors differed. These patterns matched predictions of our model, which was fit to each control interface by changing the process noise parameter that represented system variability. Second, in amputee subjects, we found similar ...本研究旨在探究使用者在操作肌电控制界面（myoelectric control interface）时如何适应操作失误。我们对比了两类受试者的适应表现：1）非截肢受试者，分别采用关节角度、关节力矩及肌电控制界面开展操作；2）截肢受试者，分别借助残肢与健肢使用肌电控制界面，共计5种控制界面条件。我们在一项包含两种反馈不确定性水平的虚拟单自由度任务中，逐试次测量了受试者针对自主产生的失误与随机扰动的适应情况，并通过分层卡尔曼滤波（hierarchical Kalman filter）模型拟合来评估适应效果。本研究主要得到两项核心结论。其一，所有控制界面下受试者对随机扰动的适应表现相近，而针对自主失误的适应则存在显著差异；该规律与我们的模型预测相符——我们通过调整代表系统变异性的过程噪声参数，为每种控制界面完成了模型拟合。其二，在截肢受试者中，我们发现相似的……