Affiliations: [a] Georg-August-University Göttingen, Department of Clinical Neurophysiology, Göttingen, Germany
| [b] Heidelberg University Hospital, Spinal Cord Injury Center, Heidelberg, Germany | [c] Karlsruhe Institute of Technology, Institute for Applied Computer Science/Automation Technology, Karlsruhe, Germany | [d] Karlsruhe Institute of Technology, Institute for Applied Computer Science, Karlsruhe, Germany
Correspondence:
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Corresponding author: D. Liebetanz, University Medical Center, Robert Koch Str. 40, 37075 Göttingen, Germany. Tel.: +49 551 39 6650; E-mail: David.Liebetanz@medizin.uni-goettingen.de.
Correspondence:
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Corresponding author: M. Reischl, Karlsruhe Institute of Technology, Institute for Applied Computer Science, Hermann-von-Helmholtz-Platz 1, 76344 Karlsruhe, Germany. Tel.: +49 721 608 25749; E-mail: Markus.Reischl@kit.edu.
Note: [1] These authors contributed equally to this paper.
Abstract: Purpose:Providing mobility solutions for individuals with tetraplegia remains challenging. Existing control devices have shortcomings such as varying or poor signal quality or interference with communication. To overcome these limitations, we present a novel myoelectric auricular control system (ACS) based on bilateral activation of the posterior auricular muscles (PAMs). Methods:Ten able-bodied subjects and two individuals with tetraplegia practiced PAM activation over 4 days using visual feedback and software-based training for 1 h/day. Initially, half of these subjects were not able to voluntarily activate their PAMs. This ability was tested with regard to 8 parameters such as contraction rate, lateralized activation, wheelchair speed and path length in a virtual obstacle course. In session 5, all subjects steered an electric wheelchair with the ACS. Results:Performance of all subjects in controlling their PAMs improved steadily over the training period. By day 5, all subjects successfully generated basic steering commands using the ACS in a powered wheelchair, and subjects with tetraplegia completed a complex real-world obstacle course. This study demonstrates that the ability to activate PAM on both sides together or unilaterally can be learned and used intuitively to steer a wheelchair. Conclusions:With the ACS we can exploit the untapped potential of the PAMs by assigning them a new, complex function. The inherent advantages of the ACS, such as not interfering with oral communication, robustness, stability over time and proportional and continuous signal generation, meet the specific needs of wheelchair users and render it a realistic alternative to currently available assistive technologies.
