Enhancing Two-Dimensional Control via Single-Channel Haptic Feedback: A Multi-dimensional Encoding Strategy

Recently a multidimensional encoding approach to direct stimulation of a single site in the median nerve showed that an intensity and flutter frequency could be perceived and graded. It is unclear whether these two dimensions are able to convey useful information to participants performing control tasks or whether they improve on typical intensity only modulation approach. Eleven participants performed experiments to assess the efficacy of multidimensional stimulation. In a set of discrete matching tasks, participants were able to correctly identify all thirteen discrete stimulation points better than chance. In a modified center-out task, and three separate extremes-in tasks, all seventeen changes in the stimulation parameters could be detected better than chance. Performance of the discrete task using a multidimensional approach showed increased information transfer compared to the individual modulation of intensity or flutter frequency. The results suggest that multidimensional encoding is a promising approach for increasing information throughput in sensory feedback systems. By investigating a multimodal encoding approach, this study offers valuable insights into haptic feedback through peripheral nerve stimulation. This haptic feedback might offer pronounced benefits for virtual reality applications and individuals with upper limb amputations opening avenues for an enhanced sensory feedback experience.