Electrocochleography (ECochG) for Meniere’s Disease

One of my biggest frustrations with Meniere’s disease is that there’s no single definitive test. I can’t just do one test and say, “Yes, this patient has Meniere’s, confirmed.” I have to piece together the clinical story, audiometry, vestibular testing, and sometimes imaging.

But electrocochleography, ECochG, gets me closer to an objective diagnosis than almost any other test. It’s measuring something fundamental about Meniere’s disease: the pressure buildup in the inner ear that’s causing the problem in the first place.

Understanding Meniere’S Disease

What Is ECochG?

ECochG (electrocochleography) measures electrical potentials generated by the inner ear when sound stimulates it. But more importantly for Meniere’s, it indirectly measures endolymph pressure.

Here’s the physics: the inner ear has two fluid compartments, perilymph and endolymph. Normally they’re balanced. But in Meniere’s disease, endolymph pressure builds up (endolymphatic hydrops). That pressure distorts the structures of the inner ear, the cochlea and vestibule, and that distortion changes the electrical signals the ear generates.

ECochG measures these electrical signals and specifically looks for signs of that abnormal pressure.

The Summating Potential and Action Potential

There are two main electrical potentials measured in ECochG:

Summating Potential (SP)

This is a sustained electrical potential that develops when sound stimulates the cochlea. In Meniere’s disease, the distorted cochlea generates an abnormally large summating potential.

Action Potential (AP)

This is the electrical response from the auditory nerve fibers firing in response to sound. It’s normal in Meniere’s, the nerve itself isn’t damaged, just overstimulated by the abnormal pressure.

The SP/AP Ratio

This is the key diagnostic number. In a normal ear, the ratio is about 0.25 to 0.35. The action potential is much larger than the summating potential.

👉 Also read: Meniere’s disease guide

But in Meniere’s disease, the summating potential gets bigger relative to the action potential. An SP/AP ratio of 0.40 or higher is considered elevated and consistent with endolymphatic hydrops.

The higher the ratio, the more endolymph pressure is presumed to be present. Some labs use different cutoff values (0.35 or even 0.30), so I always look at my lab’s reference values.

How ECochG Test Is Performed

There are two main ways to do ECochG:

Tympanic Membrane Electrode Method

This is the most common approach in my experience. An electrode is placed on the surface of the tympanic membrane (eardrum), a procedure similar to placing a pressure-equalizing tube but just for recording, not for ventilation.

Here’s the procedure:

1. Preparation: The ear canal is cleaned with alcohol or a disinfectant.
2. Anesthesia: Topical anesthesia (usually lidocaine) is applied to the ear canal.
3. Electrode placement: Using an otoscope or microscope, the electrode is positioned on the tympanic membrane. It’s usually a small silver pellet electrode or a thin needle electrode.
4. Grounding: Additional electrodes are placed on the forehead or neck for reference and ground.
5. Sound stimulus: The ear receives pure tone sounds at different frequencies, usually 1000 Hz is standard.
6. Recording: The electrical potentials are recorded and displayed on a computer screen.
7. Analysis: The summating potential and action potential are identified and measured, and the SP/AP ratio is calculated.

The test takes about 15-20 minutes per ear. Both ears are usually tested.

Extratympanic Electrode Method

A less invasive approach where the electrode is placed just outside the eardrum in the ear canal without direct tympanic contact. This is less sensitive than tympanic placement but more comfortable for the patient. Some ears are harder to access (very small canals, cerumen impaction), so this can be helpful.

What ECochG Results Tell Me

Normal ECochG

SP/AP ratio is normal (0.25-0.35 or depending on lab values). This makes Meniere’s disease less likely. The patient probably has something else, maybe migraine-associated vertigo, or psychiatric dizziness, or BPPV that wasn’t caught.

👉 Also read: Electrocochleography (ECochG), Diagnosing Meniere’s Disease Precisely

Elevated SP/AP Ratio

Ratio is 0.40 or higher. This is consistent with endolymphatic hydrops and supports the diagnosis of Meniere’s disease, especially if combined with the classic symptoms (vertigo, hearing loss, tinnitus).

Important: not all elevated ECochG is Meniere’s. Other conditions causing inner ear fluid imbalance can elevate the ratio. But in the right clinical context, it’s very supportive of Meniere’s.

Asymmetric ECochG

One ear has a clearly elevated ratio, the other is normal. This tells me the Meniere’s is unilateral (affecting one ear), which is the typical presentation. Bilateral Meniere’s (both ears affected) is rare.

Using ECochG in Meniere’s Diagnosis

Here’s how I typically approach Meniere’s diagnosis with ECochG:

First episode of suspected Meniere’s: I get audiometry, vestibular testing, and usually ECochG to support the diagnosis. An elevated SP/AP ratio plus the clinical symptoms makes me confident about the diagnosis. I usually also do MRI to rule out acoustic neuroma or MS.

Recurrent vertigo with typical symptoms: If the patient has a prior diagnosis of Meniere’s and this looks like another attack, I might not repeat ECochG. I manage based on clinical symptoms.

Meniere’s suspected but unusual features: If something about the case is atypical, maybe the hearing loss is in a different frequency pattern, or the patient has bilateral symptoms, ECochG helps me figure out whether this is really Meniere’s or something else.

Severe Meniere’s considering surgery: Sometimes I repeat ECochG to check if the SP/AP ratio is still elevated. If it’s normalized on repeat testing, it might indicate successful medical management has reduced the endolymph pressure. If it’s still elevated despite medical treatment, it supports the idea that surgery might be needed.

👉 Also read: Meniere’s Disease Symptoms, The Four Classic Signs Explained

ECochG vs Other Meniere’s Diagnostic Tests

I use ECochG along with other tests:

Audiometry: Shows the hearing loss pattern, classic Meniere’s has low-frequency loss. ECochG is elevated. Both together are very supportive of Meniere’s.

VEMP testing: Tests otolith function. In advanced Meniere’s, VEMP might be abnormal. ECochG and VEMP together give me information about the extent of damage.

Caloric or rotational chair testing: Tests the balance canals. In Meniere’s, these tests might show increased excitability (too-strong response to stimulus) because the pressure-distorted canal is more sensitive.

MRI: Doesn’t directly diagnose Meniere’s but rules out other causes of similar symptoms like acoustic neuroma or multiple sclerosis.

ECochG is the most specific test for endolymphatic hydrops, which is the underlying pathology of Meniere’s.

Sensitivity and Specificity of ECochG

In Meniere’s disease with active symptoms, ECochG has sensitivity around 60-70% (meaning about 60-70% of true Meniere’s cases show elevated SP/AP) and specificity around 80-90% (meaning if ECochG is elevated, it’s likely Meniere’s, though not always).

These numbers mean:

👉 Also read: Meniere’s Disease: Complete Guide to Symptoms, Diagnosis

• A normal ECochG doesn’t rule out Meniere’s, you might have the disease but the test misses it
• An elevated ECochG strongly suggests Meniere’s but could be something else
• Clinical correlation is essential, I can’t diagnose Meniere’s on ECochG alone

When I Order ECochG

I order ECochG when:

• First diagnosis of suspected Meniere’s, to support the clinical diagnosis objectively
• Recurrent vertigo with hearing changes, to confirm Meniere’s vs other causes
• Unilateral vertigo with tinnitus and hearing loss, classic triad that needs confirmation
• Severe Meniere’s being considered for surgery, baseline assessment and possibly repeat post-treatment
• Atypical presentation, to help determine if this is really Meniere’s or something else

I don’t order ECochG for simple BPPV, vestibular neuritis, or obvious labyrinthitis. The clinical diagnosis is clear in those cases.

My Clinical Experience

I had a 48-year-old woman with recurrent vertigo, progressive hearing loss, and tinnitus in one ear. The picture looked like Meniere’s, but I wanted to be sure before committing her to years of Meniere’s management. ECochG showed SP/AP ratio of 0.52 on the affected side, clearly elevated. Combined with her audiometry (low-frequency loss) and clinical history, I was confident about the Meniere’s diagnosis.

Another case: 55-year-old man with recurrent vertigo but normal hearing, which is unusual for Meniere’s. ECochG was normal. That result made me reconsider, probably not Meniere’s. Further workup revealed perilymph fistula instead. Different diagnosis, different treatment.

Limitations of ECochG

ECochG measures endolymphatic pressure indirectly. A very elevated ratio suggests hydrops, but there’s no absolute numerical cutoff where you know for certain that hydrops is present. The test is somewhat operator-dependent, electrode placement matters.

Also, some patients have elevated SP/AP without having Meniere’s symptoms, asymptomatic hydrops. And as I noted, some true Meniere’s cases have normal ECochG despite clear endolymphatic hydrops at surgery.

So ECochG is helpful but not perfectly sensitive or specific. It’s one piece of the diagnostic puzzle, not the whole puzzle.

The Bottom Line

ECochG measures electrical signals generated by the inner ear that reflect endolymphatic pressure. In Meniere’s disease, the SP/AP ratio is typically elevated. When combined with clinical symptoms (vertigo, hearing loss, tinnitus) and audiometric findings (low-frequency loss), an elevated ECochG strongly supports the diagnosis of Meniere’s disease.

👉 Also read: Meniere’s Disease Low Sodium Diet: Complete Indian Food Guide

It’s not a perfect test, but it’s one of my most useful objective measures for Meniere’s. If you have suspected Meniere’s disease, ask whether ECochG might be helpful for confirming your diagnosis.

Need Meniere’s Disease Evaluation?

If you have recurrent vertigo with hearing changes and suspect you might have Meniere’s disease, call me at 7393062200 or WhatsApp https://wa.me/917393062200 to schedule a complete diagnostic evaluation including ECochG at Prime ENT Center in Hardoi.

---

FAQ Schema

---

About Dr. Prateek Porwal

Dr. Prateek Porwal is an ENT & Vertigo Specialist with over 13 years of experience, holding MBBS (GSVM Medical College), DNB ENT (Tata Main Hospital), and CAMVD (Yenepoya University). He is the originator of the Bangalore Maneuver for Anterior Canal BPPV and has published research in Frontiers in Neurology and IJOHNS. Serving at Prime ENT Center, Hardoi.

---

Medical Disclaimer: This article is for educational purposes only and does not constitute medical advice, diagnosis or prescribing guidance. Consult Dr. Prateek Porwal at Prime ENT Center, Hardoi for personalised treatment.

References

1. Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Meniere’s disease. Otolaryngology–Head and Neck Surgery. 1995;113(3):181–185.
2. Thirlwall AS, Kundu S. Diuretics for Ménière’s disease or syndrome. Cochrane Database of Systematic Reviews. 2006;(3):CD003599.
3. Pullens B, van Benthem PP. Intratympanic an ototoxic antibiotic for unilateral Menière’s disease or syndrome. Cochrane Database of Systematic Reviews. 2011;(3):CD008234.