Electromyography (EMG) is the study and recording of intrinsic electrical properties of skeletal muscles. This is carried out with a needle electrode. Results reflect not only on the integrity of the functioning connection between a nerve and its innervated muscle, but also on the integrity of a muscle itself.

Nerve conduction velocity (NCV) also called nerve conduction study (NCS) is the study of a nerve being stimulated electronically through the skin and underlying tissue to measure nerve conduction time. Results of NCV studies reflect on the integrity and function of the myelin sheath and the axon of the nerve.

EMG and NCV studies are commonly performed in conjunction with each other to confirm a clinical diagnosis of the peripheral nervous system disorders.

Neuromuscular junction testing (repetitive stimulation) involves recording muscle responses to a series of nerve stimuli applied at differing rates, both before and after exercise or transmission of high-frequency stimuli. Testing may be performed in addition to NCS of the same nerves and/or EMG. Testing is indicated for suspected diseases of the neuromuscular junction (generally associated with progressive motor fatigability) which include myopathy, focal neuropathy, Myasthenia gravis and Lambert Eaton Myasthenic syndrome. Another condition that testing may be indicated for, botulism, is associated with a decrease in the amount of acetylcholine released, and results in weakness.

EMG may be considered medically necessary for any ONE of the following conditions:
 

• Nerve compression syndromes, including carpal tunnel syndrome and other focal compressions; or
• Radiculopathy (cervical, lumbosacral); or
• Mono/polyneuropathy (metabolic, degenerative, hereditary); or
• Myopathy (including poly and dermatomyositis, myotonic, and congenital myopathies); or
• Plexopathy (idiopathic, trauma, infiltration); or
• Neuromuscular junction disorders (e.g., myasthenia gravis ); or
• Recurrent laryngeal neuropathy (RLN), (unilateral or bilateral vocal cord fold paralysis) that is greater than four (4) weeks but less than six (6) months in duration; or
• Precise muscle location for injections such as botulinum toxin, phenol, etc.

EMG for any other indication is considered not medically necessary.

NCV studies may be considered medically necessary for ANY of the following conditions:
 

• Compressive lesions (neuropathies); or
• Diagnosis or confirmation of suspected generalized and focal neuropathies/myopathies, (e.g., diabetic, uremic, metabolic, or immune); or
• Differential diagnosis of symptom-based complaints (e.g., pain in limb, weakness, disturbance in skin sensation or paresthesia) provided the clinical assessment supports the need for a study; or
• Motor neuron diseases; or
• Nerve root compression; or
• Neuromuscular junction disorders (e.g., myasthenia gravis, myasthenic syndrome); or 
• Plexopathies; or 
• Traumatic nerve lesions, for diagnosis and prognosis.

NCV is considered not medically necessary for any other indications. 

An H-reflex test can be paid separately from any EMG studies and NCV studies listed and should be limited to one unilateral or bilateral study per session per code.

An F-Wave is considered a form of nerve conduction testing. When reported independently, it should be processed according to the number of nerves studied.

Payment higher than the established allowance for an NCV study should not be made if a doctor reports that multiple methods (e.g., surface and needle electrodes) or multiple sites were used, or that an anatomical crossover existed (e.g., a median nerve is stimulated but the ulnar nerve is affected). None of these constitute a circumstance of such an unusual nature as to warrant additional payment.

Electrodiagnostic assessment consisting of EMG and NVC may be considered medically necessary as an adjunct to history, physical exam and imaging studies when the following criteria are met and when performed together and interpreted on the same day for ANY of the following conditions:
 

·         Generalized myopathy, including but not limited to ANY of the following:

o    Polymyositis; or

o    Dermatomyositis; or

o    Myotonic myopathy; or

o    Congenital myopathy; or

o    Muscular dystrophies; or

·         Plexopathies

o    Cervical; or

o    Brachial; or

o    Lumbosacral; or

·         Focal neuropathy, entrapment neuropathy, compressive lesion/syndrome, including but not limited to any of the following:

o    Carpel tunnel; or

o    Cubital tunnel syndrome; or

o    Tarsal tunnel syndrome; or

o    Ulnar nerve entrapment; or

o    Peroneal nerve compression; or

o    Thoracic outlet syndrome; or

o    Other peripheral nerve entrapments; or

·         Generalized neuropathy or confirmed diagnosis including but not limited to any ONE of the following:

o    Metabolic and nutritional (diabetic, uremic, amyloidosis, hypothyroidism, immune, vitamin B12  or thiamine deficiency); or

o    Toxic neuropathy (e.g. vincristine, amiodarone); or

o    Hereditary polyneuropathy (Charcot-Marie tooth Disease); or

o    Demyelinating polyneuropathies;

§  Guillain-Barre' syndrome (acute); or

§  Chronic idiopathic demyelinating polyneuropathy; or

o    Idiopathic peripheral neuropathy; or

o    When used as a diagnostic aid in the evaluation of signs/symptoms suggestive of diabetic or uremic neuropathy; or

o    Alcohol-related neuropathy; or

·         Traumatic peripheral nerve lesion; or

·         Nerve root, peripheral nerve, muscle, or neuromuscular junction involvement with symptom- based presentation and pre-test evaluations are inconclusive and clinical assessment supports the need for the study, such as for ANY of the following:

o    Muscle weakness; or

o    Muscle atrophy; or

o    Muscle fasciculation; or

o    Myokymia (involuntary twitching of the eyelid muscles); or

o    Myotonia; or

o    Loss of dexterity; or

o    Spasticity; or

o    Hyperreflexia; or

o    Sensory deficits; or

o    Diplopia; or 

o    Ptosis; or

o    Swallowing dysfunction; or

o    Dysarthria; or

o    Impaired bowel motility; or

·         Motor neuron disease

o    Amyotrophic lateral sclerosis; or

o    Progressive muscular atrophy; or

o    Progressive bulbar palsy; or

o    Pseudobulbar palsy; or

o    Primary lateral sclerosis; or

·         Spine disorder and BOTH of the following:

o    Appropriate imaging studies (e.g., CT scan, MRI, myelogram) confirming nerve root impingement; and any ONE of the following:

§  To differentiate radiculopathy from other neuropathies or non-neuropathic processes; or

§  To establish whether imaging findings are responsible for reported pain; or

§  To reconcile when pattern of pain, sensory impairment, or weakness does not match imaging findings; or

§  To document degree of axonal nerve damage in an individual with weakness.

A repeat electrodiagnostic assessment may be considered medically necessary when at least ONE of the following criteria have been met:
 

·         Development of new symptoms or signs suggesting a second diagnosis in a patient who has received an initial diagnosis; or

·         Interim progression of disease following an initial test that was inconclusive, such that a repeat test is likely to elicit additional findings; or

·         Unexpected change(s) in the course of disease or response to treatment, suggesting that the initial diagnosis may be incorrect and that reexamination is indicated.

Electrodiagnostic assessment consisting of EMG and NVC for any other indications is considered not medically necessary.

Repetitive Nerve Stimulation (RNS) in the diagnosis of a neuromuscular junction disease may be considered medically necessary for the following conditions:

• Myopathy; or
• Motor neuropathy (e.g., ALS); or
• Botulinum toxicity; or
• Myasthenia Gravis; or
• Lambert Eaton myasthenic syndrome; and
• The presence of ANY of the following symptoms:
  • Diplopia; or
  • Dysphagia; or
  • Fatigue/weakness that progresses with repetitive activity.

RNS for any other indication is considered not medically necessary.

Neuromuscular junction testing (repetitive stimulation) should be processed separately and should be limited to two repetitive stimulations per session.

The following tests are considered experimental/investigational and therefore, non-covered. Scientific evidence does not support the use of these tests.

• A “surface” EMG (SEMG) which includes a surface paraspinal EMG.
• Macro EMG.
• Automated non-invasive electro-diagnostic testing with a computerized hand-held device (e.g., NC-stat®) to stimulate and measure neuromuscular signals.
• Quantitative sensory testing (QST) which is the assessment of perceptual and/or physiological responses to pain. 

Recommended Maximum Number of Electrodiagnostic Studies for Specific Diagnosis