Nguyen, Harris, and Nguyen (2010) report diagnosis of Meniere’s Disease (MD) is based on the history (or presence) of fluctuating hearing loss, tinnitus, aural pressure, and episodic vertigo. They received 143 responses to their survey from members of the American Otological Society and the American Neurotology Society. Based on received responses, Nguyen, Harris, and Nguyen report only 18 percent of clinicians (surveyed) use electrocochleography (ECoG) routinely, half (46 percent) do not use ECoG at all and 37 percent report using it in "questionable" (difficult to diagnose) cases. The authors stated ECoG has little or no role with regard to diagnosing or managing MD. Ferraro (2010) pointed out although symptomatic patients who present with enlarged SP/AP ratios are likely to receive a diagnosis of MD, only half the patients with confirmed MD have enlarged SP/AP ratios—and ECoG is not viable when hearing thresholds between 1000 and 4000 Hz exceed 45 dB HL as the amplitude relationships present with greater variability.
Ferraro, Beck, and Speidel (2011) report the clinical utility of ECoG (with respect to the diagnosis of MD) is limited as only some 60 percent of patients with MD are likely to have an enlarged SP/AP amplitude ratio. Further, they report a general "lack of standardization" with regard to acquiring and recording ECoGs. Nonetheless, the cochlear microphonic (one of the three key components of ECoG) remains a valuable tool with respect to the diagnosis of Auditory Neuropathy Spectrum Disorder and ECoG remains a valuable component of many protocols used to determine auditory thresholds. With regard to diagnosing MD or endolymphatics hydrops, Ferraro, Beck, and Speidel report ECoG is generally more useful in the early stages—when the patient’s hearing is normal or when only a mild (to moderate) hearing loss is present, and importantly, ECoGs utility decreases as hearing loss and symptoms increase.
Buki, Junger, and Avan (2012) report the effectiveness of administration of intratympanic gentamicin injections in patients with MD. Buki, Junger, and Avan report 62 patients with "definite" MD. Based on their diagram (Figure 2) it appears 62 symptomatic ears presented with an average hearing loss of approximately 60 to 65 dB HL. They report average SP amplitude values were significantly higher on the involved (MD) side and average AP values did not differ (across MD and non-MD ears) significantly. The authors report they obtained ECoGs on 40 ears pre-and-post intratympanic gentamicin injection. On the non-MD (i.e., normal) side, Buki, Junger and Avan report significant correlations (Spearman r=0.62) between pre and post injection SP/AP measures. However, on the MD side, no correlation was demonstrated (Spearman r=0.32). They note "The clinical course of MD can vary substantially…" and "the assessment of the potential effectiveness of a therapeutic procedure may be difficult…" Nonetheless, Buki, Junger and Avan report "…ECoG is seldom used clinically for diagnosing MD…" due to the overlap of normal and pathologic values (often determined when defining ECoG as ‘abnormal’ when the SP/AP ratio is greater than 40%). However, they offer a "new criterion" for analysis of ECoG. Specifically, they report a "strong (threefold) asymmetry of the SP/AP ratio (e.g. 10 percent on the healthy side and 30 percent on the involved side)…" They note, of the six cases which met this criterion, intratympanic gentamicin injections were successful.
For More Information, References, and Recommendations
Buki B, Junger H, Avan P. (2012) Cochlear Function in Meniere’s Disease. International Journal of Audiology 51:373-378.
Ferraro JA. (2010) Electrocochleography: A Review of Recording Approaches, Clinical Applications, and New Findings in Adults and Children. Journal of the American Academy of Audiology 21(3):145-152.
Ferraro JA, Beck DL, Speidel DP. (2011) Developments in Electrocochleography: 2011. Hearing Review, July.
Nguyen LT, Harris JP, Nguyen, QT. (2010) Clinical Utility of Electrocochleography in the Diagnosis and Management of Meniere's Disease: AOS and ANS Membership Survey Data. Otology & Neurotology 31(3):455-459.