Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle

This article describes a first attempt to generate a standardized and safe selective surface electrostimulation (SES) protocol, including detailed instructions on electrode placement and stimulation parameter choice to obtain a selective stimulation of the denervated zygomaticus muscle (ZYG), withou...

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Main Authors: Dirk Arnold, Jovanna Thielker, Carsten M. Klingner, Wiebke Caren Puls, Wengelawit Misikire, Orlando Guntinas-Lichius, Gerd Fabian Volk
Format: Article
Language:English
Published: MDPI AG 2021-01-01
Series:Diagnostics
Subjects:
Online Access:https://www.mdpi.com/2075-4418/11/2/188
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author Dirk Arnold
Jovanna Thielker
Carsten M. Klingner
Wiebke Caren Puls
Wengelawit Misikire
Orlando Guntinas-Lichius
Gerd Fabian Volk
author_facet Dirk Arnold
Jovanna Thielker
Carsten M. Klingner
Wiebke Caren Puls
Wengelawit Misikire
Orlando Guntinas-Lichius
Gerd Fabian Volk
author_sort Dirk Arnold
collection DOAJ
description This article describes a first attempt to generate a standardized and safe selective surface electrostimulation (SES) protocol, including detailed instructions on electrode placement and stimulation parameter choice to obtain a selective stimulation of the denervated zygomaticus muscle (ZYG), without unwanted simultaneous activation of other ipsilateral or contralateral facial muscles. Methods: Single pulse stimulation with biphasic triangular and rectangular waveforms and pulse widths (PW) of 1000, 500, 250, 100, 50, 25, 15, 10, 5, 2, 1 ms, at increasing amplitudes between 0.1 and 20 mA was performed. Stimulations delivered in trains were assessed at a PW of 50 ms only. The stimulation was considered successful exclusively if it drew the ipsilateral corner of the mouth upwards and outwards, without the simultaneous activation of other ipsilateral or contralateral facial muscles. I/t curves, accommodation quotient, rheobase, and chronaxie were regularly assessed over 1-year follow-up. Results: 5 facial paralysis patients were assessed. Selective ZYG response in absence of discomfort and unselective contraction of other facial muscle was reproducibly obtained for all the assessed patients. The most effective results with single pulses were observed with PW ≥ 50 ms. The required amplitude was remarkably lower (≤5 mA vs. up to 15 mA) in freshly diagnosed (≤3 months) than in long-term facial paralysis patients (>5 years). Triangular was more effective than rectangular waveform, mostly because of the lower discomfort threshold of the latter. Delivery of trains of stimulation showed similar results to the single pulse setting, though lower amplitudes were necessary to achieve the selective ZYG response. Initial reinnervation signs could be detected effectively by needle-electromyography (n-EMG). Conclusion: It is possible to define stimulation parameters able to elicit an effective selective stimulation of a specific facial muscle, in our case, of the ZYG, without causing discomfort to the patient and without causing unwanted unspecific reactions of other ipsilateral and/or contralateral facial muscles. We observed that the SES success is strongly conditioned by the correct electrode placement, which ideally should exclusively interest the area of the target muscles and its immediate proximity.
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spelling doaj.art-d337298e69fb457e8cb79e52fb501a3a2023-12-03T15:03:49ZengMDPI AGDiagnostics2075-44182021-01-0111218810.3390/diagnostics11020188Selective Surface Electrostimulation of the Denervated Zygomaticus MuscleDirk Arnold0Jovanna Thielker1Carsten M. Klingner2Wiebke Caren Puls3Wengelawit Misikire4Orlando Guntinas-Lichius5Gerd Fabian Volk6Facial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyFacial-Nerve-Center Jena, Jena University Hospital, 07740 Jena, GermanyThis article describes a first attempt to generate a standardized and safe selective surface electrostimulation (SES) protocol, including detailed instructions on electrode placement and stimulation parameter choice to obtain a selective stimulation of the denervated zygomaticus muscle (ZYG), without unwanted simultaneous activation of other ipsilateral or contralateral facial muscles. Methods: Single pulse stimulation with biphasic triangular and rectangular waveforms and pulse widths (PW) of 1000, 500, 250, 100, 50, 25, 15, 10, 5, 2, 1 ms, at increasing amplitudes between 0.1 and 20 mA was performed. Stimulations delivered in trains were assessed at a PW of 50 ms only. The stimulation was considered successful exclusively if it drew the ipsilateral corner of the mouth upwards and outwards, without the simultaneous activation of other ipsilateral or contralateral facial muscles. I/t curves, accommodation quotient, rheobase, and chronaxie were regularly assessed over 1-year follow-up. Results: 5 facial paralysis patients were assessed. Selective ZYG response in absence of discomfort and unselective contraction of other facial muscle was reproducibly obtained for all the assessed patients. The most effective results with single pulses were observed with PW ≥ 50 ms. The required amplitude was remarkably lower (≤5 mA vs. up to 15 mA) in freshly diagnosed (≤3 months) than in long-term facial paralysis patients (>5 years). Triangular was more effective than rectangular waveform, mostly because of the lower discomfort threshold of the latter. Delivery of trains of stimulation showed similar results to the single pulse setting, though lower amplitudes were necessary to achieve the selective ZYG response. Initial reinnervation signs could be detected effectively by needle-electromyography (n-EMG). Conclusion: It is possible to define stimulation parameters able to elicit an effective selective stimulation of a specific facial muscle, in our case, of the ZYG, without causing discomfort to the patient and without causing unwanted unspecific reactions of other ipsilateral and/or contralateral facial muscles. We observed that the SES success is strongly conditioned by the correct electrode placement, which ideally should exclusively interest the area of the target muscles and its immediate proximity.https://www.mdpi.com/2075-4418/11/2/188electrostimulationsurface electrodesfacial paralysisfacial palsyzygomaticus musclemuscle atrophy
spellingShingle Dirk Arnold
Jovanna Thielker
Carsten M. Klingner
Wiebke Caren Puls
Wengelawit Misikire
Orlando Guntinas-Lichius
Gerd Fabian Volk
Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
Diagnostics
electrostimulation
surface electrodes
facial paralysis
facial palsy
zygomaticus muscle
muscle atrophy
title Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
title_full Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
title_fullStr Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
title_full_unstemmed Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
title_short Selective Surface Electrostimulation of the Denervated Zygomaticus Muscle
title_sort selective surface electrostimulation of the denervated zygomaticus muscle
topic electrostimulation
surface electrodes
facial paralysis
facial palsy
zygomaticus muscle
muscle atrophy
url https://www.mdpi.com/2075-4418/11/2/188
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