Evaluation of intuitive trunk and non-intuitive leg sEMG control interfaces as command input for a 2-D Fitts's law style task

Stergios Verros; Koen Lucassen; Edsko E G Hekman; Arjen Bergsma; Gijsbertus J Verkerke; Bart F J M Koopman

doi:10.1371/journal.pone.0214645

Evaluation of intuitive trunk and non-intuitive leg sEMG control interfaces as command input for a 2-D Fitts's law style task

PLoS One. 2019 Apr 3;14(4):e0214645. doi: 10.1371/journal.pone.0214645. eCollection 2019.

Authors

Stergios Verros¹, Koen Lucassen¹, Edsko E G Hekman¹, Arjen Bergsma¹, Gijsbertus J Verkerke^{1

2}, Bart F J M Koopman¹

Affiliations

¹ Department Biomechanical Engineering, University of Twente, Enschede, The Netherlands.
² University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.

Abstract

Duchenne muscular dystrophy (DMD) is a muscular condition that leads to muscle loss. Orthotic devices may present a solution for people with DMD to perform activities of daily living (ADL). One such device is the active trunk support but it needs a control interface to identify the user's intention. Myoelectric control interfaces can be used to detect the user's intention and consequently control an active trunk support. Current research on the control of orthotic devices that use surface electromyography (sEMG) signals as control inputs, focuses mainly on muscles that are directly linked to the movement being performed (intuitive control). However in some cases, it is hard to detect a proper sEMG signal (e.g., when there is significant amount of fat), which can result in poor control performance. A way to overcome this problem might be the introduction of other, non-intuitive forms of control. This paper presents an explorative study on the comparison and learning behavior of two different control interfaces, one using sEMG of trunk muscles (intuitive) and one using sEMG of leg muscles that can be potentially used for an active trunk support (non-intuitive). Six healthy subjects undertook a 2-D Fitts's law style task. They were asked to steer a cursor into targets that were radially distributed symmetrically in five directions. The results show that the subjects were generally able to learn to control the tasks using either of the control interfaces and improve their performance over time. Comparison of both control interfaces demonstrated that the subjects were able to learn the leg control interface task faster than the trunk control interface task. Moreover, the performance on the diagonal-targets was significantly lower compared to the one directional-targets for both control interfaces. Overall, the results show that the subjects were able to control a non-intuitive control interface with high performance. Moreover, the results indicate that the non-intuitive control may be a viable solution for controlling an active trunk support.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Activities of Daily Living
Electromyography / methods*
Humans
Learning
Muscle, Skeletal / physiology
Muscular Dystrophy, Duchenne
Orthotic Devices*
Torso

Grants and funding

This work is part of the research programme Perspectief with project number 13526 (Symbionics), which is financed by the Netherlands Organisation for Scientific Research (NWO), Federation to Eradicate Duchenne, Parent Project MD, Duchenne Parent Project, Stichting FSHD, Focal Meditech, BAAT Medical, Intespring and Hankamp. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.