AMTAS^®: Automated method for testing auditory sensitivity: Validation studies

Abstract

Abstract

Three studies are reported assessing the validity of AMTAS^®, an automated method for obtaining an audiogram, including air- and bone-conduction thresholds (stimuli delivered by a forehead-placed transducer) with masking noise presented to the non-test ear. In Study 1, six subjects at each of three sites were tested using manual audiometry by two audiologists at each site. The mean differences between the audiograms for the paired audiologists provided a measure of the reliability of traditional audiometry. In Study 2, thirty subjects (5 normal hearing, 25 hearing impaired) were tested using AMTAS and manual audiometry. For air-conduction thresholds, AMTAS-manual differences were similar to inter-tester differences in Study 1, but for bone-conduction thresholds, the former were larger. Two possible sources of the greater differences were identified, (1) incorrect reference-equivalent threshold force levels for forehead bone conduction, and (2) a differential effect of middle-ear disease on forehead and mastoid bone-conduction thresholds. In Study 3, intersubject variability was studied for forehead and mastoid bone-conduction thresholds. The results indicate similar variability for the two placement sites.

Sumario

Se han reportado tres estudios que evalúan la validez del AMTAS^®, un métodos automatizado para obtener un audio-grama, incluyendo umbrales de conducción aérea y ósea (los estímulos se realizan por un transductor colocado en la frente) con ruido de enmascaramiento presentado al oído no evaluado. En el Estudio 1, se evaluó a seis sujetos en cada uno de los tres sitios, usando audiometría manual realizada por dos audiólogos en cada sitio. Las diferencias medias entre los audiogramas para estos audiólogos mostraron una medida de la confiabilidad de la audiometría tradicional. En el Estudio 2, se evaluaron treinta sujetos (cinco con audición normal y 25 con hipoacusia) utilizando AMTAS y la audiometría manual. Para los umbrales de conducción aérea, las diferencias AMTAS-manual fueron similares a las diferencias entre evaluadores en el Estudio 1, pero para los umbrales de conducción ósea, las últimas fueron mayores. Se identificaron dos posibles fuentes para estas diferencias mayores, (1) niveles umbrales de fuerza de referencia equivalente incorrectos para la conducción ósea en la frente, y (2) un efecto diferencial para los umbrales de conducción ósea sobre la frente y el mastoides debido a enfermedad del oído medio. En el Estudio 3, se estudió la variabilidad entre sujetos para los umbrales de conducción ósea en la frente y en el hueso mastoides. Los resultados indican similar variabilidad para los dos sitios de colocación.

Key words::

• Audiometry
• Automated audiometry
• Hearing
• Hearing test
• Air conduction
• Bone conduction
• Threshold

Acknowledgements

Study 1 was supported by the National Institutes of Health Small Business Technology Transfer Program (Grant No. R42 DC005110). Lisa Hunter and Richard Wilson were valuable collaborators on that project. We are grateful to GN Otometrics and particularly to Peter Kossek for support of Study 2 and to David Baguley at Addenbrooke’s Hospital for assistance in recruiting subjects. Bruce Lindgren provided essential guidance for statistical analysis. Three anonymous reviewers provided very helpful suggestions that improved the manuscript. AMTAS^® intellectual property is owned by the first author and Audiology Incorporated and may become a commercial product.

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