The role of augmentative visual training in auditory human-machine-interface performance

The purpose of this study was to evaluate the effect of augmentative visual feedback training on performance using auditory feedback alone for human-machine interface (HMI) control. Sixteen healthy participants used bilateral facial surface electromyography to achieve two-dimensional control to reach vowel targets. Eight participants trained with combined visual and auditory feedback, while eight participants trained with real-time auditory feedback only. Each subject participated in four sessions over three days; three sessions with their designated feedback modality (auditory only or auditory with supplementary visual) and a fourth session on the third day using novel vowel targets to test generalization of auditory-motor learning. Analyses of variance performed on the percentage of total targets reached demonstrated a main effect of group and the interaction of group and session. Individuals provided with augmentative visual feedback during training outperformed individuals using auditory feedback alone in initial training sessions. However, training with augmentative visual feedback had no effect on individuals´ training and generalization performance using auditory feedback alone after three days of training.