Electrocochleogram and Perilymphatic Pressure Measurement

Number: 0564

  1. Aetna considers electrocochleography (ECOG) medically necessary for evaluation of members with symptoms of episodic dizziness (vertigo, imbalance) or tinnitus, to rule out endolymphatic hydrops (Meniere's disease) and perilymphatic fistula. 

  2. Aetna considers ECOG medically necessary when performed with auditory brainstem response (ABR) testing of members with profound hearing loss.

  3. Aetna considers ECOG experimental and investigational for routine screening of hearing impairment, and for all other indications because of insufficient evidence of its clinical value for these indications.

  4. Aetna considers measurement of perilymphatic pressure experimental and investigational because its value in the management of individuals with Meniere's disease or idiopathic sudden sensorineural hearing loss has not been established.


Meniere's Syndrome/Endolymphatic Hydrops

Meniere's disease or Meniere's syndrome is a potentially disabling condition involving varying degrees of fluctuating hearing loss, fluctuating tinnitus, episodic vertigo, and aural fullness (a feeling of fullness, pressure and discomfort in the ear).  The syndrome may be idiopathic, in which case it is called Meniere's disease, or secondary to various processes that interfere with the normal resorption of endolymph (e.g., neurosyphilis, viral infections, trauma, congenital anomalies, etc.).  The disease appears to strike most commonly persons between 30 and 60 years of age, with men and women affected equally.  Incidence of the disease is approximately 250 per million populations.  Patients with Meniere's disease have a progressive distention of the endolymphatic space of the inner ear, caused by fluid build-up of the endolymphatic space (endolymphatic hydrops), caused either by overproduction or reduced adsorption.  The increased pressure exposes cochlear hair cells responsible for sensing movement and balance to progressive damage and paralysis, resulting in attacks of dizziness, often with nausea and vomiting.

Early in the course of disease, these attacks are usually brief (lasting 1 hour or so), as the damage to the cochlear hair cells is temporary and the hair cells resume normal function when the hydrops resolves.  Chronic repetitive attacks may lead to irreversible damage to the hair cells, and hearing loss can become permanent.  The hearing loss and tinnitus are usually unilateral, although up to a quarter of patients may go on to develop a severe bilateral disorder.

Trans-tympanic electrocochleography (ECOG) can be used to confirm cochlear involvement in hearing loss, and is an objective test for endolymphatic hydrops.  Electrocochleography measures the ratio of the summating potential (SP) and the action potential (AP) on the most peripheral portion of the auditory system in response to auditory stimuli.  The AP is the summed or averaged activity of the APs of the auditory nerve, which are elicited by acoustic stimulation.  The SP is generated by the hair cells of the cochlea in response to acoustic stimulation.  Surface electrodes, such as those used in auditory brainstem response, can not record these potentials; electrodes must be placed on or through the tympanic membrane.  In ECOG, a fine needle is passed through an anesthetized tympanic membrane and placed in contact with the cochlear hair cells of the inner ear in order to record electrical activity from these cells.  The ear is exposed to a train of about 1,000 click or tonal stimuli, and APs from auditory neurons are recorded for 10 milliseconds after each click.  This information is recorded and summated by computer.  Patients with endolymphatic hydrops have abnormal waveforms (widening of the waveform with multiple peaks).  Endolymphatic hydrops is suggested when the ratio of the summating potential to the AP is greater than 35 %.

Electrocochleography allows the diagnosis of Meniere's disease to be confirmed or refuted so that appropriate prognostic advice can be given together with medical or surgical treatments if indicated.

In all patients who have unilateral persistent otological symptoms, a MRI is required to exclude acoustic neuroma, which can mimic the presentation of Meniere's disease.  Meniere's is confirmed with an electrocochleogram so that appropriate effective treatments can be applied.

Acute attacks of Meniere's syndrome are treated with anti-emetics and sedatives.  Long-term treatment is usually medical, including rigid salt restriction and diuretics.  Occasionally chemoablation (intra-tympanic gentamycin) or surgical ablation (labyrinthectomy when hearing is already lost, vestibular nerve section when it is not) is necessary for refractory disease.

Perilymphatic Fistula

Electrocochleography has also been used to determine the presence of perilymphatic fistula, based on the SP/AP amplitude ratio.  A perilymph fistula (perilymphatic fistula, labyrinthine fistula) is an abnormal communication between the fluid-filled perilymphatic space of the inner ear and the air-filled middle ear cavity, usually through the round or oval windows.  This results in sensori-neural hearing loss and/or vestibular symptoms.

Most commonly, a tear in the round or oval window leads to loss of perilymph into the middle ear.  This may be the result of stapes prosthesis surgery, trauma, barotrauma, bony erosion due to infection or neoplasm, or it may be idiopathic.  In children, it is associated with congenital anomalies of the middle or inner ear.

Symptoms of perilymphatic fistula are similar to Meniere's disease, and include sensori-neural hearing loss, which may be sudden or fluctuating; aural fullness; and vestibular symptoms (vertigo (with or without head position changes), dysequilibrium, motion intolerance, nausea and vomiting, disorganization of memory and concentration, and perceptual disorganization in complex surroundings (such as crowds or traffic)).  Tinnitus occurs in some cases, and can be roaring.  In the absence of prior surgery or definite traumatic event, it may be difficult to distinguish a perilymph fistula from Meniere's syndrome.

In addition to ECOG, other tests that may be used by otologists for the diagnosis of perilymph fistula include audiograms to detect hearing loss and fistula tests.  The subjective fistula test is performed by applying positive and negative pressure to the intact eardrum using a pneumatic otoscope.  Positive results include the elicitation of nystagmus or onset of dysequilibrium with the sensation of motion or nausea.  Some otologists administer the test with electronystagmography or using a specialized platform.  Rigid or flexible endoscopy is performed to look for visible tears or fluid in the middle ear.  The final diagnosis is made by direct inspection at the time of surgery, with visualization of perilymph fluid in the middle ear cavity.

Medical therapy is rarely reported.  There are some reports of spontaneous healing with bedrest, head elevation to 30 degrees, and avoidance of lifting or middle ear pressure-increasing activities.  Surgical treatment is available if conservative therapy fails.

Severe Sensori-Neural Deafness

Another clinical application of ECOG is identification of wave I of the auditory brainstem response (ABR) during combined ECOG-ABR testing, as wave I is frequently difficult to detect in patients with profound hearing loss when ECOG is not performed in conjunction with ABR testing.  Auditory brainstem response testing involves the measurement of responses along the auditory pathway from cranial nerve VIII to the lateral lemniscus of the auditory brainstem.  Five distinct electric waveforms generated in the 8th nerve, brainstem, and other regions in response to acoustic stimulation are examined.  Wave I is generated at the distal part of the auditory nerve.

Screening for Hearing Impairment

According to the U.S. Preventive Services Task Force, ECOG is not an appropriate test for routine screening for hearing impairment.

Electrocochleography is available in virtually all otolaryngology departments, takes only 20 mins or so and requires an otolaryngologist and usually an audiologist.

Perilymphatic Pressure Measurement

Assessment of perilymphatic pressure has also been used to diagnose Meniere's disease.  However, published reports do not support a diagnostic role for this approach.  Rosingh and colleagues (1996) did not find any significant differences in perilymphatic pressure measurements between patients with Meniere's disease and young normal hearing subjects.  This is in accordance with the findings of Ayache and associates (2000) who concluded that assessment of perilymphatic pressure does not seem to be useful in Meniere's disease.  Furthermore, Rosingh and co-workers (2000) reported that perilymphatic pressure measured in the affected ear of patients with Meniere's disease or idiopathic sudden sensori-neural hearing loss did not differ significantly from the pressure in the non-affected and normal hearing ear.  In a follow-up study by Ayache et al (2002), the authors concluded that perilymphatic pressure measurements by means of the Tympanic Displacement Analyzer are not useful in the evaluation of patients with Meniere’s disease.

CPT Codes / HCPCS Codes / ICD-10 Codes
Information in the [brackets] below has been added for clarification purposes.   Codes requiring a 7th character are represented by "+":
ICD-10 codes will become effective as of October 1, 2015:
CPT codes covered if selection criteria are met:
92584 Electrocochleography
Other CPT codes related to the CPB:
70540 Magnetic resonance (e.g., proton) imaging, orbit, face, and/or neck; without contrast material(s)
70542     with contrast material(s)
92585 Auditory evoked potentials for evoked response audiometry and/or testing of the central nervous system; comprehensive
92586     limited
92587 Evoked otoacoustic emissions; limited (single stimulus level, either transient or distortion products)
92588     comprehensive or diagnostic evaluation (comparison of transient and/or distortion product otoacoustic emissions at multiple levels and frequencies)
ICD-10 codes covered if selection criteria are met:
H81.01 - H81.09 Meniere's disease
H81.10 - H81.13
H81.311 - H81.49
H83.11 - H83.19 Labyrinthine fistula
H83.3X1 - H83.3X9 Noise effects on inner ear
H90.3 Sensorineural hearing loss, bilateral
H90.41 - H90.42 Sensorineural hearing loss, unilateral, with unrestricted hearing on the contralateral side
H90.5 Unspecified sensorineural hearing loss
H90.6 - H90.8 Mixed conductive and sensorineural hearing loss
H91.20 - H91.23 Sudden idiopathic hearing loss
H91.8X1 - H91.8X9 Other specified hearing loss
H93.11 - H93.19 Tinnitus
R26.89 Other abnormalities of gait and mobility [imbalance]
R42 Dizziness and giddiness
ICD-10 codes not covered for indications listed in the CPB (not all-inclusive):
Z01.10 Encounter for examination of ears and hearing without abnormal findings [routine screen without signs/symptoms]
Z01.110 Encounter for hearing examination following failed hearing screening [routine screen without signs/symptoms]

The above policy is based on the following references:


    1. Bates G. Electrocochleogram. Test of the Month. Bandolier 1995;19(4). Available at: Accessed April 26, 2001.
    2. Gibson WPR, Ramsden RTR, Moffat DA. Clinical electrocochleography and diagnosis and management of Ménière's disorder. Audiology. 1977;16:389-401.
    3. No authors listed. Ménière's disease. Bandolier 1995;13(1). Available at: Accessed April 26, 2001.
    4. Saeed SR, Birzgalis AR, Ramsden RT. Ménière's disease. Br J Hosp Med. 1994;51:603-612.
    5. U.S. Preventive Services Task Force. Screening for hearing impairment. In: Guide to Clinical Preventive Services: Report of the U.S. Preventive Services Task Force. 2nd ed. Philadelphia, PA: WB Saunders Co.; 1996.
    6. Silverman CA. Audiologic assessment and amplification. Primary Care Clin Office Pract. 1998;25(3):545-581.
    7. Bhansali SA. Perilymph fistula. Ear Nose Throat J. 1989;68(1):11, 14-16, 21-28.
    8. Meyerhoff WL, Marple BF. Perilymphatic fistula. Otolaryngol Clin North Am. 1994;27(2):411-426.
    9. Logan JR. Perilymph fistula. eMedicine Emergency Medicine Topic 414. Omaha, NE:; February 6, 2001. Available at: Accessed April 26, 2001.
    10. Hearing loss. In: Merck Manual of Diagnosis and Therapy. 17th ed. MH Beers, R Berkow, eds. Ch. 82, Sec. 7. White House Station, NJ: Merck Research Laboratories; 1999. Available at: Accessed April 26, 2001.
    11. Mezzalira R, Maudonnet OA, Pereira RG, Ninno JE. The contribution of otoneurological evaluation to tinnitus diagnosis. Int Tinnitus J. 2004;10(1):65-72.
    12. Kim HH, Wiet RJ, Battista RA. Trends in the diagnosis and the management of Meniere's disease: Results of a survey. Otolaryngol Head Neck Surg. 2005;132(5):722-726.
    13. Ferraro JA, Durrant JD. Electrocochleography in the evaluation of patients with Meniere's disease/endolymphatic hydrops. J Am Acad Audiol. 2006;17(1):45-68.
    14. Nabi S, Parnes LS. Bilateral Ménière's disease. Curr Opin Otolaryngol Head Neck Surg. 2009;17(5):356-362.
    15. Ferraro JA. Electrocochleography: A review of recording approaches, clinical applications, and new findings in adults and children. J Am Acad Audiol. 2010;21(3):145-152.
    16. Nguyen LT, Harris JP, Nguyen QT. Clinical utility of electrocochleography in
      the diagnosis and management of Ménière's disease: AOS and ANS membership survey data. Otol Neurotol. 2010;31(3):455-459.
    17. Moon IJ, Park GY, Choi J, et al. Predictive value of electrocochleography for determining hearing outcomes in Ménière's disease. Otol Neurotol. 2012;33(2):204-210.
    18. Roland PS. Perilymphatic fistula. eMedicine Surgery. New York, NY: WebMD, LLC; updated April 26, 2010.
    19. Vassiliou A, Vlastarakos PV, Maragoudakis P, et al. Meniere's disease: Still a mystery disease with difficult differential diagnosis. Ann Indian Acad Neurol. 2011;14(1):12-18.
    20. Lamounier P, Gobbo DA, Souza TS, et al. Electrocochleography for Ménière's disease: Is it reliable? Braz J Otorhinolaryngol. 2014;80(6):527-532.

    Perilymphatic Pressure Measurement

    1. Rosingh HJ, Wit HP, Albers FW. Non-invasive perilymphatic pressure measurement in patients with Meniere's disease. Clin Otolaryngol. 1996;21(4):335-338.
    2. Friedland DR, Wackym PA. A critical appraisal of spontaneous perilymphatic fistulas of the inner ear. Am J Otol. 1999;20(2):261-276; discussion 276-279.
    3. Rosingh HJ, Albers FW, Wit HP. Noninvasive perilymphatic pressure measurement in patients with Meniere's disease and patients with idiopathic sudden sensorineural hearing loss. Am J Otol. 2000;21(5):641-644.
    4. Ayache D, Nengsu Tchuente A, Plouin-Gaudon I, et al. Assessment of perilymphatic pressure using the MMS-10 tympanic membrane displacement analyzer (Marchbanks' test) in patients with Meniere's disease: Preliminary report. Ann Otolaryngol Chir Cervicofac. 2000;117(3):183-188.
    5. Mateijsen DJ, Rosingh HJ, Wit HP, et al. Perilymphatic pressure measurement in patients with Meniere's disease. Eur Arch Otorhinolaryngol. 2001;258(1):1-4.
    6. Ayache D, Plouin-Gaudon I, Bouzerar K, Elbaz P. Perilymphatic pressure measurement in Meniere's disease. Ann Otol Rhinol Laryngol. 2002;111(7 Pt 1):653-656.

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