A cross-modal feedback scheme for control of prosthetic grasp strength

Abstract

Introduction Given the lack of haptic feedback inherent in prosthetic devices, a natural and adaptable feedback scheme must be implemented. While multimodal feedback has proven successful in aiding dexterous performance, it can be mentally tasking on the individual. Conversely, cross-modal schemes relying on sensory substitution have proven to be equally effective in aiding task performance without cognitively burdening the user to the same degree. Objectives This experiment investigated the effectiveness of the cross-modal feedback scheme through using audio feedback to represent prosthetic grasping strength during dynamic control of a prosthetic hand. Methods A total of five individuals participated in two sets of experiments (four subjects in the first, one subject in the second). Participants were asked to control the grasping strength exerted by a prosthetic hand while using real-time audio feedback in order to reach up to three different levels of force within a trial set. Results The cross-modal feedback scheme successfully provided users with the robust ability to modulate grasping strength in real-time using only audio feedback. Conclusion Audio feedback effectively conveys haptic information to the user of a prosthetic hand. Retention of the training knowledge is evident and can be generalized to perform new (i.e. untrained) tasks.