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Evoked Potential Studies

Policy Number: MP-395

Latest Review Date: November 2019

Category: Medical                                                                 

Policy Grade: Active Policy but no longer scheduled for regular literature reviews and updates.

 

 

POLICY:

Somatosensory evoked potentials (SEP, SSEP) or dermatosensory evoked potentials (DSEP) may be considered medically necessary for any of the following indications:

 

  • Unexplained myelopathy;

  • To localize the cause of a central nervous system deficit seen on exam, but not explained by lesions seen on CT or MRI;

  • To identify clinically silent brain lesions in multiple sclerosis (MS) suspects in order to establish the diagnosis, where MS is suspected due to presence of suggestive neurologic symptoms plus one or more other objective findings (brain plaque on MRI, clinical lesions by history and physical examination, and/or positive CSF as determined by oligoclonal bands detected by established methods such as isoelectric focusing, different from any such bands in serum, or by an increased IgG index);

  • To manage persons with spinocerebellar degeneration (e.g., Friedreich’s ataxia, olivopontocerebellar (OPC) degeneration);

  • To assess any decline which may warrant emergency surgery in an unconscious person with a spinal cord injury who shows specific structural damage to the somatosensory system and is a candidate for emergency spinal cord surgery;

  • To evaluate a person with suspected brain death.

 

Somatosensory evoked potentials (SEP, SSEP) or dermatosensory evoked potentials (DSEP)  are considered  not medically necessary and investigational for all other indications, including but not limited to:

  • SEP in conscious persons with severe spinal cord or head injuries, as the standard neurologic exam is the most direct way to evaluate any deficits;

  • SEP in the diagnosis or management of amyotrophic lateral sclerosis (ALS);

  • SEP in the diagnosis of cervical spondylitic myeloradiculopathy;

  • SEP in the diagnosis or management of acquired metabolic disorders (e.g., lead toxicity, B12 deficiency);

  • SEP in the diagnosis of thoracic outlet syndrome;

  • SEP for the diagnosis of carpal tunnel syndrome/ulnar nerve entrapment;

  • SEP for radiculopathies and peripheral nerve lesions where standard nerve conduction velocity studies are diagnostic.

 

Note:  Depending on the clinical condition being investigated, it may be medically necessary to test several nerves in one extremity and compare them with the opposite limb.

 

Documentation Requirements:  The physician’s SEP report should note which nerves were tested, latencies at various testing points, and an evaluation of whether the resulting values are normal or abnormal.

 

Visual evoked potentials (VEP) may be considered medically necessary for any of the following indications:

 

  • To identify persons at increased risk for developing clinically definite multiple sclerosis;

  • To diagnose or monitor multiple sclerosis (acute or chronic phases);

  • To localize the cause of a visual field defect, not explained by lesions seen on CT or MRI, metabolic disorders, or infectious diseases;

  • To evaluate signs and symptoms of visual loss in persons who are unable to communicate (e.g., unresponsive persons, etc.).

 

Visual evoked potentials (VEP) are considered not medically necessary and investigational for all other indications, including for routine screening of infants.

 

Automated visual evoked potentials (VEP) are considered not medically necessary and investigational.

 

Brain stem auditory evoked response (BAER), also known as brainstem auditory evoked potentials (BAEP) or auditory evoked potentials (AEP) may be considered medically necessary  for any of the following indications:

 

  • To diagnose suspected acoustic neuroma;

  • To assess recovery of brainstem function after a lesion compressing the brainstem has been surgically removed;

  • To localize the cause of a central nervous system deficit seen on exam, but not explained by CT or MRI;

  • To diagnose and monitor demyelinating and degenerative disease affecting the brain stem (e.g., central pontine myelinolysis, olivopontocerebellar (OPC) degeneration);

  • To evaluate infants and children who have suspected hearing loss that cannot be effectively measured or monitored through audiometry;

  • To screen infants and children under age 5 for hearing loss;

NOTE:  For purposes of neonatal screening, only limited auditory evoked potentials or limited evoked otoacoustic emissions may be considered medically necessary.  Neonates who fail this screening test are then referred for comprehensive auditory evoked response testing or comprehensive otoacoustic emissions.

  • To assess brain death or profound metabolic coma in selected cases where diagnosis or outcome is unclear from standard tests (e.g., EEG);

  • To diagnose post-meningitic deafness in children.

 

BAER is considered not medically necessary and investigational when:

  • as a test to identify persons at increased risk for developing clinically definite multiple sclerosis (CDMS).

 

Comprehensive auditory evoked response testing and comprehensive otoacoustic emissions are considered not medically necessary and investigational for neonatal screening.

 

Miscellaneous Indications:

The following studies and indications are considered not medically necessary and investigational:

 

  • AEP to determine gestational age or conceptual age in pre-term neonates;

  • Cognitive evoked potentials, also known as auditory or visual P300 or P3 cognitive evoked potentials, to diagnose cognitive dysfunction in persons with dementia (e.g., Alzheimer’s disease and Parkinson’s disease) or to identify the etiology of depression in persons with chronic demyelinating disease;

  • Event-related potentials for the diagnosis of attention deficit/hyperactivity disorder or post-traumatic stress disorder, or assessment of brain injury, or evaluation of comatose persons;

  • Gustatory evoked potentials for diagnosing taste disorders;

  • Motor evoked potentials, other than for intraoperative use with SSEP;

  • Cortical auditory evoked response (CAER) for the diagnosis of depression, attention deficit/hyperactivity disorder, autism, or any other indication;

  • Vestibular evoked myogenic potentials (VEMP).

 

DESCRIPTION OF PROCEDURE OR SERVICE:

Evoked potentials are the electrical signals generated by the nervous system in response to sensory stimuli. The sensory system involved and the sequence of activation of different neural structures determines the timing and location of these signals. Because of their low voltage, evoked potentials generally are not discernible without computer averaging to differentiate them from ongoing EEG activity and other sources of electrical noise. Typically, it is necessary to present the stimulus repeatedly, averaging the time-locked brain or spinal cord responses to a series of identical stimuli, while allowing unrelated noise to average out. In the clinical setting, evoked potential studies are an extension of the neurological exam. They help reveal the existence and often suggest the location of neurological lesions. Evoked potentials are most useful when they detect clinically silent abnormalities that might otherwise go unrecognized, or when they assist in resolving vague or equivocal symptoms and findings. Evoked potential studies are tests of function.  The findings usually are not etiologically specific. These types of evoked potentials are routinely performed: somatosensory, visual, and brainstem auditory.

 

Somatosensory Evoked Potentials (SSEP or SEP)

Somatosensory evoked potentials consist of a series of waves that reflect sequential activation of neural structures along the somatosensory pathways. The noninvasive clinical studies are performed by the repetitive, submaximal, electrical stimulation of a sensory or mixed sensorimotor peripheral nerve and recording the averaged responses from electrodes placed over proximal portions of the nerve stimulated, plexus, spine, and scalp. Amplitude, peak and interpeak latency measurements with side to side comparisons are used to assess abnormalities. SEP are used to aid in the determination of a diagnosis. SEP can also be performed by stimulating the skin in dermatomal areas (DSEP). The evoked potential response depends on the functional integrity of the nerve that is stimulated. SEP are an extension of the electrodiagnostic evaluation and are used to evaluate nerves that cannot be studied by conventional nerve conduction studies, including electromyography. An abnormal SEP points to a problem in the nerve conduction mechanism that carries the impulse to the brain. However, the SEP abnormality is not disease specific; an abnormal SEP indicates impairments associated with certain disorders. An abnormal SEP signifies an impaired pathway, helps to localize it, and provides a prognostic guide. The SEP does not provide any indication about the nature of the underlying pathological processes.

 

SEP are altered by impairment of the somatosensory pathway which may occur as a result of both diffuse (e.g., disease of myelin, hereditary system degenerations, coma) or local disorders (e.g., tumors, vascular lesions). SEP abnormalities can be detected in a variety of different settings. The electrophysiologic findings should be interpreted in the clinical context in which they are obtained (e.g., assessing functional integrity, diagnostic purposes, determining the course of neurological disorders, determining pathological involvement. SEP are helpful in evaluating ill-defined complaints. SEP may detect clinically silent brain lesions in multiple sclerosis suspects. Although SEP abnormalities alone are insufficient to establish the diagnosis of MS, the diagnosis can be established when there are other objective findings, such as brain plaques on MRI, clinical lesions by history and physical exam, and/or positive CSF findings (as determined by oligoclonal bands detected by established methods such as isoelectric focusing, different from any such bands in serum, or by an increased IgG index). A physician assesses the patient and determines a preliminary differential diagnosis. SEP testing may then be performed by a trained technologist under the direct supervision of a physician. Direct supervision implies that a physician is in close proximity to the patient undergoing testing, is immediately available to provide the trained technician with assistance and direction if necessary, and is responsible for determining the SEP studies that are appropriate.

 

Recordings of SEP can be normal even in patients with extreme sensory deficits due to the presence of multiple, parallel, afferent somatosensory pathways. This procedure is often performed to investigate patients with MS; various coma states, such as those from post-traumatic injury or post-anoxia; suspected brain death; and to indicate the extensiveness of lesion damage in spinal cord injuries. The return of a cortically-generated response to stimulation of a nerve below the injured portion of the cord indicates an incomplete lesion and, therefore, may offer a better prognosis.

 

SEP testing is typically performed bilaterally. Depending on the clinical situation being investigated, several nerves in one extremity may have to be tested and compared with the opposite limb. The physician’s SEP report should indicate which nerves were tested, latencies at various testing points, and an evaluation of whether the results were normal or abnormal.

 

Visual Evoked Potentials (VEP)

Visual-evoked potentials (VEP), also known as visual-evoked responses (VER), are brain waves resulting from light stimuli. VEP are used to track visual signals from the retina to the occipital cortex. With electrodes placed at occipital and parietal locations of the scalp, a checkerboard pattern is projected on a screen and rapidly reversed 100 times at a rate of once or twice per second. The procedure is performed on each eye. Occasionally, checkerboard pattern testing is difficult to use in infants or older patients, so a stroboscopic flash stimulus is used. This type of testing is severely limited due to the great variability of responses among normal persons and its relative insensitivity to clinical lesions. Visual neural impulses from either method are recorded as they travel from the eye to the occipital cortex. VEP are abnormal in patients with optic neuritis or multiple sclerosis.

 

Brain Stem Auditory Evoked Potentials (BAEP)

Brain stem auditory evoked potentials (BAEP), also known as auditory evoked potentials (AEP) or brain stem auditory evoked responses (BAER), are brain waves resulting from sound stimuli. A brief stimulus such as a sharp click is given to one ear through an earphone, while hearing in the opposite ear is masked with white noise to prevent its stimulation by transcranially conducted sound. After the acoustic stimulus, signals are generated in the auditory nerve and brainstem.

 

Depending on the amount of time elapsed between the click stimulus and the auditory evoked response, potentials are classified as early (0 to 10 msec), middle (11 to 50 msec), or late (51 to 500 msec). The early potentials reflect electrical activity at the cochlea, eighth cranial nerve, and brain stem levels. The latter potentials reflect cortical activity. In order to separate evoked potentials from background noise, a computer averages the auditory evoked responses to 1000 to 2000 clicks. Early evoked responses may be analyzed to estimate the magnitude of hearing loss and to differentiate among cochlea, eighth nerve, and brainstem lesions.

 

Sensitivity and specificity reports for these tests vary. There is no clearly established measure of comparison in the medical literature, making comparisons across studies difficult. Interobserver differences, the variety of tests employed, the presence of symptoms that may influence patient outcomes, such as pain, and the presence of abnormal imaging studies in asymptomatic patients, and the subjectivity of the physician’s interpretations may all lead to variances in sensitivity and specificity results. Despite these variances, electrodiagnostic testing is commonly used to assist in diagnosing disorders involving the nerves, muscles, and neuromuscular junction.

 

KEY POINTS:

The most recent literature update was performed through November 4, 2019. The following is a summary of the key literature to date.

 

Summary of Evidence

For individuals with spinal cord injuries, myelopathy, suspected brain death, spinocerebellar degeneration, central nervous system deficits that utilize somatosensory evoked potentials or dermatosensory evoked potentials to evaluate these disease processes. The evidence includes a prospective study, case series studies, systematic reviews, and a prospective cohort study retrospective analysis.  Relevant outcomes are overall survival, morbid events, treatment related mortality [or morbidity], symptoms, functional outcomes, and quality of life. The evidence is sufficient to determine the effects of the technology on health outcomes.

 

For individuals with increased risk for developing multiple sclerosis, to diagnose or monitor multiple sclerosis patients, to evaluate vision loss in unresponsive patients, or evaluate visual deficits utilizing visual evoked potentials. The evidence includes several case studies.  Relevant outcomes are overall survival, morbid events, treatment related mortality [or morbidity], symptoms, functional outcomes, QOL, etc. The evidence is sufficient to determine the effects of the technology on health outcomes.

 

For individuals with brain stem auditory evoked response, the evidence includes limited case studies.  Relevant outcomes are overall survival, morbid events, treatment related mortality [or morbidity], symptoms, functional outcomes, QOL, etc.). The evidence is sufficient to determine the effects of the technology on health outcomes.

 

KEY WORDS:

Somatosensory evoked potentials (SEP, SSEP), visual evoked potentials (VEP), brain stem auditory evoked potentials (BAEP, brainstem auditory evoked response (BAER), auditory evoked potentials (AEP), dermatosensory evoked potentials (DSEP), automated VEP, Diopsys NOVA VEP, Enfant VEP System, Vestibular evoked myogenic potentials , VEMP, Automated visual evoked potentials,  Comprehensive auditory evoked response testing, comprehensive otoacoustic emissions, Cognitive evoked potentials, visual P300, P3 cognitive evoked potentials, Event-related potentials, Gustatory evoked potentials, Motor evoked potentials, Cortical auditory evoked response, CAER

 

 

APPROVED BY GOVERNING BODIES:

FDA approved

 

 

BENEFIT APPLICATION:

Coverage is subject to member’s specific benefits.  Group specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply

FEP contracts: FEP does not consider investigational if FDA approved and will be reviewed for medical necessity. Special benefit consideration may apply.  Refer to member’s benefit plan.

 

 

CODING: 

CPT Codes:

 

92585

Auditory evoked potentials for evoked response audiometry and/or testing of the central nervous system; comprehensive

92586

; limited

92700

Unlisted Otorhinolaryngological Service or Procedure

95925                                     

Short-latency somatosensory evoked

potential study, stimulation of any/all

peripheral nerves or skin sites, recording

from the central nervous system; in

upper limbs

95926

; in lower limbs

95927

; in the trunk or head

95928

Central motor evoked potential study (transcranial motor stimulation); upper limbs

95929

; lower limbs

95930

Visual evoked potential (VEP), checkerboard or flash testing, central nervous system except glaucoma, with interpretation and report.

95938

Short-latency somatosensory evoked potential study, stimulation of any/all peripheral nerves or skin sites, recording from the central nervous system; in upper and lower limbs

95939

Central motor evoked potential study (transcranial motor stimulation); in upper and lower limbs

0333T

Visual evoked potential, screening of visual acuity, automated, with report

0464T

Visual evoked potential, testing for glaucoma, with interpretation and report (Effective 01/01/17)

 

                       

REFERENCES:

  1. American Academy of Neurology.  Assessment:  Dermatomal somatosensory evoked potentials.  American Academy of Neurology.  Therapeutics and Technology Assessment Subcommittee.  Neurology 1997; 49(4): 1127-1130.

  2. American Academy of Pediatrics.  Task Force on Newborn and Infant Hearing.  Newborn and infant hearing loss:  Detection and intervention. Pediatrics, February 1999, Vol. 103, No. 2, pp. 527-530.

  3. American Association of Electrodiagnostic Medicine. Somatosensory Evoked Potentials Subcommittee. Somatosensory evoked potentials: Clinical uses.  Muscle Nerve 1999; 22(Suppl 8): S111-S118.

  4. American Association of Electrodiagnostic Medicine (AAEM). Guidelines for somatosensory evoked potentials. The AAEM Somatosensory Evoked Potentials Subcommittee, 1998.

  5. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM), American Academy of Neurology (AAN), and American Academy of Physical Medicine and Rehabilitation (AAPMR).  Recommended policy for electrodiagnostic medicine. June 2004, //www.aanem.org. 

  6. American Academy of Neurology.  Practice parameters: Determining brain death in adults (Summary statement). The Quality Standards Subcommittee of the American Academy of Neurology. Neurology 1995; 45: 1012-1014.

  7. American Clinical Neurophysiology Society 2008. Standards for short latency somatosensory evoked potentials.

  8. Bhattacharyya N. Auditory brainstem response audiometry.  //emedicine.medscape.com/article/836277-print, updated January 2009.

  9. Bradley: Neurology in Clinical Practice, 5th edition, 2008. Evoked Potentials.

  10. Chawla J and Burneo J. Somatosensory evoked potentials, clinical applications. //emedicine.medscape.com. Update December 2008.

  11. Courtney AM, et al. Multiple sclerosis. Medical Clinics of North America, March 2009, Vol. 93, Issue 2.

  12. Cruecu G, et al. Recommendations for the clinical use of somatosensory-evoked potentials. Clinical Neurophysiology, August 2008; 119(8): 1705-1719.

  13. Dangond F. Multiple sclerosis. //emedicine.medscape.com/article/1146199-print. Updated January 2010.

  14. Gronseth GS and Ashman EJ. Quality Standards Subcommittee of the American Academy of Neurology. Practice parameter: The usefulness of evoked potentials in identifying clinically silent lesions in patients with suspected multiple sclerosis (an evidence-based review). Neurology 2000; 54: 1720-1725.

  15. Harlor Jr AD and Bower C.  Hearing assessment in infants and children:  Recommendations beyond neonatal screening.  Pediatrics, October 2009; 124(4): 1252-1263.

  16. Joint Committee on Infant Hearing. Year 2000 position statement: Principles and guidelines for early hearing detection and intervention programs. Pediatrics, October 2000, Vol. 106, No. 4, pp. 798-817.

  17. Joint Committee on Infant Hearing. Year 2007 position statement: Principles for early hearing detection and intervention programs. Pediatrics, October 2007, Vol. 120, No. 4, pp. 897-921.

  18. Laron M, et al. Assessing visual pathway function in multiple sclerosis patients with multifocal visual evoked potentials. Multiple Sclerosis, December 2009; 15(12): 1431-1441.

  19. Legatt AD. Somatosensory evoked potentials, general principles. //emedicine.medscape.com. Updated September 2009.

  20. Lin Ming-Lee, et al. Vestibular evoked myogenic potentials (VEMP) can detect asymptomatic saccular hydrops. Laryngoscope, June 2006; 116(6): 987-992.

  21. Loncarevi AN, et al. Somatosensory evoked potentials (SSEP) in multiple sclerosis. Medicinski Arkiv, January 2008; 62(2): 80-81.

  22. National Collaborating Centre for Chronic Conditions. Multiple sclerosis. National Clinical Guideline for diagnosis and management in primary and secondary care. National Institute for Clinical Excellence (NICE) 2004.

  23. Odom JV, et al. Visual evoked potentials standard (2004). Documenta Ophthmologica, March 2004, Vol. 108, No. 2.

  24. Rosengren SM, et al. Vestibular evoked myogenic potentials: Past, present, and future.  Clinical Neurophysiology, January 2010.

  25. Rothstein TL. The role of evoked potentials in anoxic-ischemic coma and severe brain trauma. Journal of Clinical Neurophysiology, September 2000; 17(5): 486-497.

  26. U.S. Preventive Services Task Force. Universal screening for hearing loss in newborns recommendation statement. Pediatrics 2008; 122: 143-148.

 

 

POLICY HISTORY:

Medical Policy Group, March 2010 (2)

Medical Policy Group, April 2010 (2)

Medical Policy Administration Committee May 2010

Available for comment May 7-June 21, 2010

Medical Policy Group, December 2011 (3): Added new 2012 Codes – 95938 & 95939

Medical Policy Group, September 2012: Effective September 14, 2012 this policy is no longer scheduled for regular literature reviews and updates.

Medical Policy Group, June 2013 (1) Updated policy statement for VEP section stating automated VEP testing is investigational; added new code 0333T related to automated VEP testing to policy effective for 7/1/2013; added automated VEP, Diopsys NOVA VEP, and Enfant VEP System to Key Words

Medical Policy Administration Committee June 2013

Available for comment May 30 through July 13, 2013

Medical Policy Group, December 2016: 2017 Annual Coding Update. Added new CPT code 0464T to current coding.

Medical Policy Group, December 2017. Annual Coding Update 2018. Updated verbiage for revised codes 95930 and 0333T.

Medical Policy Group, January 2018 (6): Updated Key Words to include : Vestibular evoked myogenic potentials , VEMP, Automated visual evoked potentials,  Comprehensive auditory evoked response testing, comprehensive otoacoustic emissions, Cognitive evoked potentials, visual P300, P3 cognitive evoked potentials, Event-related potentials, Gustatory evoked potentials, Motor evoked potentials, Cortical auditory evoked response, CAER. Added 92700 to Coding Section. No change to policy statement.

Medical Policy Group, November 2019 (3): 2019 Updates to Key Points. A peer reviewed literature analysis was completed and no new information was identified that would alter the coverage statement of this policy.

 

 

 

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

 

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

 

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.