uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Stålberg, Erik
Alternative names
Publications (10 of 75) Show all publications
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
Show others...
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
Show others...
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
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
Show others...
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
Show others...
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
Show others...
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
Show others...
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
Show others...
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: 2019-04-02Bibliographically 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
Show others...
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
Stålberg, E., Sanders, D. B. & Kouyoumdjian, J. A. (2017). Pitfalls and errors in measuring jitter. Clinical Neurophysiology, 128(11), 2233-2241
Open this publication in new window or tab >>Pitfalls and errors in measuring jitter
2017 (English)In: Clinical Neurophysiology, ISSN 1388-2457, E-ISSN 1872-8952, Vol. 128, no 11, p. 2233-2241Article, review/survey (Refereed) Published
Abstract [en]

The safety factor of neuromuscular transmission can be assessed by measuring the neuromuscular jitter, which reflects the time variability of processes in the motor end-plate. Jitter is increased in any condition with disturbed end-plate function, such as myasthenic conditions and ongoing reinnervation. Jitter is increasingly being measured with concentric needle (CN) electrodes, which are more prone to artefacts than single fiber EMG recordings. The objective of this review is to identify and demonstrate pitfalls that can be seen with CN jitter measurements, made with both voluntary activation and electrical stimulation. With voluntary activation, errors are caused by poor signal quality; inappropriate time reference points on the signal; an irregular firing rate; and signals with dual latencies, i.e., "flip-flop." With electrical stimulation, additional errors result from insufficient stimulation intensity; from abrupt change in firing rate; and from axon reflexes. Many pitfalls cannot be avoided during recording and can only be detected during post-processing. It is critical to be aware of these artefacts when measuring jitter with CN electrodes. (C) 2017 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Keywords
SFEMG, Jitter, Myasthenia gravis, Axon reflex, Electrical stimulation, Artefacts
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-376989 (URN)10.1016/j.clinph.2017.09.001 (DOI)000415788100017 ()29017138 (PubMedID)
Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-03-08Bibliographically approved
Erik, S. (2016). Between genetics and biology. Is ENMG useful in peripheral neuropathy diagnosis and management?. Paper presented at International Meeting of the French-Society-of-Neurology, OCT 20-21, 2016, Paris, FRANCE. Revue neurologique (Paris), 172(10), 627-631
Open this publication in new window or tab >>Between genetics and biology. Is ENMG useful in peripheral neuropathy diagnosis and management?
2016 (English)In: Revue neurologique (Paris), ISSN 0035-3787, E-ISSN 2213-0004, Vol. 172, no 10, p. 627-631Article in journal (Refereed) Published
Abstract [en]

Neurography and EMG are complementary techniques used in the diagnosis and monitoring of neuropathies. Both assess function of the peripheral nervous system and provide clinically useful information regarding the functional status of peripheral nerves. This information is not readily obtainable using biochemical, genetic or imaging techniques. I will discuss the role of these techniques in the diagnosis and management of neuropathies and some limitations of these techniques. These methods are routinely used in an EMG lab. These are most useful when used in conjunction with clinical examination to answer a well-defined clinical question. Reference values are required for interpretation of the data.

Keywords
Neurography, Motor conduction, Sensory conduction, Axonal neuropathy, Demyelinating neuropathy, Motor unit counting, EMG
National Category
Neurosciences Neurology
Identifiers
urn:nbn:se:uu:diva-310679 (URN)10.1016/j.neurol.2016.07.021 (DOI)000387735200013 ()27638136 (PubMedID)
Conference
International Meeting of the French-Society-of-Neurology, OCT 20-21, 2016, Paris, FRANCE
Available from: 2017-01-02 Created: 2016-12-19 Last updated: 2018-01-13Bibliographically approved
Organisations

Search in DiVA

Show all publications