Improved sensitivity of electrocochleography in the diagnosis of Meniere's disease

Abstract

Abstract

ECochG has long been shown to complement the diagnosis of MD, primarily through measurement of the SP/AP amplitude ratio. While reported in the literature to be highly specific to this disorder, ECochG's sensitivity in the general MD population remains relatively low (ranging from 20–65%). The current study assessed the sensitivity and specificity of the ECochG protocol we employ for suspected MD patients, which includes measuring both the amplitudes and areas of the SP and AP to clicks (to derive the SP/AP amplitude and area ratios), and the SP amplitudes to 1000 and 2000 Hz tone bursts. A retrospective chart review was conducted to compare ECochG results from 178 suspected MD patients with their eventual diagnoses. Measurements of highest sensitivity and specificity (determined using a logistic regression analysis) included: SP amplitude, SP area, SP/AP area ratio, and total SP-AP area. Sensitivity and specificity values associated with these measures were 92% and 84%, respectively. The sensitivity value is considerably higher than previously reported, and is attributable to the inclusion of area measurements in our protocol.

Sumario

La ECochG ha demostrado ser complementaria en el diagnóstico de la enfermedad de Meniere (MD) principalmente medi-ante la medición de la amplitud del ratio SP/AP. Mientras que se ha reportado en la literatura la alta especificidad de la ECochG, su sensibilidad en la población general con MD permanece relativamente baja (en un rango del 20 al 65%). Este estudio evalúa la sensibilidad y la especificidad del protocolo de ECochG que empleamos en pacientes con sospecha de MD, el cual incluye la medición tanto de la amplitud y las áreas de SP y AP con clics (para derivar los ratios de área y amplitud SP/AP), y las amplitudes de SP con burst tonales de 1000 y 2000Hz. Se construyó una tabla retrospectiva para comparar los resultados de ECochG de 178 pacientes con sospecha de MD, con sus diagnósticos eventuales. Las mediciones de la más alta sensibilidad y especificidad (determinadas mediante un análisis de regresión logística) incluyeron: amplitud SP, área SP, ratio de área SP/AP y área total SP-AP. La sensibilidad y la especificidad asociadas con estas mediciones fueron 92% y 84% respectivamente. El valor de sensibilidad es considerable-mente mayor que el previamente reportado y se atribuye a la inclusión de la medición del área en nuestro protocolo.

Key Words:

• Electrocochleography
• Meniere's disease
• Summating potential
• Action potential
• Specificity
• Sensitivity

Acknowledgement

Preliminary data from portions of this study were presented at the 2007 annual meeting of the American Auditory Society in Phoenix, Arizona (March), the 2007 Annual Convention of the American Academy of Audiology in Denver, Colorado (April), and the 2008 meeting of the International Congress of Audiology in Hong Kong, China (June). The authors extend their gratitude to Dr. John Durrant for his consultation on the preparation of this manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.