Enhancing two-dimensional control via single-channel haptic feedback: A multi-dimensional encoding strategy

Haptic feedback elicits sensations of touch to communicate information to
the user. Recent developments in virtual reality and sensory prostheses
have demonstrated the need for systems that can provide more information
than the simple vibrotactor in your phone. A novel multidimensional
encoding approach allows for percepts of signal intensity and flutter
frequency in a single distal location using transcutaneous neural
stimulation. In this study, we aimed to determine if these percepts are
able to convey useful information to participants performing motor control
tasks and if they perform better than a typical intensity-only modulation
approach. Eleven participants performed three types of tasks to assess the
efficacy of multidimensional stimulation. The first set included discrete
matching tasks, where participants had to differentiate between thirteen
combinations of flutter frequency and intensity. In the other two sets,
participants had to differentiate between simultaneous changes in the
percepts. Participants in this study could correctly identify all discrete
percept combinations and follow the changes in the percepts better than
chance. Performance in the discrete task using a multidimensional approach
showed increased information transfer compared to the individual
modulation of intensity or flutter frequency. These results suggest that
multidimensional encoding is a promising approach for increasing
information throughput in sensory feedback systems. Hence, such an
approach might improve upon conventional methods of providing graded
percepts, creating more informative tactile percepts for haptic feedback
through peripheral nerve stimulation.

触觉反馈（Haptic feedback）可唤起触觉感知，用于向用户传递信息。近年来，虚拟现实与感官假肢领域的研究进展显示，现有系统亟需能够传递比手机内置简易振动触觉器更丰富信息的方案。本研究提出的新型多维编码方法，可通过经皮神经刺激（transcutaneous neural stimulation）在单一远端部位实现信号强度与颤动频率的双重感知。本研究旨在探究此类感知能否向执行运动控制任务的受试者传递有效信息，且其表现是否优于仅针对强度进行调制的典型方案。共有11名受试者参与实验，完成三类任务以评估多维刺激的效能。第一类为离散匹配任务，受试者需区分13种颤动频率与强度的组合；其余两类任务中，受试者需识别感知维度的同步变化。本研究中的受试者可准确识别所有离散感知组合，且对感知变化的识别正确率显著高于随机猜测水平。相较于单独调制强度或颤动频率的方案，采用多维编码的离散任务中信息传递量显著提升。上述结果表明，多维编码是提升感官反馈系统信息吞吐量的极具前景的方案。因此，该方法或可改进传统的分级感知传递手段，为基于外周神经刺激的触觉反馈构建信息更为丰富的触觉感知。