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Stålberg, Erik
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Publications (10 of 77) Show all publications
Tankisi, H., Burke, D., Cui, L., de Carvalho, M., Kuwabara, S., Nandedkar, S. D., . . . Fuglsang-Frederiksen, A. (2020). Standards of instrumentation of EMG. Clinical Neurophysiology, 131(1), 243-258
Open this publication in new window or tab >>Standards of instrumentation of EMG
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2020 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 131, no 1, p. 243-258Article, review/survey (Refereed) Published
Abstract [en]

Standardization of Electromyography (EMG) instrumentation is of particular importance to ensure high quality recordings. This consensus report on "Standards of Instrumentation of EMG" is an update and extension of the earlier IFCN Guidelines published in 1999. First, a panel of experts in different fields from different geographical distributions was invited to submit a section on their particular interest and expertise. Then, the merged document was circulated for comments and edits until a consensus emerged. The first sections in this document cover technical aspects such as instrumentation, EMG hardware and software including amplifiers and filters, digital signal analysis and instrumentation settings. Other sections cover the topics such as temporary storage, trigger and delay line, averaging, electrode types, stimulation techniques for optimal and standardised EMG examinations, and the artefacts electromyographers may face and safety rules they should follow. Finally, storage of data and databases, report generators and external communication are summarized. (C) 2019 The Author(s). Published by Elsevier B.V. on behalf of International Federation of Clinical Neurophysiology.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
EMG, Instrumentation, Filters, Amplifiers, Trigger and delay line, EMG averaging, EMG electrodes, EMG artefacts, Electrical safety, Databases
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-402328 (URN)10.1016/j.clinph.2019.07.025 (DOI)000502603500034 ()31761717 (PubMedID)
Available from: 2020-01-14 Created: 2020-01-14 Last updated: 2020-01-14Bibliographically approved
Alix, J. J. P., Neuwirth, C., Gelder, L., Burkhardt, C., Castro, J., de Carvalho, M., . . . Weber, M. (2019). Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings. Clinical Neurophysiology, 130(5), 666-674
Open this publication in new window or tab >>Assessment of the reliability of the motor unit size index (MUSIX) in single subject "round-robin" and multi-centre settings
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2019 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 130, no 5, p. 666-674Article in journal (Refereed) Published
Abstract [en]

Objective: The motor unit size index (MUSIX) is incorporated into the motor unit number index (MUNIX). Our objective was to assess the intra-/inter-rater reliability of MUSIX in healthy volunteers across single subject "round robin" and multi-centre settings.

Methods: Data were obtained from (i) a round-robin assessment in which 12 raters (6 with prior experience and 6 without) assessed six muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis and abductor hallucis) and (ii) a multi-centre study with 6 centres studying the same muscles in 66 healthy volunteers. Intrafinter-rater data were provided by 5 centres, 1 centre provided only intra-rater data. Intrafinter-rater variability was assessed using the coefficient of variation (COV), Bland-Altman plots, bias and 95% limits of agreement.

Results: In the round-robin assessment intra-rater COVs for MUSIX ranged from 7.8% to 28.4%. Inter-rater variability was between 7.8% and 16.2%. Prior experience did not impact on MUSIX values. In the multi-centre study MUSIX was more consistent than the MUNIX. Abductor hallucis was the least reliable muscle.

Conclusions: The MUSIX is a reliable neurophysiological biomarker of reinnervation.

Significance: MUSIX could provide insights into the pathophysiology of a range of neuromuscular disorders, providing a quantitative biomarker of reinnervation.

Place, publisher, year, edition, pages
ELSEVIER IRELAND LTD, 2019
Keywords
Motor unit number index, Motor unit size index, Motor unit, Motor neuron, Amyotrophic lateral sclerosis, Electrophysiology
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-382374 (URN)10.1016/j.clinph.2019.01.020 (DOI)000463537100007 ()30870802 (PubMedID)
Available from: 2019-04-25 Created: 2019-04-25 Last updated: 2019-04-25Bibliographically approved
Sanders, D. B., Arimura, K., Cui, L., Ertas, M., Farrugia, M. E., Gilchrist, J., . . . Stålberg, E. (2019). Guidelines for single fiber EMG. Clinical Neurophysiology, 130(8), 1417-1439
Open this publication in new window or tab >>Guidelines for single fiber EMG
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2019 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 130, no 8, p. 1417-1439Article in journal (Refereed) Published
Abstract [en]

This document is the consensus of international experts on the current status of Single Fiber EMG (SFEMG)and the measurement of neuromuscular jitter with concentric needle electrodes (CNE - CN-jitter). The panel of authors was chosen based on their particular interests and previous publications within a specific area of SFEMG or CN-jitter. Each member of the panel was asked to submit a section on their particular area of interest and these submissions were circulated among the panel members for edits and comments. This process continued until a consensus was reached. Donald Sanders and Erik Stalberg then edited the final document.

Place, publisher, year, edition, pages
ELSEVIER IRELAND LTD, 2019
Keywords
Single fiber EMG, Jitter, Fiber density, Neuromuscular transmission, Neuropathy, Myopathy
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-390509 (URN)10.1016/j.clinph.2019.04.005 (DOI)000473588400033 ()31080019 (PubMedID)
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Nandedkar, S. D., Barkhaus, P. E. & Stålberg, E. (2019). Motor unit number index (MUNIX) and compound muscle action potential amplitude: A reappraisal [Letter to the editor]. Clinical Neurophysiology, 130(10), 2010-2011
Open this publication in new window or tab >>Motor unit number index (MUNIX) and compound muscle action potential amplitude: A reappraisal
2019 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 130, no 10, p. 2010-2011Article in journal, Letter (Other academic) Published
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-395629 (URN)10.1016/j.clinph.2019.07.021 (DOI)000485832400036 ()31416706 (PubMedID)
Available from: 2019-10-23 Created: 2019-10-23 Last updated: 2019-10-23Bibliographically approved
Stålberg, E., van Dijk, H., Falck, B., Kimura, J., Neuwirth, C., Pitt, M., . . . Zwarts, M. (2019). Standards for quantification of EMG and neurography. Clinical Neurophysiology, 130(9), 1688-1729
Open this publication in new window or tab >>Standards for quantification of EMG and neurography
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2019 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 130, no 9, p. 1688-1729Article, review/survey (Refereed) Published
Abstract [en]

This document is an update and extension of ICCN Standards published in 1999. It is the consensus of experts on the current status of EMG and Neurography methods. A panel of authors from different countries with different approach to routines in neurophysiological methods was chosen based on their particular interest and previous publications. Each member of the panel submitted a section on their particular area of interest and these submissions were circulated among the panel members for edits and comments. This process continued until a consensus was reached. The document covers EMG topics such as conventional EMG, Macro EMG, applications of surface EMG and electrical impedance myography. Single Fiber EMG is not included, since it is the topic in a separate IFCN document. A neurography section covers topics such as motor and sensory neurography, F wave recordings, H-reflex, short segment recordings, CMAP scan and motor unit number methods. Other sections cover repetitive nerve stimulation and Pediatric electrodiagnostic testing. Each method includes a description of methodologies, pitfalls, and the use of reference values. Clinical applications accompany some of these sections.

Keywords
EMG, Neurography, Macro EMG, Electrical impedance myography, Mune, MScan, Pediatric neurophysiology, Repetitive nerve stimulation
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-392894 (URN)10.1016/j.clinph.2019.05.008 (DOI)000478689300029 ()31213353 (PubMedID)
Available from: 2019-09-10 Created: 2019-09-10 Last updated: 2019-09-10Bibliographically approved
Nandedkar, S. D., Sanders, D. B., Hobson-Webb, L. D., Billlakota, S., Barkhaus, P. E. & Stålberg, E. (2018). Estimation of Reference Intervals for Transcranial Magnetic Stimulation: Derived Parameters Via the Hoffman Indirect Method Reply [Letter to the editor]. Muscle and Nerve, 58(4), E31-E32
Open this publication in new window or tab >>Estimation of Reference Intervals for Transcranial Magnetic Stimulation: Derived Parameters Via the Hoffman Indirect Method Reply
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2018 (English)In: Muscle and Nerve, ISSN 0148-639X, E-ISSN 1097-4598, Vol. 58, no 4, p. E31-E32Article in journal, Letter (Other academic) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-368370 (URN)10.1002/mus.26198 (DOI)000446523300005 ()
Available from: 2018-12-04 Created: 2018-12-04 Last updated: 2018-12-04Bibliographically approved
Nandedkar, S. D., Barkhaus, P. E., Stålberg, E., Neuwirth, C. & Weber, M. (2018). Motor unit number index: Guidelines for recording signals and their analysis. Muscle and Nerve, 58(3), 374-380
Open this publication in new window or tab >>Motor unit number index: Guidelines for recording signals and their analysis
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2018 (English)In: Muscle and Nerve, ISSN 0148-639X, E-ISSN 1097-4598, Vol. 58, no 3, p. 374-380Article in journal (Refereed) Published
Abstract [en]

Introduction: This study proposes guidelines for motor unit number index (MUNIX) recording and analysis. Methods: MUNIX was measured in control participants and in patients with amyotrophic lateral sclerosis. Changes in MUNIX values due to E1 electrode position, number of surface electromyography interference pattern (SIP) epochs, SIP epoch duration, force of contraction, and outlier data points were investigated. Results: MUNIX depends on optimized compound muscle action potential (CMAP) amplitude. Individual muscles showed variations when the number of epochs was low or when the SIP duration was short. Longer SIP duration allowed better recognition of artifacts. MUNIX results were affected by SIP values at all force levels but was more affected when SIP area was low. Discussion: We recommend changing the E1 electrode position to maximize CMAP amplitude. Twenty or more SIP signals of 500-ms duration should be recorded by using force levels ranging from slight to maximum. Traces should be reviewed to identify and exclude signals with tremor or solitary spikes.

Keywords
artifacts, compound muscle action potential, guidelines, motor unit number index, MUNIX, surface EMG interference pattern, tremor
National Category
Physiology
Identifiers
urn:nbn:se:uu:diva-365670 (URN)10.1002/mus.26099 (DOI)000444079300009 ()29427557 (PubMedID)
Available from: 2018-11-14 Created: 2018-11-14 Last updated: 2018-11-14Bibliographically approved
Nandedkar, S. D., Sanders, D. B., Hobson-Webb, L. D., Billakota, S., Barkhaus, P. E. & Stålberg, E. (2018). THE EXTRAPOLATED REFERENCE VALUES PROCEDURE: THEORY, ALGORITHM, AND RESULTS IN PATIENTS AND CONTROL SUBJECTS. Muscle and Nerve, 57(1), 90-95
Open this publication in new window or tab >>THE EXTRAPOLATED REFERENCE VALUES PROCEDURE: THEORY, ALGORITHM, AND RESULTS IN PATIENTS AND CONTROL SUBJECTS
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2018 (English)In: Muscle and Nerve, ISSN 0148-639X, E-ISSN 1097-4598, Vol. 57, no 1, p. 90-95Article in journal (Refereed) Published
Abstract [en]

Introduction: Reference values (RVs) are required to separate normal from abnormal values obtained in electrodiagnostic (EDx) testing. However, it is frequently impractical to perform studies on control subjects to obtain RVs. The Extrapolated Reference Values (E-Ref) procedure extracts RVs from data obtained during clinically indicated EDx testing. We compared the E-Ref results with established RVs in several sets of EDx data.

Methods: The mathematical basis for E-Ref was explored to develop an algorithm for the E-Ref procedure. To test the validity of this algorithm, it was applied to simulated and real jitter measurements from control subjects and patients with myasthenia gravis, and to nerve conduction studies from patients with various conditions referred for EDx studies.

Results: There was good concordance between E-Ref and RVs for all evaluated data sets.

Discussion: E-Ref is a promising method to develop RVs.

Keywords
CMAP amplitude, distal latency, extrapolated normal, jitter, normal values, reference values
National Category
Neurosciences Neurology
Identifiers
urn:nbn:se:uu:diva-339758 (URN)10.1002/mus.25606 (DOI)000417762300033 ()28181271 (PubMedID)
Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-02-02Bibliographically approved
Feresiadou, A., Casar Borota, O., Dragomir, A., Oldfors, C. H., Stålberg, E. & Oldfors, A. (2018). Tubular aggregates in congenital myasthenic syndrome. Neuromuscular Disorders, 28(2), 174-175
Open this publication in new window or tab >>Tubular aggregates in congenital myasthenic syndrome
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2018 (English)In: Neuromuscular Disorders, ISSN 0960-8966, E-ISSN 1873-2364, Vol. 28, no 2, p. 174-175Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
National Category
Neurology Clinical Laboratory Medicine
Research subject
Pathology
Identifiers
urn:nbn:se:uu:diva-356900 (URN)10.1016/j.nmd.2017.11.009 (DOI)000428487300011 ()29311015 (PubMedID)
Funder
Swedish Research Council, 2012-201
Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2020-01-08Bibliographically approved
Neuwirth, C., Barkhaus, P. E., Burkhardt, C., Castro, J., Czell, D., de Carvalho, M., . . . Weber, M. (2017). Motor Unit Number Index (MUNIX) detects motor neuron loss in pre-symptomatic muscles in Amyotrophic Lateral Sclerosis. Clinical Neurophysiology, 128(3), 495-500
Open this publication in new window or tab >>Motor Unit Number Index (MUNIX) detects motor neuron loss in pre-symptomatic muscles in Amyotrophic Lateral Sclerosis
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2017 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 128, no 3, p. 495-500Article in journal (Refereed) Published
Abstract [en]

Objective: Motor Unit Number Index (MUNIX) is a quantitative neurophysiological measure that provides an index of the number of lower motor neurons supplying a muscle. It reflects the loss of motor neurons in patients with Amyotrophic Lateral Sclerosis (ALS). However, it is unclear whether MUNIX also detects motor unit loss in strong, non-wasted muscles. Methods: Three centres measured MUNIX in 49 ALS patients every three months in six different muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis, abductor hallucis) on the less affected side. The decline of MUNIX in initially non-wasted, clinically strong muscles (manual muscle testing, MMT grade 5) was analysed before and after onset of weakness. Results: In 49 subjects, 151 clinically strong muscles developed weakness and were included for analysis. The average monthly relative loss of MUNIX was 5.0% before and 5.6% after onset of weakness. This rate of change was significantly higher compared to ALS functional rating scale (ALSFRS-R) and compound muscle action potential (CMAP) change over 12 months prior to the onset of muscle weakness (p = 0.024). Conclusion: MUNIX is an electrophysiological marker that detects lower motor neuron loss in ALS, before clinical weakness becomes apparent by manual muscle testing. Significance: This makes MUNIX a good biomarker candidate for disease progression and possibly pharmacodynamics responds.

Place, publisher, year, edition, pages
ELSEVIER IRELAND LTD, 2017
Keywords
MUNIX, Pre-symptomatic ALS, Biomarker, Multicentre, ALSFRS-R
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-320836 (URN)10.1016/j.clinph.2016.11.026 (DOI)000397962900016 ()28043769 (PubMedID)
Funder
EU, European Research Council
Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2017-04-26Bibliographically approved
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