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Study of cochlear microphonic potentials in auditory neuropathy.
Ilka do Amaral Soares1, Pedro de Lemos Menezes2, Aline Tenório Lins Carnaúba3
1Universidade Federal de São Paulo (UNIFESP), Ciências Médicas, São Paulo, SP, Brazil; Universidade Estadual de Ciências da Saúde de Alagoas, Maceió, AL, Brazil.
Brazilian Journal of Otorhinolaryngology
|May 15, 2016
Summary
Cochlear Microphonic Potential is key for diagnosing Auditory Neuropathy/Dyssynchrony. This review highlights its diagnostic importance and optimal measurement protocols for accurate results in patients with this condition.
Area of Science:
- Audiology
- Neuroscience
- Otolaryngology
Background:
- Auditory Neuropathy/Dyssynchrony (AN/AD) is characterized by specific electrophysiological findings, including present Otoacoustic Emissions and Cochlear Microphonic Potentials.
- A key diagnostic feature of AN/AD is the absence or severe alteration of Brainstem Evoked Auditory Potential, with auditory thresholds incongruent with speech perception.
- The Cochlear Microphonic Potential (CMP) is considered a crucial tool for the accurate diagnosis of AN/AD.
Purpose of the Study:
- To characterize the Cochlear Microphonic Potential in individuals with Auditory Neuropathy/Dyssynchrony.
- To conduct an integrative review of existing literature on CMP in AN/AD.
Main Methods:
- A comprehensive bibliographic survey was conducted on major scientific databases (PubMed, Bireme, MedLine, LILACS, SciELO) up to July 2014.
- Studies were selected based on predefined criteria, including author, year, evidence level, objective, sample characteristics, and methodologies.
- A total of 14 relevant articles were selected for the review after an initial screening of 1959 articles.
Main Results:
- The amplitude of the Cochlear Microphonic in individuals with AN/AD did not significantly differ from that of normal-hearing individuals.
- A notable finding was that the duration of the Cochlear Microphonic was observed to be longer in individuals diagnosed with AN/AD.
- The review identified specific protocols for CMP determination, emphasizing the use of insert earphones, reverse polarity, and stimulus tube blocking to mitigate electrical artifacts.
Conclusions:
- The presence of the Cochlear Microphonic is a definitive indicator in the differential diagnosis of Auditory Neuropathy/Dyssynchrony.
- Optimized protocols for CMP measurement, including specific equipment and techniques, are essential for reliable diagnosis.
- Understanding CMP characteristics, such as duration, aids in differentiating AN/AD from other auditory disorders.
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