Audible Feedback Improves Internal Model Strength and Performance of Myoelectric Prosthesis Control

Abstract

Myoelectric prosthetic devices are commonly used to help upper limb amputees perform activities of daily living, however amputees still lack the sensory feedback required to facilitate reliable and precise control. Augmented feedback may play an important role in affecting both short-term performance, through real-time regulation, and long-term performance, through the development of stronger internal models. In this work, we investigate the potential tradeoff between controllers that enable better short-term performance and those that provide sufficient feedback to develop a strong internal model. We hypothesize that augmented feedback may be used to mitigate this tradeoff, ultimately improving both short and long-term control. We used psychometric measures to assess the internal model developed while using a filtered myoelectric controller with augmented audio feedback, imitating classification-based control but with augmented regression-based feedback. In addition, we evaluated the short-term performance using a multi degree-of-freedom constrained-time target acquisition task. Results obtained from 24 able-bodied subjects show that an augmented feedback control strategy using audio cues enables the development of a stronger internal model than the filtered control with filtered feedback, and significantly better path efficiency than both raw and filtered control strategies. These results suggest that the use of augmented feedback control strategies may improve both short-term and long-term performance.

Myoelectric control with abstract decoders

“…We anticipate that real use of these methods may utilise the economic feedback protocol hypothesized by Dosen et al to gradually reduce overall reliance on feedback whilst also providing intermittent information to ensure internal models remain stable [64]. It may be the case that other forms of feedback, such as artificial proprioception [23], vibro-tactile stimulation [65], or audio augmented feedback [66] will be more appropriate to provide information about the current state, in order to facilitate the development of the internal model.…”

Joint Speed Discrimination and Augmentation For Prosthesis Feedback

“…Sensory feedback remains a research priority for prosthesis users 6 . Several feedback methods have been proposed over the past decades, including vibrotactile [7][8][9][10][11] , electrotactile 8 , skin stretch 7 , audio [12][13][14] and visual 15 modalities 16,17 . More complex feedback modalities like peripheral nerve stimulation 18 and vibration-induced illusory kinesthesia 19 have also been introduced to great effect.…”

“…More complex feedback modalities like peripheral nerve stimulation 18 and vibration-induced illusory kinesthesia 19 have also been introduced to great effect. Sensory feedback typically falls into two categories: tactile feedback of grasping force 9,11,18 , and proprioceptive feedback of limb movement 7,8,10,[12][13][14][15]19 . Vision is capable of estimating grasping force similarly to tactile feedback 20 , though several grasping force feedback studies have still shown significant benefit to prosthesis control with vision present.…”