EMGer Beware!
EMG and neuromuscular traps in
your waiting room
Shawn Jorgensen
Albany Medical Center
2015 AAPM&R Annual Assembly
Disclosures
• None
The Champ
• 61 year old healthy male referred by PCP for
bilateral upper limb EMG
The Champ
• 18 months of vague left upper limb pain and left
lower limb pain without clear numbness and
tingling
• Complains that his abdomen “sticks out,” has
trouble keeping his posture
The Champ
• No other sensory complaints
• Generalized weakness
• No trouble with vision, hearing, swallowing,
speech, chewing
• No trouble controlling his bowel or bladder
The Champ
• MRI cervical spine 3 months with “disc
problems”
• Followed by one neurosurgeon for the cervical
spine
• Followed by another neurosurgeon for an
acoustic neuroma, no surgery planned
The Champ
• PMH
▫ Acoustic neuroma, congenitally absent left radius and right
kidney
• PSH
▫ Right carpal tunnel release, prostate surgery
• Meds
▫ none
• Family history
▫ No muscle, nerve, or rheumatological problems in the
family that he can recall
• Social history:
▫ Retired high school administrator and former teacher.
Currently coaches golf and assistant coach basketball.
Exercises twice a week, never smoked, drinks socially
The Champ
• Differential (based on history):
▫ Peripheral
 Focal mononeuropathy
 Brachial plexopathy
 Cervical radiculopathy
▫ Central
 Cervical myelopathy
 Intracranial process (right)
The Champ
• Physical exam
▫ General
 Appearing healthy, stated age, congenital left upper limb
deformity
▫ Cranial nerves
 normal II-XII
▫ Motor
 MMT: 5/5 bilateral upper, lower limbs except:




4/5 left wrist extension
2/5 right thumb opposition
4/5 right thumb abduction
4/5 right finger abduction
 No atrophy
 Fasciculations frequent and continuous in biceps, triceps,
quadriceps, lateral abdominal wall
The Champ
• Physical exam
▫ Reflexes




2+ right biceps, triceps, brachioradialis
1+ left triceps; bilateral patella and ankles
0 left biceps, brachioradialis
No Hoffman, Babinski
▫ Sensation
 Pinprick
 Intact bilateral UE/LE, trunk, face
 Vibration
 Felt for 17 seconds at the bilateral toes
▫ Coordination
 No tremor
The Champ
• Differential (based on history and physical)
▫ Diffuse
 Generalized peripheral neuropathy
 Pure motor or with prominent motor involvement
 Neuromuscular junction disorder
 Myopathy
 Motor neuron disease
▫ Focal
 Radiculopathy
 Plexopathy
 Focal mononeuropathy
The Champ
• Studies
▫ Imaging
 MRI cervical spine 3 months earlier
 C5-6 disc osteophyte with right greater than left
foraminal narrowing
 Minor DDD/DJD at other levels
 No significant central stenosis, cord compression, or
myelomalacia
The Champ
• Next step (while in the office)?
▫ EMG
The Champ
• Studies
▫ Motor NCS:
 Right ulnar: nl latency, amplitude, CV, no TA/CB
 Bilateral median: nl latency, amplitude, CV, no
TA/CB
 Right fibular: nl latency, amplitude, CV, no TA/CB
▫ Sensory NCS:
 Right sural: nl peak latency, amplitude
 Bilateral median D4: right prolonged peak latency,
left normal, both amplitudes normal
 Ulnar D4: nl peak latency, amplitudes bilaterally
The Champ
The Champ
• Differential (based on EDX)
▫ Diffuse
▫ Primarily motor
 Motor neuron disease
 LMN only
 Neuromuscular junction disorder
 Myopathy
 With abnormal spontaneous activity
 With large MUAP - chronic
 Neuropathy
 Multifocal motor neuropathy
The Champ
• End of office visit
• Next step
▫ Diagnosis?
▫ More tests?
The Champ
• Diagnosis?
▫ ALS, LMN predominant
The Champ
• ALS
▫ Motor neuron disease
▫ A (primarily) pure motor process with features of
both upper and lower motor neuron death and
dysfunction
The Champ
• EMG/neuromuscular Take Home Point #1
▫ Pure motor processes
 Small portions of nervous system where sensory and
motor fibers diverge
The Champ
• EMG/neuromuscular Take Home Point #1
▫ Pure motor processes
 Must be ANATOMICALLY selective to the motor
system
 Pure motor nerve
 Neuromuscular junction
 Muscle
 Or METABOLICALLY selective to the motor
system
 Motor neuron diseases
 Multifocal motor neuropathy
 AMAN (pure motor GBS)
Case #1 - The Champ
• EMG/neuromuscular Take Home Point #1
▫ Pure motor processes
 Rare (and often bad)
The Champ
• ALS
▫ Presentation
 History
 Often complain of loss of a functional task, rather than
weakness
▫ “weakness”=fatigue, loss of specific function=weakness
(Amato 2008)
 Initial weakness
▫ 1/3 bulbar
▫ 1/3 upper limbs
▫ 1/3 lower limbs (Chancellor 1993)
 Often focal atrophy without sensory complaints
The Champ
• ALS
▫ Presentation
 Physical examination
Clinical pearl!
 Upper and lower motor neuron signs
▫ Upper
▫ Weakness, clumsiness, spasticity, increased MSR, Hoffman,
Babinski
▫ Preserved reflexes in an atrophic limb is considered an
increased reflex! (Rowland 1995)
▫ Lower
▫ Weakness, atrophy, flaccidity, decreased MSR, fasciculations
The Champ
• EMG/neuromuscular Take Home Point #2
▫ Upper and lower motor neuron signs together
 Most likely:
 ALS
 Radiculomyelopathy
The Champ
• EMG/neuromuscular Take Home Point #2
▫ Upper and lower motor neuron signs together
 Radiculomyelopathy
 When both are seen, it is your next job to rule this out –
treatable
▫ Unlikely if there is:
▫ No sensory signs
▫ Prominent bulbar signs
▫ UMN signs ROSTRAL to LMN signs
• Lesion at the cervical cord
▫ LMN at the site of injury
▫ UMN below the injury
▫ UMN always below LMN
• Clinically Probable ALS
• Is defined on clinical or electrophysiological
evidence by LMN and UMN signs in at least two
regions with some UMN signs necessarily rostral to
(above) the LMN signs
• Clinically Possible ALS
• Is defined when clinical or electrophysiological signs
of UMN and LMN dysfunction are found in only one
region: or UMN signs are found alone in two or
more regions; or LMN signs are found rostral to
UMN signs. Neuroimaging and clinical laboratory
studies will have been performed and other
diagnoses must have been excluded.
(de Carvalho 2008)
•Just get the MRI!!
The Champ
• EMG/neuromuscular Take Home Point #2
▫ Upper and lower motor neuron signs together
 ALS without UMN signs?
 On presentation
▫ Increased reflexes about ½
▫ Babinski about 1/3 (Gubbay 1995)
• What is in the picture
above:
▫ A) MUAP
▫ B) Fasciculation potential
▫ C) You can’t actually tell
without seeing if it live to
see if there is a regular
pattern of firing and if the
waveform changes every
time or is the same
morphology and size
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 Randomly occurring isolated MUAP
 Does not have a regular firing pattern
 Not the same one back to back
 Often visible if occurring near the surface – others
deep, only dx with NEE or US (Misawa 2011)
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 Differential diagnosis (Dumitru 2002)
 LMN injury
▫
▫
▫
▫




Radiculopathy
Plexopathy
Peripheral neuropathy
Motor neuron disease
Tetany
Hyperthyroidism
Viral illnesses
Medications
▫ Mestinon
 NORMAL VARIANT!!!
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 NORMAL VARIANT!!!
 70% of healthy patients
 Anxiety, fatigue, heavy exercise, coffee, smoking all
increase likelihood in normal individuals
(Blexrud 1993)
 Majority in the foot intrinsics or gastroc-soleus
(Dumitru 2002)
• Is the fasciculation
potential shown here:
Otherwise, they are
distinguished by the
presence of other signs of
LMN injury such as
abnormal spontaneous
activity and neurogenic
MUAP
▫ A) benign
▫ B) malignant
▫ C) You can’t actually tell
with standard needle EMG.
There have been attempts
based on polyphasicity but
they are not reliable.
SFEMG can tell malignant
ones by increased jitter and
blocking.
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 Relevance
 Very difficult to distinguish “malignant” from “benign”
fasciculations in isolation
▫ Cannot be done reliably with needle EMG
▫ Increased jitter and/or blocking = abnormal
(Dumitru 2002)
 Importance dictated primarily by the “company that
they keep”
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 Relevance (Blexrud 1993)
 121 patients at Mayo clinic followed diagnosed with
benign fasciculation syndrome by normal neurological
exam and EMG (except fasciculations)
 NONE developed symptomatic motor neuron disease
in follow up phone calls 2-32 years after
The Champ
• EMG/Neuromuscular Take Home Point #3
▫ Fasciculations
 Relevance
 With a normal neurological exam and normal EMG
▫ Unlikely motor neuron disease
 In setting of weakness or signs of motor axon loss on
needle EMG
▫ Likely motor neuron disease
 Motor neuron disease almost never presents with chief
complaint of fasciculations
▫ 3% (Gubbay 1985)
The Champ
• ALS
▫ Diagnostic studies
 No imaging or lab study can diagnose sporadic ALS
 In a patient with a suspicious clinical and EDX
presentation, no lab test can rule out ALS
(Brooks 2000)
The Champ
• ALS
▫ Diagnostic studies
 Almost every case of suspected ALS gets:
 EDX
▫ document evidence of widespread denervation, both active
and subacute-chronic
▫ exclude neuropathies, especially MMN
 MRI
▫ Bulbar signs – brain
▫ No bulbar signs – cervical spine
▫ OK to do both
The Champ
• ALS
▫ Diagnostic errors
 False positives (diagnosed with ALS but don’t have it)
 5-10% of cases
 About half have a treatable diagnosis, such as mulitfocal
motor neuropathy or a cervical radiculomyelopathy
(Davenoport 1996)
The Champ
• ALS
▫ Diagnostic errors
 False negatives (diagnosis of ALS missed)
 Nearly 50% of cases (Belsh 1990)
 Usually lumbar and cervical stenosis
 About 30% have unnecessary surgery (Belsh 1996)
The Champ
• Summary
▫ Pure motor processes are rare and often bad
▫ Upper and lower motor neuron findings in the
same patient are rare and a radiculomyelopathy
has to be excluded
▫ Fasciculations with abnormal EMG/exam are
often motor neuron disease; with a normal
EMG/exam are usually benign
The Champ
• Post script
▫ Work up for LMN predominant ALS
 CK, serum immunofixation, AChR antibodies,
copper, ceruloplasmin, zinc, CBC, Lyme and West
Nile virus serology, Anti GM-1 antibodies
 All normal except CK 432
▫ 2nd level workup for LMN predominant ALS
 Genetic testing for SMA-IV - declined
The Champ
• Post script:
▫ 2nd opinion locally
 Suspicious for Kennedy disease – genetic testing negative
▫ 3rd opinion – secondary academic center
 LMN predominant ALS
 Enrolled in local ALS multidisciplinary center
▫ 4th opinion – tertiary academic center
 Noted upgoing right toe, maintained reflexes in atrophic
limb
 Likely ALS
 Investigating clinical trials
The Champ
• Thank you!!
The Champ
• Bibliography
▫
▫
▫
▫
▫
▫
▫
▫
▫
▫
▫
Amato AA, Russel lJA. Approach to the Patient with Neuromuscular Disease. In: Amato AA, Russell JA
(ed)., Neuromuscular Disorders., 1st edn. McGraw-Hill, New York, pp. 3-16.
Belsh, J.M. and P.L. Schiffman, Misdiagnosis in patients with amyotrophic lateral sclerosis. Arch Intern
Med, 1990. 150(11): p. 2301-5.Belsh, J.M. and P.L. Schiffman, The amyotrophic lateral sclerosis (ALS)
patient perspective on misdiagnosis and its repercussions. J Neurol Sci, 1996. 139 Suppl: p. 110-6.
Blexrud MD, Windebank AJ, Daube JR: Long-term follow-up of 121 patients with benign fasciculations, Ann
Neurol 34(4):622–625, 1993
Brooks BR, Miller RG, Swash M, et al: El Escorial revisited: revised criteria for the diagnosis of amyotrophic
lateral sclerosis, Amyotroph Lateral Scler Other Motor Neuron Disord 1(5):293–299, 2000.
Chancellor, A.M., et al., The prognosis of adult-onset motor neuron disease: a prospective study based on the
Scottish Motor Neuron Disease Register. J Neurol, 1993. 240(6): p. 339-46.
Davenport, R.J., et al., Avoiding false positive diagnoses of motor neuron disease: lessons from the Scottish
Motor Neuron Disease Register. J Neurol Neurosurg Psychiatry, 1996. 60(2): p. 147-51.de Carvalho, M., et
al., Electrodiagnostic criteria for diagnosis of ALS. Clin Neurophysiol, 2008. 119(3): p. 497-503.
Dumitru D, Zwarts MJ. Needle Electromyography. In: Dumitru D, Amato AA, Zwarts MJ, Electrodiagnostic
Medicine, 2nd edn. Hanley & Belfus, Inc, Philadelphia, pp. 278-279.
Gubbay SS, Kahana E, Zilber N, et al: Amyotrophic lateral sclerosis. A study of its presentation and prognosis,
J Neurol 232(5):295–300, 1985. Brooks 2000
Haverkamp LJ, Appel V, Appel SH: Natural history of amyotrophic lateral sclerosis in a database population.
Validation of a scoring system and a model for survival prediction, Brain 118(3):707–719, 1995.
Misawa, S., et al., Ultrasonographic detection of fasciculations markedly increases diagnostic sensitivity of
ALS. Neurology, 2011. 77(16): p. 1532-7.
Rowland LP. Amyotrophic lateral sclerosis. In: Rowland, LP (ed), Merrit’s Textbook of Neurology, 9th edn.
Williams and Wilkins, Baltimore, pp. 744-749.