A Review of Electrocochleography: Instrumentation Settings and Meta-analysis of Criteria for Diagnosis of Endolymphatic Hydrops

Abstract

Wuyts FL, Van de Heyning PH, Van Spaendonck MP, Molenberghs G. A review of electrocochleography: instrumentation settings and meta-analysis of criteria for diagnosis of endolymphatic hydrops. Acta Otolaryngol (Stockh) 1997; Suppl 526: 14–20.

This paper reviews the literature on instrumentation settings used for transtympanic (TT-ECOG) and extratympanic electrocochleography (ET-ECOG). There is wide variation with regard to the applied stimulus, the settings and interpretation of ECOG results. For most physicians, the presence of endolymphatic hydrops is indicated either by the summating/action potential (SP/AP) ratio for click stimuli or the SP amplitude after tone bursts. Different upper limits have been proposed to discriminate hydropic from non-hydropic ears. Based upon a meta-analysis and classification criteria obtained from multivariate statistics, the authors propose that an SP/AP ratio with click stimulation >0.35 using TT-ECOG, or >0.42 using ET-ECOG, is indicative of hydrops. With tone burst stimulation set at a repetition rate of 30–40 stimuli per second, a SP of < -2 μV using TT-ECOG for at least one frequency within the range 0.5–8.0 kHz is considered pathologic.

Key Words:

• electrocochleography
• endolymphatic hydrops
• meta-analysis
• instrumentation settings