The Clinical Value of Extratympanic Electrocochleography in the Diagnosis of Ménière’s Disease

Abstract

Objective: To evaluate the clinical conditions causing an elevation in the click-evoked summation potential (SP)/action potential (AP) amplitude ratio (SP/AP ratio), the cause of the SP enhancement in Ménière’s disease (MD) and the diagnostic efficacy of electrocochleography (ECoG) were discussed. Study Design: Retrospective case review. Setting: An outpatient clinic of the Otolaryngology Department of Kochi Medical School. Patients: ECoG testing was performed in 632 patients (727 ears) with vertigo/dizziness and/or deafness over a 10-year period (1995–2005). Among them, 334 patients had diagnoses of definite MD, including 95 cases of bilateral involvement. Main Outcome Measures: Audiological thresholds and SP/AP ratio. Results: An enhanced SP was observed in 56.3% of patients with MD. The incidence of an enhanced SP was low in patients for whom the disease duration was 2 years or less and the frequency of attacks was once a year or less, but was significantly higher in cases where the disease duration was 2 years or longer and/or the frequency of attacks was several times a year (Games-Howell test, p < 0.05). The incidence of an enhanced SP was significantly elevated in cases with pure-tone average exceeding 31 dB (Kendall’s rank correlation test, p < 0.001). However, the enhanced SP, once it appeared, did not always disappear in spite of hearing improvement. Hearing improvement induced by the glycerol test also produced no alteration in an SP/AP ratio, and there was no significant difference between the glycerol test results and the incidence of an enhanced SP (χ² goodness-of-fit test). Conclusions: The longer the patients were symptomatic or the severer the ear symptoms, the more likely the ECoG was to be positive. The abnormally elevated SP, once it had appeared, persisted for long periods. Spontaneous and glycerol-induced hearing gains did not result in a decrease in SP/AP ratio. These clinical characteristics of ECoG seem to indicate that the enhanced SP in MD might be caused by the malfunction of hair cells, not by the displacement of the basilar membrane toward the scala tympani.

Diagnostic Usefulness of Multifrequency Tympanometry for Ménière’s Disease

“…The sensitivities and specificities of the Y width and RF values in the present study were at a similar or lower level relative to other tests for detecting endolymphatic hydrops, such as ECochG and VEMP. The sensitivity and specificity of ECochG in the diagnosis of MD have been reported to be 55-85 and 80-96%, respectively [Sass, 1998;Chung et al, 2004;Iseli and Gibson, 2010;Takeda and Kakigi, 2010]. Recently, Iseli and Gibson [2010] showed that by biasing the summation potential with low-frequency tone stimuli the sensitivity and specificity of ECochG were raised to 85 and 80.6%, respectively, separating MD patients from non-MD patients with an accuracy of 85% [Iseli and Gibson, 2010].…”

Can we use electrocochleography as a clinical tool in the diagnosis of Meniere’s disease during the early symptomatic period?

“…Meniere's disease is a condition characterized by repeated vertiginous episodes accompanied by fluctuating hearing loss, tinnitus, and aural fullness [1][2][3]. However, symptom presentation can be vague and variable depending on the duration of the episodes.…”

“…The guidelines have also provided a means to stage patients based on their audiometric status. Although the AAO-HNS's guidelines are applied to Meniere's disease based on clinical symptoms and audiometric data, most clinicians have felt the need for objective diagnostic tools [2][3][4][5]. To date, there is no objective, gold standard method for the diagnosis of Meniere's disease.…”

Is dehydration test using isosorbide useful in Meniere’s disease?

“…Thus, we decided to use a simple non-invasive extratympanic form of ECoG. Takeda and Kakigi [12] reported that 56% of MD patients exhibited abnormal extratympanic ECoG findings, while that proportion was 44% in our study.…”