Stimulation of paralysed quadriceps muscles with sequentially and spatially distributed electrodes during dynamic knee extension

Marco Laubacher; Efe A Aksoez; Anne K Brust; Michael Baumberger; Robert Riener; Stuart Binder-Macleod; Kenneth J Hunt

doi:10.1186/s12984-018-0471-y

Stimulation of paralysed quadriceps muscles with sequentially and spatially distributed electrodes during dynamic knee extension

J Neuroeng Rehabil. 2019 Jan 7;16(1):5. doi: 10.1186/s12984-018-0471-y.

Authors

Marco Laubacher¹, Efe A Aksoez², Anne K Brust², Michael Baumberger^{3

4}, Robert Riener^{3

4}, Stuart Binder-Macleod⁵, Kenneth J Hunt⁵

Affiliations

¹ Department of Physical Therapy, University of Delaware, Newark, United States of America. marco.laubacher@bfh.ch.
² Department of Physical Therapy, University of Delaware, Newark, United States of America.
³ Institute for Rehabilitation and Performance Technology, Division of Mechanical Engineering, Department of Engineering and Information Technology, Bern University of Applied Sciences, Pestalozzistrasse 20, Burgdorf, 3400, Switzerland.
⁴ Sensory Motor Systems Lab, Department of Health Sciences and Technology, ETH Zurich, Zurich, 8000, Switzerland.
⁵ Swiss Paraplegic Centre, Nottwil, 6207, Switzerland.

Abstract

Background: During functional electrical stimulation (FES) tasks with able-bodied (AB) participants, spatially distributed sequential stimulation (SDSS) has demonstrated substantial improvements in power output and fatigue properties compared to conventional single electrode stimulation (SES). The aim of this study was to compare the properties of SDSS and SES in participants with spinal cord injury (SCI) in a dynamic isokinetic knee extension task simulating knee movement during recumbent cycling.

Method: Using a case-series design, m. vastus lateralis and medialis of four participants with motor and sensory complete SCI (AIS A) were stimulated for 6 min on both legs with both electrode setups. With SES, target muscles were stimulated by a pair of electrodes. In SDSS, the distal electrodes were replaced by four small electrodes giving the same overall stimulation frequency and having the same total surface area. Torque was measured during knee extension by a dynamometer at an angular velocity of 110 deg/s. Mean power of the left and right sides (P_meanL,R) was calculated from all stimulated extensions for initial, final and all extensions. Fatigue is presented as an index value with respect to initial power from 1 to 0, whereby 1 means no fatigue.

Results: SDSS showed higher P_meanL,R values for all four participants for all extensions (increases of 132% in participant P1, 100% in P2, 36% in P3 and 18% in P4 compared to SES) and for the initial phase (increases of 84%, 59%, 66%, and 16%, respectively). Fatigue resistance was better with SDSS for P1, P2 and P4 but worse for P3 (0.47 vs 0.35, 0.63 vs 0.49, 0.90 vs 0.82 and 0.59 vs 0.77, respectively).

Conclusion: Consistently higher P_meanL,R was observed for all four participants for initial and overall contractions using SDSS. This supports findings from previous studies with AB participants. Fatigue properties were better in three of the four participants. The lower fatigue resistance with SDSS in one participant may be explained by a very low muscle activation level in this case. Further investigation in a larger cohort is warranted.

Keywords: Fatigue; Functional electrical stimulation; Knee dynamometer; Power output; Rehabilitation; Spatially distributed sequential stimulation; Spinal cord injury.

Publication types

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

MeSH terms

Adult
Electric Stimulation Therapy / methods*
Electrodes
Female
Humans
Knee Joint / physiopathology
Male
Muscle Fatigue / physiology*
Paralysis / physiopathology*
Quadriceps Muscle / physiopathology
Spinal Cord Injuries / physiopathology*
Young Adult

Grants and funding

15128/1/Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung/International