Comparison of the use of tympanic and extratympanic electrodes for electrocochleography

Authors

  • Ariane Solci Bonucci MD,

    1. Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, University Hospital, Faculty of Medicine of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
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  • Miguel Angelo Hyppolito MD, PhD

    Corresponding author
    1. Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, University Hospital, Faculty of Medicine of Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
    • Divisão de Otorrinolaringologia, Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Monte Alegre, 3900, 14049-900 Ribeirão Preto, SP Brasil
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Abstract

Objectives:

To determine the differences between tympanic and extratympanic electrodes regarding recording technique, comfort and ease of execution of the exam, and quality of auditory potential tracings.

Study Design:

Prospective cross-section investigation.

Methods:

Determination of the summation potential/action potential (SP/AP) ratio by electrocochleography (EchoG) using tympanic and extratympanic electrodes and separate analysis of SP and AP regarding the amplitude recorded.

Results:

Twenty-three subjects (15 men and 8 women; mean age: 33.17 years) with normal tonal threshold audiometry were evaluated. EchoG analysis revealed no significant difference between the two tympanic electrodes. Eleven of the 23 subjects reported discomfort with the insertion of the tympanic electrode even with the use of topical xylocaine, whereas no complaints of discomfort were reported with the use of the extratympanic electrode.

Conclusions:

Both electrodes were effective for EchoG evaluation, but the extratympanic one was easier to insert and did not cause discomfort. However, the tympanic electrode produced tracings of greater amplitude and of better reproducibility. Laryngoscope, 119:563–566, 2009

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