TC33 Grisold

EMG-Course
WCN 2013
wolfgang.grisold@wienkav.at
department neurology, KFJ
hospital Vienna
WCN 2013, Vienna
Disclosures
• There are no commercial disclosures.
• The author is a member of the UEMS/EBN and a trustee of the WFN
EMG - Learning
objectives
• This is a practical basic approach towards electromyography (EMG) and
includes:
• Electromyography (EMG)
• Spontaneous activity
• Motor unit potentials
• Recruitment and interference pattern
• Single fiber EMG
• Pitfalls and cautions
• Reporting
EMG
• Needle
• Recording area
• Needle insertion
• Rest, relaxation, posture
• EMG screen
• Loudspeaker
• EMG equipment (amplifier, filter,
•
recording)
• Report
Needle types
Kimura 45
Electrophysiology is an
extension of clinical neurology
Neurogenic
Myopathic
NMJ
Neuronopathy
Radiculopathy
Plexopathies
Gen. neuropathies
mononeuropathies
Generalized
Proximal
Distal
Focal
eurogenic
Postsynaptic: MG
Presynaptic:
LEMS,
Neuromyotonia
NCV
mononeuropathies
NCV/Rep.
Rep.
EMG
distribution
acute/chronic
myotonic
discharges
EMG
Neuromyotonia
EMG
Innervation
denervation
„reinnervation“
distribution
sfSSFEMG
SFEMG
Central
EMG
Recruitment
Elements of EMG
analysis
• Spontaneous activity
• MUAP (motor unit potentials)
• IF pattern (recruitment, interference pattern)
Spontaneous activity
• Endplate potentials
• Fibrillation
• Positive sharp wave
• Fasciculation
• CRD
• Myotonia/Pseudomyotonia
Endplate
Fibrillation
Kimura 312
Positive sharp wave
Fibrillation1
Fibrillation 2
Fasciculation
ELECTROMYOGRAPHY IN CLINICAL PRACTICE ISBN: 978-0-323-02899-8
Copyright © 2007 by Mosby, Inc., an affiliate of Elsevier Inc.
Complex
repetitive
discharges
CRD
CRD
Myotonic
dystrophy
Myokymia
Douplets
Neuromyotonia
Cramps
MUAP
• Duration
• Amplitude
• Rise Time
• Spike duration
• Phase and Turns
• Stability and variation
Types of MUAPS
Polyphasia
Long duration
Katiriji 76
Nascent (regen.)
From:Lawrence J. Kagen (Editor) The Inflammatory Myopathies
Analysis
• Manual
• Computer-Assisted Quantitative Analysis of User Selected MUP
• Several others (eg MUNE)
The concept of normal values
Recruitement/“Interference pattern
From: J Neurol Neurosurg Psychiatry 2005;76:ii32ii35 doi:10.1136/jnnp.2005.069211
Interference pattern Turn/Amplitude
Single Fiber EMG:
SFEMG
• Identify the presence of a disorder of neuromuscular transmission when other
electrophysiologic assessments are normal.
• Follow the course of mild defects of neuromuscular transmission.
• Identify the presence of signs of regeneration in neurogenic and myopathic
• Fiber density
• Calculate muscle fiber membrane propagation velocity
• Fiber density reflects the packing density of
muscle fibers within the recording area of the
single fiber electrode. It correlates with the degree
of motor unit potential polyphasia in concentric
needle EMG recordings. Fiber density is increased
in neurogenic and myopathic disease.
• Jitter measures the latency variability of muscle
fiber action potentials within the same motor unit.
It reflects the variability in rise time of the end
plate potential, providing a sensitive indicator of a
mild defect of neuromuscular transmission.
What do you need ?
• SFEMG needle or
• Concentric needle
• Spontaneous vs simulated
• Software
Jitter
Artefacts
• Electrode noise
• Amplifier noise
• Defect recording electrodes
• Movement artifact
• Electrostatic and magnetic interference
• Radio- and mobile phone interference
EMG complications
• Anticoagulation and bleeding
• Lymph edema and skin
• Infections
• Peripleural muscles
• Pacemaker
• Obese patients
• Low pain tolerance
• Muscle Nerve: 1. Al-Shekhlee A, et al. Iatrogenic complications and risks of
nerve conduction studies and needle electromyography. Muscle Nerve
2003;27:517-526.
Examples of Diseases
• Localizing
• Distribution
• Myopathies
• Polygraphy
• Interventions
Interventions
• Botulinus toxin treatment
• Infiltration
• Pain therapy
Text
Reporting normal Rt biceps brachii
• Rt. biceps brachii muscle
• Conditions: good, impression: normal muscle,
no atrophy
• At 6/6 positions no spontaneous activity. The
mean duration of the MUAPs is 10,5 ms (age
related normal value 10 ms), which
corresponds to + 5 %. Maximal contraction
shows an interference pattern with an
amplitude of 2 mV.
Verlag/Wien
The ABC of EMG. A Practical
Introduction on Kinesiological
Electromyography Peter
Konrad. Noraxon INC. USA.
Cohen JA et al. Peripheral
Nerve and Muscle
Disease.Oxford University
Press 2009
Dr Mike Bradley . Atlas of
musculoskeletal ultrasound
anatomy. Stanmore, Middlesex
LONDON SAN FRANCISCO
cambridge
Al-Shekhlee A, et al. Iatrogenic
complications and risks of
nerve conduction studies and
needle electromyography.
4.
Shapiro BE, Preston DC. Electromyography. Saunders, Elsevier, 2005
5.
Mills KR,The basics of electromyography. J Neurol Neurosurg Psychiatry 2005;76:ii32-ii35 doi:10.1136/jnnp.2005.069211
6.
Eva L. Feldman, Wolfgang Grisold, James W. Russell, Udo A. Zifko. Atlas of Neuromuscular Diseases.A Practical Guideline.
(First edition). 2005 Springer-Verlag/Wien
7.
The ABC of EMG. A Practical Introduction on Kinesiological Electromyography Peter Konrad. Noraxon INC. USA.
8.
Cohen JA et al. Peripheral Nerve and Muscle Disease.Oxford University Press 2009
9.
Dr Mike Bradley . Atlas of musculoskeletal ultrasound anatomy. Stanmore, Middlesex LONDON SAN FRANCISCO
cambridge
References
10. Al-Shekhlee A, et al. Iatrogenic complications and risks of nerve conduction studies and needle electromyography.
Muscle Nerve 2003;27:517-526.
11. Rubin, MD Katirji, Bashar. Electromyography in clinical practice: a case study approach/Bashar Katirji—2nd ed.2007 by
Mosby, Inc.,
12. Ludin HP.Praktische Elektromyographie. Enke Verlag, 3. Auflage. Stuttgart, 1988.
13. Kimura J. ELECTRODIAGNOSIS IN DISEASES OF NERVE AND MUSCLE.(3rd ed). OXFORD UNIVERSITY PRESS .2001
14. Daube JL.Devon I. Rubin,CLINICAL NEUROPHYSIOLOGY Third Edition. Oxford University Press 2009.