ECochG Atlas · Print-friendly overview
All modules at a glance
One-page summary of all fourteen ECochG Atlas modules with level tags, standfirst paragraphs, and the section table-of-contents per module. Use the print button below to generate a portable PDF reference, or click through to the full interactive module pages. The companion /glossary, /references, and /progress pages live separately.
Electrocochleography is the oldest of the clinical auditory evoked potentials. This module sets out what the test measures, a short history from Fromm 1935 to Campbell 2022, and the F/T/C reader-level scheme.
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The cochlear biology underneath everything else in the atlas — hair cells, ribbon synapses, the endocochlear potential, and the geometry that determines which generators contribute to which recorded potential.
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A clean ECochG trace is the product of three deliberate choices: where the electrode sits, what stimulus you deliver, and how you filter and average what comes back.
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What a normal click-evoked ECochG looks like, how the latency-intensity function separates conductive, cochlear, and retrocochlear patterns, and how click rate affects the AP.
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The biggest clinical use of ECochG, and the most debated. An elevated SP/AP ratio is the canonical signature of endolymphatic hydrops — but the test misses 30–50% of patients.
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A bony defect over the superior semicircular canal creates a third window that elevates SP/AP and mimics Ménière's disease on ECochG. Telling them apart is the diagnostic point.
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ECochG at its most pathognomonic. Outer hair cells working — CM present, inverts with polarity. Auditory nerve transmission failed — CAP absent. The Berlin polarity-reversal protocol separates real biology from stimulus artifact.
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Acute SNHL ≥ 30 dB across three contiguous frequencies in < 72 h. 71–90% are idiopathic; ECochG's role in distinguishing the rest is now small — MRI or ABR per the 2019 AAO-HNSF guideline.
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Fifty years of controversy. ECochG with intra-test postural manoeuvres (Gibson 1992) is one of the few functional tests for an active fistula. CTP biochemical assay is the modern alternative where available.
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The poster condition for why ECochG cannot replace imaging. The AP generator sits peripheral to where most schwannomas arise, so a deceptively normal ECochG never excludes a tumour — gadolinium-enhanced MRI does.
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A patient with a normal audiogram who cannot follow speech in noise. The animal data are unambiguous; the human translation is contested. What is known, what is hoped, what remains a research question.
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The growth area of clinical ECochG, and the only one with randomised trial evidence. Real-time monitoring of the CM via the implant's own electrodes; Campbell 2022 RCT-defined ≥30% drop trigger preserves residual hearing.
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ECochG and ABR are not competing tests. The AP of ECochG is the same physiological event as wave I of the ABR. Used together, the two tests cover the entire peripheral auditory pathway from hair cell to upper brainstem.
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Practical infrastructure: a working SP/AP calculator that applies all the cutoffs from the disease modules, plus links to the glossary, references, and progress dashboard.
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