Abstract ID 1405
Title
TELMYOS – a feasibility study of a telemetric wheelchair control interface based on the
bilateral recording of myoelectric signals from ear muscles
Abstract
Objective: In individuals with tetraplegia wheelchair mobility is important for participation, but
50% find it hard to operate traditional control interfaces, which interfere with communication or
head orientation.
The aim of this study was to develop a wireless myoelectric auricular control system (ACS)
based on bilateral recording of the electromyogram (EMG) of the posterior auricular muscles
(PAMs), and to investigate its performance for powered wheelchair driving.
Design: The EMG of the PAM was recorded with two subcutaneous fine wire electrodes,
amplified, band pass filtered, digitized and wirelessly sent to proprietary software. Here, EMG
signals of both sides were rectified, integrated, normalized to the maximum contraction level and
converted into steering commands. A higher signal on the left/right caused the wheelchair to turn
left/right, an equal activation of both PAMs resulted in straight driving.
Participants performed four days of computer training (40 min each) and real wheelchair driving
(30 min) on the fifth day. The subjects’ satisfaction was assessed by the NASA Task Load Index
(TLX) and the Assistive Technology Device Predisposition Assessment (ATD PA).
Results: Two subjects with cervical SCI (T1: NLI=C5, AIS A; T2: NLI=C3, AIS C) participated
in the study. T1 classified himself as an “ear wiggler”; T2 as a “non wiggler”. With training all
performance parameters e.g. contraction rate, lateralized activation, and path length in a virtual
obstacle course improved steadily. By day 5, the subjects successfully completed the real
obstacle course with only one collision each. The TLX shows a low to medium workload
(T1=27, T2=57). Temporal demands and frustration did not matter (ATD PA: T2=4.4, T1=3.8).
Conclusion: Activation of PAMs can be learned and used to steer a wheelchair intuitively. The
advantages of the ACS e.g. not interfering with oral communication, robustness and precise
signal generation meet the needs of wheelchair users.
Contact Name
: Ruediger Rupp
Contact Email : [email protected] heidelberg.de
Objective 1. Describe a novel control interface for assistive technology.
Presenters Listed
Rüdiger Rupp, Ph.D1, Leonie Schmalfuß, M.Sc.2, Michele Tuga, M.Sc.3, Andreas Kogut,
B.Sc.1, Manuel Hewitt, M.Sc.2, Ute Eck, M.Sc.1, Ralf Mikut, Ph.D3, Markus Reischl, Ph.D3,
David Liebetanz, M.D.2
1Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany; 2Georg
August University Göttingen, Department of Clinical Neurophysiology, Göttingen, Germany;
3Karlsruhe Institute of Technology, Institute for Applied Computer Science/Automation
Technology, Karlsruhe, Germany
Participants
Ruediger Rupp, Dr. Ing.
Bio
Rüdiger Rupp received the Dipl. Ing. degree in electrical engineering with focus on biomedical
engineering and his Ph.D. degree from the Technical University of Karlsruhe, Germany, in 1994
and 2008, respectively. After working at the Institute for Biomedical Engineering and
Biocybernetics (Prof. G. Vossius) until 1996, he is currently with the Spinal Cord Injury Center
(Head: Prof. N. Weidner) of the University Hospital in Heidelberg, Germany, where he holds the
position as the head of the research group “Experimental Neurorehabilitation”. His main research
interests are in the field of rehabilitation engineering especially for spinal cord injured patients.
This includes neuroprosthetics mainly of the upper extremity, application of functional electrical
stimulation for therapeutic purposes, development and clinical validation of novel methods and
devices for locomotion therapy, gait analysis in incomplete spinal cord injured and realization of
software projects for standardized documentation of rehabilitation outcome. He is author of more
than 170 journal, book and conference abstracts and holds two patents. He has been awarded
several times for his work and is a member of IEEE, IFESS, VDE, DMGP, DGOOC, ISCoS and
ASIA.
Education
Dipl. Ing. from the Technical university of Karlsruhe, Germany in 1994 in the field of Functional
electrical stimulation
Dr. Ing. from the Technical University of Karlsruhe, Germany in 2008 in the field of
neuroprosthetics
Financial Disclosure: This project is funded by the German Federal Ministry of Education and
Research (BMBF) grant no. 13EZ1122. Rüdiger Rupp, Markus Reischl and David Liebetanz are
the PIs and grant recipients of the study. Leonie Schmalfuß, Michele Tuga, Andreas Kogut and
Ute Eck received their salaries by the grant.
Financial Disclosure: Rüdiger Rupp is the head of the Experimental Neurorehabilitation at
Heidelberg University Hospital, Germany and receives a salary.
NonFinancial Disclosure: Rüdiger Rupp serves on the International Standards Committee of the
ASIA, the board of directors of the German Society for Paraplegia and the German foundation
on SCI and receives no compensation as a member.