Compliance with the provisions in this policy may be monitored and addressed
through post payment data analysis and subsequent medical review audits.

****

**History/Background and/or General Information**  
  
Electrodiagnostic (EDX) studies are an extension of a clinical assessment for
evaluation of an assortment of focal and generalized neuromuscular disorders
of the peripheral nervous system and the central nervous system. Assessment of
these disorders generally includes a focused neuromuscular history and
physical examination, the development of a differential diagnosis and EDX
studies. The EDX studies are founded on the history and physical and suspected
diagnosis and are followed by an assessment of muscles and nerves using nerve
conduction studies (NCSs) and needle electromyography (NEMG), and the
determination of a final diagnosis. The NCSs are performed and interpreted
with the NEMG on site and in real time.1-2 NCSs may be conducted without NEMG
in some situations, such as entrapment neuropathies, but this should be the
exception rather than the normal practice pattern. When NCSs are conducted
without NEMG, beneficial data that may be important in determining an accurate
diagnosis are commonly missing. The results of the NEMG studies can frequently
provide an alternative etiology or coexisting disorder in the case of a
suspected disorder.1,3

EDX studies provide beneficial information regarding location, chronicity,
severity, and pathophysiology to help determine a diagnosis and monitor a
disease process in response to therapy.1

**Covered Indications**

****

  1. NCSs and NEMG are considered medically reasonable and necessary when they are performed and interpreted at the same time, on site, and in real time for any of the following circumstances:

  1.     1. Plexopathy - including idiopathic, traumatic, inflammatory or infiltrative, radiation-induced,1 brachial plexopathies (e.g., neuralgic amyotrophy, thoracic outlet syndrome), and lumbosacral plexopathies (e.g., diabetic, non-diabetic lumbosacral radiculoplexus neuropathy)4
    2. Focal neuropathies (e.g., entrapment neuropathies or compressive lesions/syndromes such as carpal tunnel syndrome,5-8 ulnar neuropathy,9-10 tarsal tunnel syndrome,11 femoral neuropathy, saphenous neuropathy, lateral femoral cutaneous neuropathy, peroneal (fibular) neuropathy, tibial neuropathies, sciatic neuropathy)1,12-18
    3. Generalized neuropathies such as metabolic (e.g., diabetic, uremic), toxic, hereditary or immune-mediated1,19-20
    4. Motor neuron disease (e.g., amyotrophic lateral sclerosis [ALS] or Lou Gehrig's disease)1,21-22
    5. Myopathy - including inflammatory myopathies such as polymyositis and dermatomyositis, congenital myopathies,23 congenital and hereditary dystrophic and nondystrophic myopathies, including myotonic muscular dystrophy, acquired myopathies (drug induced myopathy associated with statins, thyroid related), metabolic myopathies (e.g., McArdle disease)1,24
    6. Myotonic disorders (e.g., drug induced myotonia)25
    7. Neuromuscular junction disorders (e.g., myasthenia gravis, Lambert-Eaton myasthenic syndrome, botulism)1,26-27
    8. Polyneuropathies1,28-30
    9. Radiculopathy - cervical,31 thoracic or lumbosacral1,32-33
    10. Spinal cord disorders31 (i.e., myelopathy)
    11. Symptom-based presentations such as "pain in limb", weakness, cramping/twitching, disturbance of skin sensation or "paresthesia" when appropriate pre-test evaluations are inconclusive, and the clinical assessment unequivocally supports the need for the study1
    12. Traumatic nerve lesions, for diagnosis and prognosis1

  2. Neuromuscular Junction (NMJ) Testing is considered medically reasonable and necessary for any of the following conditions:  
  

    1. Botulinum toxicity1,3
    2. Motor neuron disease (e.g., ALS or Lou Gehrig's disease)1
    3. Myopathy1,34
    4. Myasthenia gravis27,34-35
    5. Myasthenic syndrome (e.g., Lambert-Eaton myasthenic syndrome)1,3

  3. NCSs when performed **without** NEMG are considered medically reasonable and necessary for the following situations:

  1.     1. Individuals treated with anticoagulants35-36 such as warfarin (Coumadin), rivaroxaban (Xarelto), dabigatran (Pradaxa), apixaban (Eliquis), edoxaban (Lixiana), clopidogrel (Plavix), ticagrelor (Brilinta), ticlopidine (Ticlid), prasugrel (Effient), varapaxar (Zontivity), dipyridamole, cilostazol (Pletal)
    2. Individuals with significant lymphedema in the affected extremity36
    3. Individuals being evaluated for carpal tunnel syndrome or tarsal tunnel syndrome3,11
    4. Guidance for botulinum toxin treatment injections when it is difficult to isolate affected muscles1,37  

  4. NEMG when performed **without** NCSs is considered medically reasonable and necessary for the following situations:

  1.     1. Guidance for botulinum toxin treatment injections when it is difficult to isolate affected muscles1,37
    2. Laryngeal neuropathy38
    3. Constipation39
    4. Fecal incontinence39
    5. Lower urinary tract symptoms40-42
    6. Patients with risk factors for urinary retention40-44

  5. Single Fiber Electromyography (SFEMG) is considered medically reasonable and necessary for the following condition:

  *     * Ocular myasthenia45   

**Limitations**

****

The following are considered not medically reasonable and necessary:

  1. EDX studies where the interpretation is delayed and not completed at the time the study is performed2,8,46 The NCS must be performed and interpreted with the NEMG on site and in real time1-2
  2. EDX studies (NCS and NEMG) not performed by a physician or under direct supervision of a physician in the office setting1 (Refer to the CMS IOM Pub 100-02, _Medicare Benefit Policy Manual_ , Chapter 15, Section 80 Requirements for Diagnostic X-Ray, Diagnostic Laboratory, and Other Diagnostic Tests)
  3. Non-invasive EDX studies using portable hand-held devices or automated point of care nerve conduction monitoring systems, which are incapable of real-time waveform display and analysis3,47-53
  4. Testing for polyneuropathy of diabetes in patients without clinical deficits or for the sole purpose of monitoring disease intensity or treatment efficacy3
  5. Quantitative Sensory Testing (QST) (e.g., hot-cold, touch, vibration)54-58
  6. NCSs accomplished with discriminatory devices that use fixed anatomic templates and computer-generated reports used as an adjunct to physical examination routinely on all patients1
  7. Physiologic recording of movement disorder symptoms, including bradykinesia, dyskinesia, and tremor using wearable devices with accelerometers or gyroscopes59
  8. NCSs or EMG for muscle pain without the presence of other abnormalities on examination or in laboratory testing60
  9. NEMG for the following situations: 
    * Definitive diagnosis based on paraspinal NEMG in areas with scar from past surgeries (e.g., previous laminectomies)3
    * Surface electromyography (SEMG)3,61-63
    * Macroelectromyography (macro-EMG)3
    * NEMG for isolated neck or back pain after a motor vehicle accident60

  10. Studies performed beyond the reasonable maximum number of studies recommended in the Current Procedural Terminology (CPT) Codebook, Appendix J, Electrodiagnostic Medicine Listing of Sensory, Motor, and Mixed Nerves. These recommendations are supported by the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM).1 Additional studies may be considered upon redetermination.

Please refer to the CMS IOM Publication 100-03, _Medicare National Coverage
Determinations (NCD) Manual,_ Chapter 1, Part 2, Section 160.23 Sensory Nerve
Conduction Threshold Tests (sNCTs) for additional limitations.

Repeat EDX assessment may be needed in certain circumstances. The frequency
for repeating EDX studies in a given patient by a given EDX provider for a
given diagnosis per year can be reasonably limited. The following number of
studies per 12-month period per diagnosis per provider are suitable: 1) Two
studies for carpal tunnel-unilateral, carpal tunnel-bilateral, radiculopathy,
mononeuropathy, polyneuropathy, myopathy, and NMJ disorders. 2) Three studies
for motor neuron disease and plexopathy. These limits should not apply if the
patient requires assessment by more than one EDX provider (i.e., a second
opinion or an expert opinion at a tertiary care center) in a given year or if
the patient requires evaluation for a second diagnosis in a given year.1

Repeat EDX studies are rare and should not be necessary in a 12-month period
in 80% of all cases.1 Additional studies may be considered upon
redetermination. In such circumstances, the rationale for the repeat study
should be included in the medical record. Comparison with the previous study
findings should be documented.

**Provider Qualifications**

Services provided within the LCD coverage indications will be considered
medically reasonable and necessary when all aspects of care are within the
scope of practice of the provider's professional licensure; and when all
procedures are performed by appropriately trained providers in the appropriate
setting.

**Notice:** Services performed for any given diagnosis must meet all of the
indications and limitations stated in this policy, the general requirements
for medical necessity as stated in CMS payment policy manuals, and all
Medicare Payment rules.

A literature search was conducted using the following key words:
electrodiagnostic study; electrophysiologic study; electromyography; nerve
conduction study (NCS); sensory nerve conduction study; nerve conduction
velocity; quantitative sensory testing. The literature search was filtered to
locate articles within 5-10 years, full-text articles, clinical trials, and
systematic reviews. In general, improved health outcomes of interest include
patient quality of life and function.

Guidelines and consensus statements from the AANEM have been incorporated
throughout the summary of evidence. These guidelines and consensus statements
offer evidence-based recommendations for the evaluation and treatment of
muscle and nerve disorders in the practice of EDX medicine. These
recommendations have been developed in cooperation with physicians who
specialize in neuromuscular and EDX medicine.64

**EDX Studies**

EDX studies are an extension of a clinical assessment for evaluation of an
assortment of focal and generalized neuromuscular disorders of the peripheral
nervous system and the central nervous system. EDX studies provide beneficial
information regarding location, chronicity, severity, and pathophysiology to
help determine a diagnosis and monitor a disease process in response to
therapy.1

An EDX assessment generally includes a focused neuromuscular history and
physical examination, the development of a differential diagnosis and EDX
testing that is founded on the history and physical and suspected diagnosis
followed by an assessment of muscles and nerves using NCSs and needle
electromyography (NEMG), and the determination of a final diagnosis. According
to the standard of care in clinical practice guidelines, these components
cannot be predetermined or standardized.1,46

EDX studies include the following: NEMG, SEMG, NCSs, late responses (i.e.,
H-reflex studies, F-wave studies), NMJ studies, somatosensory evoked
potentials (SEPs), QST and autonomic nervous system function testing.1 In
general, the NCS should be conducted and interpreted with complementary NEMG
on site and in real time.2 The NEMG may provide an alternative etiology or
coexisting disorder in the situation of a suspected disorder. The AANEM
indicates that performing both studies together is vitally important when
assessing patients with suspected radiculopathy, plexopathy, and motor nerve
or motor neuron disease.8,46 NCSs may be conducted without NEMG in some
situations, such as entrapment neuropathies, but this should be the exception
rather than the normal practice pattern.3

**NCS**

Evidence-based literature indicates that NCSs with or without late responses
can be efficient for diagnosing and evaluating the following conditions:
peripheral nerve entrapment13-16; generalized neuropathies19-20;
polyneuropathies28-29; neuromuscular junction disorders26-27; myopathies
including polymyositis, dermatomyositis, and congenital myopathies23; motor
neuron disease21-22; spine disorders and radiculopathy31; and guidance for
botulinum toxin injections when it is difficult to isolate affected muscles.37

**AANEM**

The AANEM1 indicates that a typical NCS should include: 1) Development of a
differential diagnosis based upon an appropriate history and physical
examination; 2) NCS (recording and studying of the electrical responses from
peripheral nerves or the muscles); 3) Completion of indicated NEMG studies to
evaluate the differential diagnosis and to complement the NCS.

_On Site in Real Time_ : The AANEM8 indicates that when performing NCSs the
waveform must be reviewed on site and in real time, with reports prepared
onsite by the examiner, consistent with the American Medical Association's
(AMA) CPT Professional Codebook descriptions. The AANEM defines the use of
the term onsite as that where the history and physical examination,
performance of NCS and NEMG, analysis of electrodiagnostic data and
determination of diagnosis occur in the same location, usually an
electrodiagnostic laboratory. Similarly, real time is defined as that which
allows for information from the history and physical to be integrated with the
performance of testing, allowing for the testing of both NCS and NEMG to be
tailored/modified to the individual situation as needed before leaving the
lab.2

_NCSs_ : NCSs, also referred to as nerve conduction velocity (NCV) studies,
are performed to assess the integrity and diagnose diseases of the peripheral
nervous system. NCSs assess action potentials following peripheral nerve
stimulation which include the speed (conduction velocity and/or latency), size
(amplitude), and shape of the response. Pathological findings include
conduction slowing, conduction block, or reduced response. Results of the NCS
reflect on the integrity and function of the myelin sheath and the axon of a
nerve. Interruption of axon and dysfunction of myelin will both affect NCS
results.1,3

While the stimulation of nerves is similar across all NCSs, the attributes of
motor, sensory, and mixed NCSs are different; a) Motor NCSs are conducted by
applying electrical stimulation at different points along the course of a
motor nerve while recording the electrical response from an appropriate
muscle. Response parameters include amplitude, latency, configuration, and
motor conduction velocity. b) Sensory NCSs are performed by applying
electrical stimulation near a nerve and recording the response from a distant
site along the nerve. Response parameters comprise amplitude, latency, and
configuration. c) Mixed NCSs are achieved by applying electrical stimulation
near a nerve containing both motor and sensory fibers (a mixed nerve) and
recording from a different location along that nerve that also contains motor
and sensory nerve fibers. Response parameters comprise amplitude, latency,
configuration, and motor conduction velocity.1,3

__

_NEMG_ : Allows for interpretation of the muscle's electrical qualities at
rest and during activation. This interpretation includes analysis of the
recruitment pattern and morphology and characteristic sound of motor unit
potentials and spontaneous electrical activity. NEMG studies are interpreted
in real time, as they are being performed. NEMG is performed to exclude,
diagnose, describe, and follow diseases of the peripheral nervous system. NEMG
involves the recording and study of electrical activity of skeletal muscle
using a needle electrode.1,3

__

_H-reflex/F-wave Study_ : Late response (H-reflex and F-wave study) testing is
a type of NCS usually performed on nerves more proximal to the spine. The
H-reflex involves conduction from the periphery to and from the spinal cord.
The H-reflex study involves the assessment of the gastrocnemius/soleus muscle
complex in the calf and is usually performed bilaterally due to the need to
assess symmetrical results in determining abnormalities. The F-wave study is a
late response similar to the H-reflex. F-wave studies are used to assess the
proximal segments of the motor nerve function and are performed in combination
with the examination of motor nerves. Both studies are helpful in diagnosing
conditions of radiculopathies, plexopathies, polyneuropathies (particularly
with multifocal conduction block, Guillain-Barre syndrome or chronic
inflammatory demyelinating polyneuropathy), and proximal mononeuropathies.1
Late response studies are complementary to NCS and are performed during the
same evaluation.

_Conditions Recommended for Electrodiagnostic Testing_ : 1) Focal
neuropathies, entrapment neuropathies, or compressive lesions/syndromes such
as carpal tunnel syndrome, ulnar neuropathies,12 or root lesions, for
localization; 2) Traumatic nerve lesions, for diagnosis and prognosis; 3)
Generalized neuropathies, such as metabolic (i.e., diabetic, uremic, etc.),
toxic, hereditary or immune-mediated; 4) Neuromuscular junction disorders such
as myasthenia gravis, myasthenic syndrome or botulism; 5) Symptom-based
presentations such as "pain in limb", weakness, cramping/twitching,
disturbance of skin sensation or "paresthesia" when appropriate pre-test
evaluations are inconclusive and the clinical assessment unequivocally
supports the need for the study; 6) Radiculopathy-cervical, thoracic,
lumbosacral; 7) Plexopathy - including idiopathic, traumatic, inflammatory or
infiltrative, radiation-induced; 8) Myopathy-including inflammatory myopathies
like polymyositis and dermatomyositis, myotonic disorders, and congenital
myopathies; and 9) Precise muscle location for injection of intramuscular
agents (e.g., botulinum toxin, phenol or other substances for nerve blocking
or chemodenervation).1,3

_NEMG Performed in the Setting of Lymphedema_ : Based on the literature, the
AANEM's position is that there are no contraindications to NEMG in patients
with lymphedema. However, the AANEM believes that reasonable caution should be
taken in performing needle examinations in lymphedematous regions to avoid
complications. Clinical judgment should be used in deciding whether the risk
of complication is greater than the value of the information to be obtained
from the NEMG.36

_NEMG Performed in Patients with Disorders of Hemostasis_ : Based on the
literature, the AANEM's position is that the use of NEMG in patients with and
without increased bleeding risk is safe. However, the AANEM believes that
reasonable caution should be taken in performing NEMG and each case should be
considered individually with regard to the potential benefits of the study
relative to the risks of intramuscular hemorrhage or other bleeding.36

Generally, for NEMG or SFEMG examination in patients with platelets < 50,000
or INR > 1.5, caution should be exerted by using the smallest caliber needle
and using extra pressure/time for hemostasis. Per available literature,
judicious caution should be used if assessment of cranial nerves and
paraspinal muscles would be further undertaken. In addition, muscles that can
possibly lead to remote risk of compartment syndrome like tibialis posterior,
flexor pollicis longus, should be averted in these specific patients that
exceed the above-mentioned criteria.36

**Carpal Tunnel Syndrome (CTS)**

CTS, the most common entrapment neuropathy of the upper extremity, is
generally diagnosed by history and physical assessment, and EDX studies (NCS
and sometimes NEMG) are utilized as objective measures to confirm existence of
a median mononeuropathy. The NCSs verify CTS by identifying impaired median
nerve conduction across the carpal tunnel. The NEMG evaluates pathologic
changes in the muscles innervated by the median nerve.5-6 Evidence-based
clinical practice guidelines recommend EDX studies to confirm a clinical
diagnosis of CTS.7

**Ulnar Neuropathy**

Dy and Mackinnon9 performed a systematic review and meta-analyses of the
literature regarding evaluation and management of ulnar neuropathy.
Compression of the ulnar nerve at the elbow joint is frequently referred to as
cubital tunnel syndrome.10 Evidence-based literature indicates a thorough
clinical history and physical examination and prudent assessment of EDX
studies are useful to help confirm the diagnosis, localize the site and
quantify the grade of compression and in establishing the prognosis of
recovery with nonoperative and operative management in patients with ulnar
neuropathy.9-10 In long-standing or severe compression of the ulnar nerve,
NCSs show a reduction in amplitude that reflects an overall decline in the
number of functioning nerve fibers. NEMG demonstrates abnormal activity during
the insertional phase (indicating muscle denervation), fibrillations during
resting phase (a sine qua non for motor axon loss), and the manifestation of
motor unit action potentials during the recruitment phase (signifying
attempted reinnervation by either collateral sprouting or axonal
reinnervation).9

**Tarsal Tunnel Syndrome (TTS)**

Patel et al11 provides an AANEM practice topic regarding an evidence-based
practice parameter that addresses the effectiveness of EDX testing in the
diagnosis of TTS (tibial neuropathy at the ankle). The AANEM indicates that
NCSs can be beneficial to substantiate the diagnosis of tibial neuropathy at
the ankle. But the efficacy for NEMG in the evaluation of TTS is uncertain.

**Entrapment Neuropathies of the Lower Extremity**

Craig17 provides a review of the literature concerning the use of EDX studies
for entrapment neuropathies of the lower extremity (e.g., femoral neuropathy,
saphenous neuropathy, obturator neuropathy, lateral femoral cutaneous
neuropathy, peroneal (fibular) neuropathy, tibial neuropathies, sciatic
neuropathy, gluteal neuropathies). Evidence-based literature indicates that
the preliminary approach to suspected neurologic injury encompasses a
judicious physical examination to describe the distribution of motor and
sensory loss. Electromyography is utilized to verify and localize the
neurologic injury, evaluate the severity of the injury to facilitate
prognostication, help in developing a management plan, and exclude confounding
or coexisting neurologic injury.17

For femoral neuropathy, NCSs of the femoral nerve can be performed by
stimulating the femoral nerve at the inguinal ligament and recording over the
quadriceps. A comparison can be made with the clinically normal opposite side.
Attaining a compound action potential of at least 50% for the opposite side
indicates a good prognosis for recovery within a year. The NEMG study should
include the quadriceps and the iliopsoas. Anomalies in the iliopsoas indicate
the nerve lesion is within the pelvis.17

In situations of suspected saphenous nerve injury causing saphenous
neuropathy, a NCS may be conducted although these are technically challenging,
and responses can be slight; results should be contrasted with the unaffected
side. Outcomes of a NEMG should be normal and are helpful to rule out femoral
neuropathy, L4 radiculopathy, or a lumbar plexopathy.17

Currently, there is no NCS offered to evaluate the obturator nerve. However,
NEMG is beneficial in verifying suspected obturator neuropathy with
abnormalities in the adductor muscles. If assessing the adductor magnus, it is
vital to appreciate that the sciatic nerve also contributes to its motor
innervation. Evaluation of femoral-innervated muscles and paraspinal muscles
should be conducted to rule out plexus injury or radiculopathy.17

Lateral femoral cutaneous neuropathy may be verified by conducting a NCS and
contrasting results with the opposite side although attaining a response is
technically challenging. Ultrasound may be used to detect nerve location and
enhances the capability to record sensory nerve action potentials. NEMG is
beneficial to rule-out other disorders, such as L2 radiculopathy, high lumbar
plexopathy or femoral neuropathy.17

In situations of suspected peroneal (fibular) neuropathy, a NCS can be
beneficial in locating a peroneal lesion. Peroneal motor conduction to the
extensor digitorum brevis (EDB) muscles should be conducted, stimulating the
nerve at three sites: the anterior ankle, fibular head, and popliteal fossa.18
A NEMG should assess the tibialis anterior, peroneus longus, and biceps
femoris to evaluate the severity of the injury and help guide prognosis.18 It
is essential to realize the EDB muscles can be denervated because of local
trauma or with distal neuropathy.17 In addition, in one-third of people, an
accessory peroneal nerve that arises from the superficial peroneal nerve can
contribute to the EDB. This variation may be detected when the amplitude
acquired when stimulating above the fibular head is greater than when
stimulating below the fibular head and is confirmed by acquiring a response
stimulating behind the lateral malleolus. Peroneal motor conduction may also
be acquired from the anterior tibialis. Contrasting with the opposite side is
useful in calculating the degree of axon loss. Decrease of the superficial
peroneal sensory response signifies a lesion distal to the dorsal root
ganglia. Tibial motor, F-response, and sural nerve studies are beneficial in
ruling out a peripheral neuropathy or a more widespread lesion, such as a
plexopathy or sciatic injury. NEMG assists to further locate the lesion,
exclude other causes of foot drop, and evaluate the severity of the axon
loss.17

When a tibial neuropathy is suspected, EDX testing of suspected tibial lesions
should involve sural sensory responses, which will be variably affected in
proximal tibial lesions. Demonstrable asymmetry with respect to comparing
sural sensory responses between the two limbs can be helpful with borderline
normal responses. A decrease in tibial motor responses to the abductor
hallucis will be observed. When TTS (a common variant of tibial neuropathy) is
suspected, medial and lateral plantar responses should be conducted. These can
be challenging to acquire, particularly with thick calluses or preexisting
peripheral neuropathy. Contrasting with the contralateral limb should be
completed before drawing any conclusions from low or absent responses. NEMG
will show denervation in the medial gastrocnemius or posterior tibialis in
proximal tibial lesions. Mid leg lesions may spare muscles that affect the
long toe flexors and foot intrinsics only. In cases of severe TTS, physical
exam may reveal atrophy of the first dorsal interosseous and adductor hallucis
muscles resultant to pathology of the lateral and medial plantar branches
respectively. Abnormalities of these muscles are also observed in early
peripheral neuropathies so contrasting with the opposite side is recommended.
Differential diagnosis of tibial neuropathy involves S1 radiculopathy, sciatic
neuropathy, and lumbar plexopathy. Therefore, careful physical examination of
hamstring muscles innervated by the tibial branch of the sciatic nerve as well
as nontibial innervated S1 muscles should be performed.17

A NCS in sciatic neuropathy will yield decreased amplitudes of the superficial
peroneal sensory and sural sensory responses. Also, both tibial and peroneal
motor responses will be low, without evidence of a focal conduction block at
the knee. The NEMG assessment is especially effective in localizing the
lesion. Evidence of denervation will be observed in both the peroneal and
tibial divisions and in more proximal hamstring muscles. The short head of the
biceps femoris is particularly beneficial in circumstances in which the
peroneal division is preferentially injured, as it is the only muscle
innervated by the peroneal division while still part of the sciatic nerve
proper. Assessment of other gluteal muscles and paraspinal muscles should be
executed to rule out a more proximal plexus injury or L5-S1 radiculopathy.17

Currently, there is no NCS offered to evaluate the gluteal nerves. However,
obtaining electrodiagnostic abnormalities in NEMG testing of the gluteal
muscles can be beneficial in identifying gluteal neuropathies.17

**Distal Symmetric Polyneuropathy (DSP)**

****

Dupuis et al30 performed a retrospective chart review for 105 patients
referred to an electromyography laboratory for neuropathy, polyneuropathy or
lower extremity sensory changes with clinical histories of lower extremity
numbness, tingling, or pain, and no mention of unilateral or asymmetric
symptoms. The goal of the study was to evaluate the symmetry between the right
and the left lower extremity NCS in a cohort of patients with symptoms of DSP.

Of the 105 patient charts reviewed, 53 patients had bilateral sural sensory,
peroneal motor and tibial motor studies performed. Patient diagnoses included
neuropathy (76), normal or indeterminate (19), mononeuropathy (4) and
radiculopathy (6).

Existing consensus criteria for the diagnosis of DSP are an abnormality ( _>_
99th or _<_ 1st percentile) of any element of nerve conduction in two separate
nerves, one of which must be the sural nerve.

Considerable agreement was noted between abnormalities in individual nerve
parameters of the left and right lower extremities for all 105 patients,
particularly in the sural nerve. There was also considerable agreement
regarding whether the left and right lower extremities met the
electrodiagnostic criteria for DSP (k = 0.77) for the 53 patients with
bilateral sural, peroneal, and tibial studies. The authors concluded that this
study has shown that patients with symmetric neuropathy symptoms have a high
degree of agreement in NCS parameters between sides; therefore, bilateral
lower extremity NCS may have limited benefit in the assessment of suspected
DSP.30

**Cervical Radiculopathy (CR)**

Pawar et al31 performed a cross-sectional study to assess the diagnostic value
of different motor and sensory nerve conduction study parameters in 100
patients aged 40 years and above clinically diagnosed with CR. Typical
modalities to diagnose CR include clinical examination, radiological imaging
and electrophysiologic assessment. Usually imaging with a computed tomography
(CT) myelogram or magnetic resonance imaging (MRI) scan can detect a
structural lesion entrapping the nerve roots; however, radiculopathy and
polyradiculopathy can occur without a radiologically detectable structural
lesion. Frequently, the patient's history and physical assessment are
insufficient to differentiate CR from other neurologic sources of neck and arm
pain. In these situations, EDX studies are generally performed.

Exclusion criteria included patients with diabetes mellitus, clinical or
electrophysiological confirmation of polyneuropathy, duration of symptoms less
than three weeks or spinal surgery within the past 15 years. An MRI was
performed on study participants. The study concluded that among motor nerve
conduction parameters compound muscle action potential is more sensitive as
compared to distal motor latency and conduction velocity and sensory nerve
conduction parameters are less sensitive in diagnosing CR. The study showed
that NCSs are a useful supportive diagnostic tool for suspected CR.31

**Brachial Plexopathies and Lumbosacral Plexopathies**

Rubin4 performed a review of the literature regarding the brachial and
lumbosacral plexus, including the clinical characteristics, EDX approaches,
and appraisal and treatment of brachial and lumbosacral plexopathies. EDX
testing using a combination of NCS and NEMG is an important and vital element
of the assessment of brachial plexopathies (e.g., neuralgic amyotrophy,
thoracic outlet syndrome). EDX studies assist to: a) verify localization to
the brachial plexus while eliminating (or recognizing) radiculopathies or
mononeuropathies; b) detect the segment(s) of the plexus implicated; c)
describe the pathophysiology of nerve injury (e.g., axonal or demyelinating);
d) establish the degree of axon loss; and e) evaluate for evidence of
reinnervation or recovery of the nerves. Generally, EDX studies do not
establish the etiology of the plexopathy, but on occasion certain findings may
point towards a potential cause. In assessing a brachial plexopathy, both NCS
and NEMG give these types of information.

The objectives of conducting EDX studies in lumbosacral plexopathies (e.g.,
diabetic and non-diabetic lumbosacral radiculoplexus neuropathy) are similar
to those for brachial plexopathies and involve assisting to localize the
disorder to the lumbosacral plexus, rule-out more common lumbosacral
radiculopathies, and characterize the pathophysiology and severity of nerve
injury. Although there are fewer NCSs that can be conducted to assess the
lumbosacral plexus contrasted to the brachial plexus, the same EDX concepts
apply; abnormal sensory NCS and the absence of NEMG findings in the
lumbosacral paraspinals are supportive of a plexopathy.4

**Lumbosacral Radiculopathy**

Cho et al32 provides an evidence-based practice guideline developed from a
systematic review of the literature performed by the Lumbosacral Radiculopathy
Task Force as charged by the AANEM to assess the efficacy of EDX studies in
the diagnosis of lumbosacral radiculopathies. Evidence-based literature
indicates that the diagnosis of lumbosacral radiculopathy is founded on
clinical history and physical examination, imaging studies, and EDX studies.
EDX studies are particularly beneficial in situations with negative imaging
results or atypical clinical appearances while in circumstances with abnormal
imaging results, EDX testing functions in a complementary diagnostic role.

Conclusions of the study indicate: 1) In cases with suspected lumbosacral
radiculopathy, the following EDX studies may assist in developing the clinical
diagnosis: a) peripheral limb NEMG. b) paraspinal mapping (PM) with NEMG in
lumbar radiculopathy. c) H-reflex in S1 radiculopathy. 2) Evidence-based
literature implies a low sensitivity of peroneal and posterior tibial F-waves.
3) There is insufficient evidence to draw clear conclusions for the efficacy
of the following EDX studies: a) dermatomal/segmental SEP of the L5 or S1
dermatomes. b) PM with NEMG in sacral radiculopathy. c) motor evoked potential
(MEP) with root stimulation in formulating an independent diagnosis of
lumbosacral radiculopathy.32

**Lumbar Central Spinal Stenosis (LCSS)**

****

Chang and Park33 performed a retrospective chart review to examine the results
of NCSs and NEMG in 32 patients (average age 66.9 _+_ 7.4 years) with moderate
and severe LCSS and contrast findings of EDX tests in 15 patients (average age
65.2 _+_ 8.0 years) without LCSS (control group). The results showed that
patients with moderate or severe LCSS exhibited substantially lower distal
amplitudes of the compound motor action potential of both peroneal and tibial
nerves in comparison with the control group. The NEMG results showed that
positive sharp waves and fibrillation potentials were exclusively discerned in
patients with severe LCSS group (28.6%). The authors concluded that the
results of this study may be beneficial to diagnose radiculopathy as a result
of LCSS and to distinguish it from other peripheral nerve pathologies.33

**Vocal Cord Paralysis**

Munin et al38 performed a systematic review of the literature using the
American Academy of Neurology (AAN) criteria for rating of diagnostic
accuracy. This study was conducted to develop a consensus statement for using
laryngeal electromyography for the diagnosis and treatment of vocal cord
paralysis.

Recurrent laryngeal neuropathy (RLN) is a peripheral nerve lesion resulting in
vocal fold paralysis. Laryngeal electromyography (LEMG) is used to assess
neuromuscular function following laryngeal nerve injury to assist in decision
making about diagnosis, prognosis, and subsequent rehabilitative procedures.
The severity of nerve injury (e.g., conduction block, axonal loss, or a
combination of both) will affect the patient's recovery from RLN.

The results of the study show that LEMG is important in the clinical
management of a patient with vocal fold paralysis as the LEMG modified
clinical management about 48% of the time by changing the initial diagnosis
from RLN. Cricoarytenoid fixation and superior laryngeal neuropathy were the
most frequent diagnoses discerned when the pretest impression was RLN.38

**NMJ Disorders**

Neuromuscular junction testing, also known as repetitive nerve stimulation, is
an electrodiagnostic test that is used to diagnose NMJ disorders such as
myasthenia gravis and Lambert-Eaton myasthenic syndrome.27,34-35 The test
involves recording muscle responses to a series of nerve stimuli and may be
used in association with NCSs of the same nerves. At least one motor and one
sensory nerve conduction study should be performed in a clinically involved
limb, preferably in the distribution of a nerve studied with repetitive
stimulation or SFEMG. At least one distal and one proximal muscle should be
studied by a NEMG examination to exclude a neuropathy or myopathy that can be
associated with abnormal repetitive stimulation studies or SFEMG. At least one
of the muscles should be clinically involved and both muscles should be in
clinically involved limbs.1 Evidence-based guidelines have shown that SFEMG
may be used to assist in diagnosis and has shown positive in over 90% of
patients with ocular myasthenia.45

**Myopathies**

Chiodo24 provides a review of the literature concerning acquired
myopathies/dystrophies such as inflammatory myopathy and myositis (e.g.,
polymyositis, dermatomyositis, inclusion body myositis); congenital and
hereditary dystrophic and nondystrophic myopathies, including myotonic
muscular dystrophy; acquired myopathies (e.g., drug induced myopathy
associated with statins, thyroid related) and metabolic myopathies (e.g.,
McArdle disease).

Evidence-based literature indicates that NEMG is beneficial in recognizing the
presence of a myopathy by assessing motor units and their recruitment as well
as detecting possible muscle necrosis and inflammation as implied by the
presence of abnormal spontaneous activity. Electrodiagnosis is also valuable
in ruling out other disorders that may mimic a myopathy by assessing the
pattern of connection and by guiding the selection of location for a muscle
biopsy. It may also be beneficial in assessing response to treatment.24

NCS results are usually normal in myopathies though low compound muscle action
potential amplitudes may exist if the myopathy is severe and/or affects distal
musculature since distal muscles are generally utilized in NCSs. Sensory
responses are typically normal, except in disorders that cause both a myopathy
and neuropathy, such as critical illness neuromyopathy. Usually, at least one
motor and one sensory NCS is conducted in the arm and in the leg, and the test
expanded, contingent on those results. NEMG and/or NCS also permits
differentiation between muscle disease and defects of neuromuscular
transmission (both pre- and postsynaptic disorders).24

**Myotonic Dystrophy**

Burakgazi25 conducted a retrospective chart review for twelve patients with
adult-onset myotonic dystrophy who were previously diagnosed with diabetes
mellitus (DM)-type 1 and had EDX tests performed (average age 53.3 _+_ 15.2
years). The goal of the study was to portray the common EDX results in DM
patients and to evaluate the EDX sensitivity of muscles in the diagnosis of
DM.

The NCS demonstrated that more than half of the patients had normal sensory
and motor NCS results. In 11 of 12 patients, sensory NCSs were within normal
limits. Only one patient displayed abnormal sensory responses. The most
frequent abnormal NCS results were diminished amplitude of motor nerves with
normal latency and normal conduction velocity possibly due to muscle wasting
or motor axonal damage. The NEMG analysis proved more sensitive in detecting
myotonic discharges in distal muscles of the extremities than in proximal
muscles of the extremities. The author concluded that the NEMG study is
essential in the diagnosis of myotonic disorders, especially in clinically
elusive situations.25

**Anal or Urethral Sphincter Disorders**

Wald et al39 provides updated evidence-based clinical guidelines from the
American College of Gastroenterology (ACG) for management of benign anorectal
disorders. The guidelines include recommendations for defecatory disorders
(DDs) and fecal incontinence (FI). A diagnosis of DD requires both symptoms of
constipation and anorectal tests indicative of impaired rectal evacuation. A
digital rectal examination (DRE) is recommended as part of the assessment to
identify structural abnormalities (i.e., anal fissures, hemorrhoids, fecal
impaction, descending perineum syndrome, or anorectal cancer) and evaluate
anal sphincter function. Anorectal tests are needed as symptoms alone do not
discriminate between DD and other causes of constipation. The diagnostic tests
evaluate rectal sensation and anorectal pressures (manometry), rectal balloon
expulsion (BET), external anal sphincter and pelvic floor muscle activity
(with electromyography [EMG]), or rectal evacuation (barium or MRI
defecography). These diagnostic tests have strengths and limitations, and
there is no single gold standard. The recommendations for diagnostic
assessment for defecatory disorders indicate that a diagnosis of DD be
confirmed by at least two abnormal tests (i.e., anorectal manometry [ARM] and
balloon expulsion).39

The recommendations for FI include performing a physical examination to rule-
out diseases to which FI is secondary, performing an anorectal examination (to
identify rectal masses, gauge anal sphincter tone and pelvic floor motion at
rest, during voluntary contraction of the anal sphincter and pelvic floor
muscles, and during simulated defecation). A DRE should be done before
referral for ARM. The recommendations for diagnostic testing for FI include
ARM, BET and rectal sensation in patients who fail conservative treatment.
Pelvic floor and anal canal imaging and anal EMG should be considered for
patients with reduced anal pressures who have failed conservative therapy,
particularly if surgery is being considered.39

Winters et al40 provides evidence-based guidelines from the American
Urological Association (AUA) and the Society of Urodynamics, Female Pelvic
Medicine and Urogenital Reconstruction (SUFU) for Adult Urodynamics. This
guideline addresses the use of urodynamic tests for diagnosis, prognosis,
guidance of clinical management decisions, and improvement of patient outcomes
in patients with various urologic conditions. The authors noted the current
literature is deficient in Level-1 evidence, which could elucidate the precise
indications for urodynamic testing. Guideline statements for stress urinary
incontinence (SUI)/prolapse include the following: A) Clinicians may perform
multi-channel urodynamics in patients with both symptoms and physical findings
of stress incontinence who are contemplating invasive, potentially morbid or
irreversible treatments. Urodynamic studies (UDS) are not completely necessary
as a component of the preoperative evaluation in uncomplicated patients. B)
Multi-channel urodynamics can assess for the presence of detrusor dysfunction
in women with SUI with high grade pelvic organ prolapse as some women with
high grade pelvic organ prolapse may have an elevated post void residual or be
in urinary retention. Guideline statements for neurogenic bladder (NGB)
include the following: Clinicians should conduct EMG in combination with a
cystometrogram, with or without pressure flow studies, in patients with a
relevant neurologic disease at risk for a neurogenic bladder, or in patients
with other neurologic diseases and an elevated post void residual or in
patients with urinary symptoms.40

Kobashi et al43 provides evidence-based guidelines from the AUA and the SUFU
for the surgical treatment of female SUI. Guideline statements regarding UDS
include the following: A) Clinicians may omit urodynamic testing for the index
patient desiring treatment when SUI is clearly established. B) Clinicians may
perform urodynamic testing in non-index patients (Expert Opinion). The authors
also note that all surgical interventions (e.g., midurethral slings [MUS],
pubovaginal slings [PVS], colposuspension) to treat SUI have possible adverse
outcomes, such as continued incontinence, voiding dysfunction, urinary
retention, pain, and dyspareunia.

Ginsberg et al41 provides evidence-based guidelines from the AUA and the SUFU
for adult neurogenic lower urinary tract dysfunction (NLUTD). The guideline
statements regarding UDS include the following: A) For patients with low-risk
NLUTD, at initial assessment, the clinician should not routinely obtain upper
tract imaging, renal function evaluation, or multichannel urodynamics. B) For
patients with unknown-risk NLUTD, at initial assessment, the clinician should
obtain upper tract imaging, renal function assessment, and multichannel
urodynamics. C) For patients with low-risk NLUTD and stable urinary signs and
symptoms, the clinician should not obtain surveillance upper tract imaging,
renal function assessment, or multichannel urodynamics. D) For patients with
high-risk NLUTD and stable urinary signs and symptoms, the clinician should
assess the patient with an annual focused history, physical examination and
symptom evaluation; an annual renal function evaluation; an annual upper tract
imaging; and multichannel UDSs, with or without fluoroscopy, which may be
repeated when clinically indicated. E) For patients with moderate- or high-
risk NLUTD who encounter a change in signs and symptoms, new complications
(e.g., autonomic dysreflexia, urinary tract infections [UTIs], stones), or
upper tract or renal function deterioration, the clinician may perform
multichannel urodynamics. F) For NLUTD patients with recurrent UTIs and an
unremarkable assessment of the upper and lower urinary tract, clinicians may
perform urodynamic evaluation. G) For NLUTD patients with impaired storage
parameters and/or voiding that put their upper tracts at risk, clinicians
should repeat UDS at an appropriate interval following treatment. H) For
follow-up and post treatment, clinicians may conduct urodynamics following
sphincterotomy to evaluate outcome.41

Ginsberg et al42 provides evidence-based guidelines from the AUA and the SUFU
for treatment and follow-up of adult NLUTD. This guideline provides
recommendations for the appropriate assessment, diagnosis, and risk
stratification of adult patients with NLUTD and the non-surgical and surgical
treatment options available. Guideline statements concerning UDS include the
following: A) Evaluation of bladder storage parameters with UDS are
recommended to be conducted prior to any SUI procedure in patients with
relevant NLUTD where bladder compliance may be worsened by an outlet
procedure, resulting in elevated storage pressures and risk to the upper
urinary tracts. B) Evaluation of bladder storage parameters with UDS should be
conducted prior to any artificial urinary sphincter (AUS) placement in
patients with relevant NLUTD where bladder compliance may be worsened by an
outlet procedure, resulting in elevated storage pressures and risk to the
upper urinary tracts. C) Evaluation of bladder storage parameters with UDS
should be conducted in patients with relevant NLUTD where bladder compliance
may be worsened by an outlet procedure such as bladder neck closure (BNC),
resulting in elevated storage pressures and risk to the upper urinary tracts.
D) Urodynamic studies should be repeated at an appropriate interval following
treatment in NLUTD patients with impaired storage parameters and/or voiding
that place their upper tracts at risk. E) In NLUTD patients with impaired
storage parameters that place their upper tracts at risk and are refractory to
therapy, clinicians should offer additional treatment. Stepwise treatment
based on invasiveness is reasonable, providing repeated UDS are performed to
evaluate efficacy at appropriate intervals. F) UDS is recommended following
sphincterotomy to evaluate outcome. NLUTD patients may undergo non-surgical
and surgical treatment options contingent on their level of risk, symptoms,
and urodynamic findings. Proper follow-up, primarily based on their risk
stratification, must be maintained after treatment.42

Sandhu et al44 provides evidence-based guidelines from the AUA and the SUFU
for incontinence after prostate treatment (IPT). Guideline statements
regarding UDS include the following: A) Clinicians may conduct urodynamic
testing in a patient prior to surgical intervention for SUI in situations
where it may facilitate diagnosis or counseling. B) Clinicians should assess
patients with incontinence after prostate treatment with history, physical
exam, and appropriate diagnostic modalities to categorize type and severity of
incontinence and degree of bother. Confirmation of SUI can frequently be
established by history or physical exam alone; however there are times when a
clinician may choose advanced testing such as UDS.

**Number of Services**

The table below summarizes the recommendations of the AANEM1 regarding the
reasonable maximum number of studies per diagnostic category necessary for a
physician to arrive at a diagnosis for 90% of patients with that final
diagnosis.  
 **  
AANEM Recommended Number of Services Per Date of Service**

**Indication**

|

**NEMG # of Tests**

|

**Motor NCS with or without F-wave**

|

**Sensory NCS**

|

**H-Reflex**

|

**  
NMJ Testing (Repetitive Stimulation)**  
  
---|---|---|---|---|---  
  
Carpal Tunnel (unilateral)

|

1

|

3

|

4

|   |  
  
Carpal Tunnel (bilateral)

|

2

|

4

|

6

|   |  
  
Radiculopathy

|

2

|

3

|

2

|

2

|  
  
Mononeuropathy

|

1

|

3

|

3

|

2

|  
  
Polyneuropathy/Mononeuropathy Multiplex

|

3

|

4

|

4

|

2

|  
  
Myopathy

|

2

|

2

|

2

|   |

2  
  
Motor Neuronopathy (e.g., ALS)

|

4

|

4

|

2

|   |

2  
  
Plexopathy

|

2

|

4

|

6

|

2

|  
  
Neuromuscular Junction (NMJ)

|

2

|

2

|

2

|   |

3  
  
Tarsal Tunnel Syndrome (unilateral)

|

1

|

4

|

4

|   |  
  
Tarsal Tunnel Syndrome (bilateral)

|

2

|

5

|

6

|   |  
  
Weakness, Fatigue, Cramps or Twitching (focal)

|

2

|

3

|

4

|   |

2  
  
Weakness, Fatigue, Cramps or Twitching (general)

|

4

|

4

|

4

|   |

2  
  
Pain, Numbness, or Tingling (unilateral)

|

1

|

3

|

4

|

2

|  
  
Pain, Numbness, or Tingling (bilateral)

|

2

|

4

|

6

|

2

|  
  
_  
CTS_ : For suspected CTS, bilateral median motor and sensory NCSs are
frequently indicated. The studies in the contralateral asymptomatic limb
function as controls in cases where values are borderline and may determine
the presence of bilateral CTS, which is a common finding. Two to four
additional sensory or mixed NCSs can be contrasted to the median sensory NCSs
to enhance the diagnostic sensitivity of the testing. The additional sensory
NCSs and an additional motor NCS (usually ulnar) are indicated to rule-out a
generalized neuropathy or multiple mononeuropathies.1

If two sensitive sensory NCSs are conducted at the beginning, additional
sensory testing on the same limb is seldom needed. For suspected bilateral
CTS, bilateral median motor and sensory NCSs are indicated. Up to two
additional motor and two additional sensory NCSs are frequently indicated. The
extent of the NEMG assessment depends on the findings of the NCSs and the
differential diagnosis considered in the individual patient.1

Further testing may be indicated in patients with a differential diagnosis
that involves peripheral neuropathy, cervical radiculopathy, brachial
plexopathy, or more proximal median neuropathy.1 Additional tests may be
considered upon redetermination. In such circumstances, the rationale for the
additional tests should be included in the medical record.

_Radiculopathy_ : A minimal assessment for radiculopathy includes one motor
and one sensory NCS and a NEMG assessment of the involved limb. However, the
EDX testing can include up to three motor NCSs (in cases of an abnormal motor
NCS, the same nerve in the opposite limb and another motor nerve in the
ipsilateral limb can be studied) and two sensory NCSs. Bilateral tests are
frequently needed to rule out a central disc herniation with bilateral
radiculopathies or spinal stenosis or to differentiate between radiculopathy
and plexopathy, polyneuropathy, or mononeuropathy. H-reflexes and F-waves can
provide complementary information that is beneficial in the assessment of
suspected radiculopathy and can add to the certainty of EDX information
advocating a diagnosis of root dysfunction.1

Radiculopathies cannot be diagnosed by NCS alone; NEMG must be performed to
confirm a radiculopathy. Therefore, these studies should be performed together
by one physician/qualified health care practitioner supervising and/or
performing all aspects of the study.1

_Polyneuropathy/Mononeuropathy Multiplex_ : To characterize the nature of the
polyneuropathy (axonal or demyelinating, diffuse or multifocal) and to rule-
out polyradiculopathy, plexopathy, neuronopathy, or multiple mononeuropathies,
it may be necessary to test four motor and four sensory nerves, consisting of
two motor and two sensory NCSs in one leg, one motor and one sensory NCS in
the opposite leg, and one motor and one sensory NCS in one arm. H-reflex
studies and F-wave studies from two nerves may give additional diagnostic
information. At least two limbs should be studied by a NEMG examination.
Studies of related paraspinal muscles are indicated to rule-out some disorders
such as polyradiculopathy.1

_Myopathy_ : To diagnose a myopathy, a NEMG study of two limbs is indicated.
To help rule out other disorders such as polyneuropathy or neuronopathy, two
motor and two sensory NCSs are indicated. Two repetitive motor nerve
stimulation studies may be conducted to rule-out a disorder of neuromuscular
transmission.1

_Motor Neuronopathy_ : To verify the diagnosis of motor neuronopathy (for
example, ALS or Lou Gehrig's disease) and to rule-out other disorders in the
differential diagnosis, such as multifocal motor neuropathy or polyneuropathy,
up to four motor nerves and two sensory nerves may be studied.1

The NEMG assessment of up to four extremities (or three limbs and facial or
tongue muscles) is frequently needed to document widespread denervation and to
rule out a myopathy. One repetitive motor nerve stimulation test may be
indicated to rule-out a disorder affecting neuromuscular transmission.1

_Plexopathy_ : To characterize a brachial plexopathy and to distinguish it
from cervical radiculopathy and mononeuropathies, it is frequently necessary
to assess all major sensory and motor nerves that can be easily evaluated in
both upper extremities (radial, median, ulnar, and medial and lateral
antebrachial cutaneous sensory; radial, median, ulnar, and possibly axillary
and musculocutaneous motor) and to conduct a NEMG study in both upper
extremities. To characterize the lumbosacral plexopathy and to distinguish it
from lumbar radiculopathy and mononeuropathies, it is frequently necessary to
assess all major sensory and motor nerves that can be easily evaluated in both
lower extremities (superficial peroneal [fibular] and sural sensory; peroneal
[fibular] and posterior tibial motor) and to conduct a NEMG study in both
lower extremities. F-wave studies in the motor nerves and soleus H-reflexes
also offer beneficial information.1

NMJ: To reveal and characterize abnormal neuromuscular transmission,
repetitive nerve stimulation studies should be conducted in up to three nerves
and SFEMG in up to two muscles. If any of these are abnormal, up to two motor
and two sensory NCSs may be conducted to rule out neuropathies that can be
correlated with abnormal neuromuscular transmission. At least one motor and
one sensory NCS should be conducted in a clinically involved limb, preferably
in the distribution of a nerve studied with repetitive stimulation or SFEMG.
At least one distal and one proximal muscle should be tested by a NEMG
examination to rule-out a neuropathy or myopathy that can be associated with
abnormal repetitive stimulation studies or SFEMG. At least one of the muscles
should be clinically involved and both muscles should be in clinically
involved limbs.1

_Frequency of Electrodiagnostic Testing in a Given Patient_ : The frequency
for repeating EDX studies in a given patient by a given EDX provider for a
given diagnosis per year can be reasonably limited. The following numbers of
studies per 12-month period per diagnosis per physician are suitable: 1) Two
studies for carpal tunnel-unilateral, carpal tunnel-bilateral, radiculopathy,
mononeuropathy, polyneuropathy, myopathy, and NMJ disorders. 2) Three studies
for motor neuronopathy and plexopathy. These limits should not apply if the
patient requires assessment by more than one EDX provider (i.e., a second
opinion or an expert opinion at a tertiary care center) in a given year or if
the patient requires evaluation for a second diagnosis in a given year.1

Repeat EDX studies are rare and should not be necessary in a 12-month period
in 80% of all cases. In such circumstances, the rationale for the repeat study
should be included in the medical record. Comparison with the previous study
findings should be documented.1

**Procedures considered Experimental, Investigational, or Unproven**

EDX testing with automated, noninvasive nerve conduction testing devices is
considered investigational and not medically reasonable and necessary for all
indications, including as an alternative method of performing NCSs.3

Screening testing for polyneuropathy of diabetes in patients without clinical
deficits is not indicated. Testing for the sole purpose of monitoring disease
intensity or treatment efficacy in this condition is not indicated.3,20

Psychophysical measurements (electrical, vibratory or thermal perceptions),
even though they may involve delivery of a stimulus, are not considered
medically reasonable and necessary.3

Examination using portable hand-held devices, which are incapable of real-time
waveform display and analysis, will be included in the evaluation and
management (E/M) service.3

NEMG for the following situations is not considered medically reasonable and
necessary: 1) Exclusive study of intrinsic foot muscles in the diagnosis of
proximal lesions; 2) Definitive diagnosis based on paraspinal EMG in areas
with scar from past surgeries (e.g., previous laminectomies); 3) Performing
NEMG testing just after trauma occurs, before NEMG abnormalities would have
reasonable time to develop; 4) SEMG and macro-EMGs; 5) Multiple uses of NEMG
in the same patient at the same location of the same limb for the purpose of
optimizing botulinum toxin injections.3

Based on evidence-based literature, the Professional Practice Committee (PPC)
of the AANEM as part of the Choosing Wisely Initiative60 recommends that **the
following procedures not be performed** : 1) NEMG for isolated neck or back
pain after a motor vehicle accident. NEMG for neck pain without arm pain, arm
tingling, arm weakness, or arm numbness does not improve outcomes. The same is
true of NEMG for back pain without lower limb pain, lower limb tingling, lower
limb weakness, or lower limb numbness. 2) Dermatomal SEPs for a pinched nerve
in the neck or back, as they are an unproven diagnostic procedure. Though
methods such as NEMG and NCSs can be useful to diagnose pinched nerve in the
neck (cervical radiculopathy) or back (lumbar radiculopathy), dermatomal SEP
is of unproven worth for this purpose. There are several causes of neck,
shoulder, and upper limb pain besides cervical radiculopathy. There are also
several causes of back, hip, thigh, and lower limb pain other than lumbar
radiculopathy. 3) NCSs without a NEMG for a pinched nerve in the neck or back.
For diagnosis of a pinched nerve in the neck or back, NCSs alone cannot make
the diagnosis. NEMG is essential to detect and characterize the disease
process. 4) NCSs or NEMG for muscle pain without the presence of other
abnormalities on examination or laboratory testing. Muscle pain or myalgias
are widespread. The probability of discovering a muscle disease in an
individual with muscle pain who has a normal neurologic exam and laboratory
tests is quite low.

**Dystonia**

Albanese et al65 provides the revised European Federation of Neurological
Societies (NFNS) scientific task force committee guidelines on diagnosis and
treatment of primary dystonias. This evidence-based guideline indicates
neurophysiological tests are not normally recommended for the diagnosis or
classification of dystonia. Though multiple simultaneous NEMG recordings from
different muscles may add to the clinical assessment by displaying
characteristic features of dystonia.65

**Overactive Bladder**

Gormley et al66 provides evidence-based guidelines from the AUA and the SUFU
for the diagnosis and treatment of overactive bladder (OAB) (non-neurogenic)
in adults. Guideline statements regarding UDS include the following: A)
Urodynamics, cystoscopy and diagnostic renal and bladder ultrasound should not
be utilized in the initial workup of the uncomplicated patient. For
complicated patients or refractory patients who have failed multiple OAB
treatments, the option of additional diagnostic tests depends on patient
history and presentation and clinician judgment. B) In select cases, the
clinician may elect to obtain further information with voiding diaries or
symptom questionnaires, or may do further testing such as urodynamics to rule
out other bladder pathologies or urethral dysfunction.

**QST**

Georgopoulos et al54 performed a systematic review of the literature regarding
the evidence for the capability of QST to predict pain, disability, and
negative affect. Of the 37 studies included in the review (n = 3860
participants), 32 were prospective cohort studies and five were randomized
controlled trials (RCTs). Pain was an outcome in 30 studies, disability in 11
and negative affect in three. Meta-analysis showed that baseline QST predicted
musculoskeletal pain and disability. Baseline modalities quantifying central
mechanisms such as temporal summation (TS) and conditioned pain modulation
(CPM) were correlated with follow-up pain, whereas baseline mechanical
threshold modalities were predictive of follow-up disability. The authors
concluded that QST indicators of pain hypersensitivity might aid to develop
targeted interventions aiming to enhance outcomes across a range of
musculoskeletal conditions. However, this needs to be validated in further
studies.54

Shy et al55 performed a systemic review of the literature to assess the
clinical utility, efficacy, and safety of QST on behalf of the Therapeutics
and Technology Assessment Subcommittee of the AAN. This review included 350
articles that employed computer operated threshold systems, manually operated
threshold systems, and electrical threshold devices. The use of normal values
and the degree of reproducibility between the same and different systems were
evaluated. Because of variances between systems, normal values from one system
cannot be transferred to others. Reproducibility of findings was also a
significant concern, and there is no consensus on how it should be defined.
There were no adequately powered class I studies found showing the
effectiveness of QST in assessing any particular disorder. A few class II and
III studies determined that QST is probably or possibly useful in identifying
small or large fiber sensory abnormalities in patients with diabetic
neuropathy, small fiber neuropathies, uremic neuropathies, and demyelinating
neuropathy. The authors concluded that QST is possibly a useful tool for
measuring sensory impairment for clinical and research studies. However, QST
findings should not be the only criteria utilized to diagnose pathology. QST
is not currently useful for the purpose of resolving medicolegal matters since
malingering and other nonorganic factors can influence the test outcomes.
Well-designed studies contrasting various QST devices and methodologies are
necessary and should include patients with abnormalities detected solely by
QST.55

Katz et al56 performed a systematic review of the literature to evaluate the
use of QST methods to detect hyperalgesia in chronic pain patients on long-
term opioids in clinical trials. Fourteen articles were involved in the
review: one RCT, one prospective controlled trial, three prospective
uncontrolled trials, and nine cross-sectional observation trials. Hyperalgesia
measurement paradigms utilized cold pain, heat pain, pressure pain, electrical
pain, ischemic pain, and injection pain. While none of the stimuli could
detect patients' hyperalgesia, heat pain sensitivity indicated some
encouraging findings. The authors concluded that none of the QST methods
reviewed met the criteria of a definitive standard for the measurement of
hyperalgesia. The authors indicate that further studies should be performed
that use improved study design.56

Marcuzzi et al57 performed a systematic literature review to evaluate the
prognostic value of QST measures in individuals with low back pain (LBP).
Studies were included if they were prospective longitudinal in design,
evaluated at least one QST measure in individuals with LBP, evaluated LBP
status at follow-up, and reported the correlation of QST data with LBP status
at follow-up. Statistical pooling of outcomes was unattainable due to
heterogeneity between studies. Of the 6,408 articles screened after duplicates
were removed, only three studies were included. None of these articles
described a substantial association between the QST measures evaluated and the
LBP outcome. Three areas at high risk of bias were recognized that possibly
compromise the validity of these findings. The authors concluded that because
of the lack of available studies and the methodological shortcomings detected,
it remains unknown whether QST measures are predictive of outcome in LBP.57

Wang et al67 performed a systematic review of the literature to assess the
diagnostic accuracy of monofilament tests for identifying diabetic peripheral
neuropathy. A total of 19 comparative studies met the inclusion criteria and
were part of the qualitative synthesis. Eight studies utilizing NCS as the
reference standard were chosen for the meta-analysis. The pooled sensitivity
and specificity of monofilament tests for identifying diabetic peripheral
neuropathy were 0.53 and 0.88, respectively. The pooled positive likelihood
ratio and negative likelihood ratio were 4.56 and 0.53, respectively. The
authors concluded that monofilament tests had limited sensitivity for
screening diabetic peripheral neuropathy. Based on currently available
evidence, the clinical utilization of monofilament tests in the assessment of
diabetic peripheral neuropathy cannot be supported.67

**SEMG**

The AANEM61 performed a systematic review of the literature regarding the use
of SEMG in the diagnosis and study of neuromuscular disorders. Evidence-based
literature indicates: 1) SEMG may be helpful to identify the presence of
neuromuscular disease. 2) The data are inadequate to establish the clinical
efficacy of SEMG for differentiating between neuropathic and myopathic
conditions or for identifying the more specific neuromuscular conditions of
post-poliomyelitis syndrome, pathologic fasciculations, acquired demyelinating
peripheral neuropathy, amyotrophic lateral sclerosis, myotonic dystrophy, and
hypokalemic periodic paralysis. 3) The data are inadequate to address the
question of disease severity detectable by SEMG. 4) The data are lacking to
contrast the diagnostic effectiveness of SEMG with the established
technologies of NEMG, NCS, and muscle ultrasonography. The authors concluded
that the literature shows no added clinical efficacy for SEMG above the
established NEMG as a diagnostic tool for detection and distinction of
myopathic from neuropathic neuromuscular disease.61

Wang et al62 conducted a systematic review and meta-analysis of the literature
to assess the significance of SEMG as a measure of trunk muscle activity in
patients with spinal cord injury (SCI). The review included eleven case-
control, cohort, and cross-sectional studies. The evidence revealed that trunk
muscle activities for the sitting condition were greater in individuals with
SCI than normal individuals. SEMG activity of trunk muscles for the sitting
condition and posterior transfer was greater in individuals with high level
(HL)-SCI contrasted to those with low level (LL)-SCI. Also, across studies,
the level of trunk muscle activity for various difficulty settings was
different for a given SCI group. The authors concluded that further research
is needed to assess the efficacy of SEMG studies for trunk muscles for
individuals with SCI.62 There is no evidence from this study that this
information will affect patient management.

Halford et al63 performed a prospective multicenter phase III study to assess
the performance and tolerability in the epilepsy monitoring unit (EMU) of an
investigational wearable SEMG monitoring system for the recognition of
generalized tonic-clonic seizures (GTCSs). Study participants included 199
patients with a history of GTCSs who were admitted to the EMU in eleven level
IV epilepsy centers for clinically indicated video-electroencephalographic
monitoring and who received SEMG monitoring with a wearable device that was
worn on the arm over the biceps muscle. All recorded SEMG data were processed
at a central site utilizing a previously created detection algorithm. Detected
GTCSs were contrasted to events confirmed by a majority of three expert
reviewers. For all patients, the detection algorithm detected 35 of 46 (76%,
95% confidence interval [CI] = 0.61 - 0.87) of the GTCSs, with a positive
predictive value (PPV) of 0.03 and an average false alarm rate (FAR) of 2.52
per 24 hours. For data recorded while the device was positioned over the
midline of the biceps muscle, the system detected 29 of 29 GTCSs (100%, 95% CI
= 0.88 - 1.00), with a detection delay averaging 7.70 s, a PPV of 6.2%, and a
mean FAR of 1.44 per 24 hours. Mild to moderate adverse events were reported
in 28% (55 of 199) of patients and led to study withdrawal in 9% (17 of 199).
These adverse events generally involved skin irritation produced by the
electrode patch that resolved without treatment. No serious adverse events
were reported. The authors concluded that recognition of GTCSs using a SEMG
monitoring device on the biceps is possible. However, improvements in the
device are necessary to reduce the number of false-positive detections.63

**Physiologic Recording of Movement Disorder Symptoms**

Heldman et al59 evaluated the reliability and responsiveness of a portable
kinematic system for quantifying Parkinson's disease (PD) motor deficits as
compared to clinical ratings. Eighteen PD patients with subthalamic nucleus
deep-brain stimulation (DBS) completed three tasks for assessing resting
tremor, postural tremor, and finger-tapping speed, amplitude, and rhythm while
wearing a wireless motion-sensor unit (KinesiaTM) on the more-affected index
finger. These tasks were repeated three times with DBS turned off and at each
of ten distinctive stimulation amplitudes chosen to yield small changes in
treatment response. Each task performance was video recorded for subsequent
clinician rating in blinded, randomized order. Test-retest reliability was
calculated as intraclass correlation (ICC), and sensitivity was calculated as
minimal detectable change (MDC) for each DBS amplitude. The ICCs for KinesiaTM
were substantially higher than those for clinician ratings of finger-tapping
speed, amplitude, and rhythm, but were not significantly different for
evaluations of resting or postural tremor. Likewise, KinesiaTM scores yielded a
lower MDC as contrasted with clinician scores across all finger-tapping sub-
scores but did not differ significantly for resting and postural tremor. The
authors concluded that the KinesiaTM portable kinematic system may offer
greater test-retest reliability and sensitivity to change than conventional
clinical ratings for measuring bradykinesia, hypokinesia, and dysrhythmia in
PD patients. However, the study did not substantiate the efficacy of such
findings in improving care and outcome of patients. Additional studies are
needed with robust evidence revealing consistent patient-relevant outcomes
with the use of physiologic recording of movement disorder symptoms.59

**Automated Point of Care Nerve Conduction Tests**

The results of preliminary trials for automatic or portable nerve conduction
monitoring systems are encouraging; however, the studies are predominantly
small case series contrasting portable nerve conduction monitoring systems
with conventional NCSs or clinical examination in the same patient.47-52
Additional studies are needed with robust evidence revealing consistent
patient-relevant outcomes with the use of point of care nerve conduction
tests.

Sharma et al53 conducted a study to evaluate a point-of-care nerve conduction
device (POCD) (NC-stat|DPNCheckTM) in the assessment of diabetes
polyneuropathy (DPN) and contrasted it with the LDIFLARE that utilizes a laser
Doppler imaging technique for early detection of small fiber dysfunction.
Study participants included 162 patients with DM and 80 healthy controls (HC).
Based on the 10-point Neuropathy Disability Score (NDS), DPN was categorized
into none (< 2), mild (3 - 5) moderate (6 - 7), and severe (8 - 10). The
correlations between POCD outcomes and the LDIFLARE within the NDS categories
were assessed utilizing regression analysis. In the HC and DM groups, the
sural nerve conduction velocity (SNCV) and the sensory nerve action potential
(SNAP) amplitude measured with the POCD correlated appreciably with the
LDIFLARE technique. Significance was also noted in all categories of DPN. The
receiver operating characteristic (ROC) curves within each category of DPN
indicated that the POCD was sensitive in the evaluation of DPN. The authors
concluded that the NC-stat|DPNCheckTM system seems to have considerable
potential for evaluating DPN in the clinical setting. According to the
authors, the NC-stat may be limited as it is dependent on the presence of an
accessible sural nerve that can be anatomically absent in up to 9% of healthy
individuals.53 Additional studies are needed with robust evidence revealing
consistent patient-relevant outcomes with the use of point of care nerve
conduction tests.

EDX studies are an extension of the clinical evaluation of patients with
conditions of the peripheral and/or central nervous system. EDX studies are
often vital in evaluating symptoms, arriving at a proper diagnosis, and in
following a disease process and its response to therapy in patients with
neuromuscular disorders.

Evidence-based guidelines and/or peer-reviewed literature indicate that NCSs
and NEMG are beneficial when they are conducted and interpreted at the same
time, on site, and in real time for the following conditions: **1)**
Plexopathy - including idiopathic, traumatic, inflammatory or infiltrative,
radiation-induced,1 brachial plexopathies (e.g., neuralgic amyotrophy,
thoracic outlet syndrome) and lumbosacral plexopathies (e.g., diabetic, non-
diabetic lumbosacral radiculoplexus neuropathy),4 **2)** Focal neuropathies
(e.g., entrapment neuropathies, or compressive lesions/syndromes such as
carpal tunnel syndrome,5-8 ulnar neuropathy,9-10 tarsal tunnel syndrome,11
femoral neuropathy, saphenous neuropathy, lateral femoral cutaneous
neuropathy, peroneal (fibular) neuropathy, tibial neuropathies, sciatic
neuropathy),1,12-18 **3)** Generalized neuropathies such as metabolic (e.g.,
diabetic, uremic), toxic, hereditary or immune-mediated,1,19-20 **4)** Motor
neuron disease (e.g., ALS or Lou Gehrig's disease),1,21-22 **5)** Myopathy -
including inflammatory myopathies such as polymyositis and dermatomyositis,
congenital myopathies,23 congenital and hereditary dystrophic and
nondystrophic myopathies, including myotonic muscular dystrophy, acquired
myopathies (drug induced myopathy associated with statins, thyroid related),
metabolic myopathies (e.g., McArdle disease),1,24 **6)** Myotonic disorders
(e.g., drug induced myotonia),25 **7)** Neuromuscular junction disorders
(e.g., myasthenia gravis, Lambert-Eaton myasthenic syndrome,
botulism),1,26-27,34-35 **8)** Polyneuropathies,1,28-30 **9)** Radiculopathy -
cervical,31 thoracic or lumbosacral,1,32-33 **10)** Spinal cord disorders31
(i.e., myelopathy), **11)** Symptom-based presentations such as "pain in
limb", weakness, cramping/twitching, disturbance of skin sensation or
"paresthesia" when appropriate pre-test evaluations are inconclusive, and the
clinical assessment unequivocally supports the need for the study,1 and
**12)** Traumatic nerve lesions, for diagnosis and prognosis.1

Evidence-based guidelines and/or peer-reviewed literature demonstrate support
for NMJ studies for the following conditions: **1)** Botulinum toxicity,1,3
**2)** Motor neuron disease (e.g., ALS or Lou Gehrig's disease),1 **3)**
Myopathy,1,34 **4)** Myasthenia gravis,27 and **5)** Myasthenic syndrome
(e.g., Lambert-Eaton myasthenic syndrome).1,3

Evidence-based guidelines and/or peer-reviewed literature lend support for
NCSs when performed **without** NEMG for the following situations: **1)**
Individuals treated with anticoagulants35-36 such as warfarin (Coumadin),
rivaroxaban (Xarelto), dabigatran (Pradaxa), apixaban (Eliquis), edoxaban
(Lixiana), clopidogrel (Plavix), ticagrelor (Brilinta), ticlopidine (Ticlid),
prasugrel (Effient), varapaxar (Zontivity), dipyridamole, cilostazol (Pletal),
**2)** Individuals with significant lymphedema in the affected extremity,36
**3)** Individuals being evaluated for carpal tunnel syndrome or tarsal tunnel
syndrome,3,11 and **4)** Guidance for botulinum toxin treatment injections
when it is difficult to isolate affected muscles1,37

Evidence-based guidelines and/or peer-reviewed literature indicate that NEMG
when conducted **without** NCSs is useful for the following situations: **1)**
Guidance for botulinum toxin treatment injections when it is difficult to
isolate affected muscles,1,37 **2)** Laryngeal neuropathy,38 **3)**
Constipation,39 **4)** Fecal incontinence,39 **5)** Lower urinary tract
symptoms,40-44 and **6)** Patients with risk factors for urinary
retention.40-44

Evidence-based guidelines recommend SFEMG for ocular myasthenia.45

The quality of evidence in the literature is insufficient to support the
following: **1)** EDX studies where the interpretation is delayed and not
completed at the time the study is performed.2,8,46 The NCS must be performed
and interpreted with the NEMG on site and in real time1-2 **2)** EDX studies
(NCS and NEMG) not performed by a physician or under direct supervision of a
physician in the office setting1 (Refer to the CMS IOM Pub 100-02, _Medicare
Benefit Policy Manual_ , Chapter 15, Section 80 Requirements for Diagnostic
X-Ray, Diagnostic Laboratory, and Other Diagnostic Tests) **3)** Non-invasive
EDX studies using portable hand-held devices or automated point of care nerve
conduction monitoring systems, which are incapable of real-time waveform
display and analysis3,47-53 **4)** Testing for polyneuropathy of diabetes in
patients without clinical deficits or for the sole purpose of monitoring
disease intensity or treatment efficacy3,20 **5)** QST (e.g., hot-cold, touch,
vibration)54-58 **6)** NCSs accomplished with discriminatory devices that use
fixed anatomic templates and computer-generated reports used as an adjunct to
physical examination routinely on all patients1 **7)** Physiologic recording
of movement disorder symptoms, including bradykinesia, dyskinesia, and tremor
using wearable devices with accelerometers or gyroscopes59 **8)** NCSs or NEMG
for muscle pain without the presence of other abnormalities on examination or
laboratory testing60 **9)** NEMG for the following situations: a) Definitive
diagnosis based on paraspinal NEMG in areas with scar from past surgeries
(e.g., previous laminectomies)3 b) SEMG3,61-63 c) Macro-EMG3, and d) NEMG for
isolated neck or back pain after a motor vehicle accident.60

Studies performed beyond the reasonable maximum number of studies recommended
in the CPT Codebook, Appendix J, Electrodiagnostic Medicine Listing of
Sensory, Motor, and Mixed Nerves. These recommendations are supported by the
AANEM.1 Additional studies may be considered upon redetermination.

Evidence-based guidelines indicate that repeat EDX assessment may be needed in
certain circumstances. The frequency for repeating EDX studies in a given
patient by a given EDX provider for a given diagnosis per year can be
reasonably limited. The following number of studies per 12-month period per
diagnosis per provider are suitable: 1) Two studies for carpal tunnel-
unilateral, carpal tunnel-bilateral, radiculopathy, mononeuropathy,
polyneuropathy, myopathy, and NMJ disorders. 2) Three studies for motor neuron
disease and plexopathy. These limits should not apply if the patient requires
assessment by more than one EDX provider (i.e., a second opinion or an expert
opinion at a tertiary care center) in a given year or if the patient requires
evaluation for a second diagnosis in a given year.1

Repeat EDX studies are rare and should not be necessary in a 12-month period
in 80% of all cases.1 Additional studies may be considered upon
redetermination. In such circumstances, the rationale for the repeat study
should be included in the medical record. Comparison with the previous study
findings should be documented.