AMTAS^®: Automated method for testing auditory sensitivity: III. Sensorineural hearing loss and air-bone gaps

Abstract

Abstract

Objective: The objectives were to measure the occlusion effect produced by three earphones—circumaural, supra-aural, and insert—and to compare air- and bone-conduction thresholds obtained with manual and automated methods for subjects with sensorineural hearing loss. Design: Acoustic and psychoacoustic occlusion effects were measured with each earphone. Manual and automated, air- and bone-conduction thresholds were compared. Study sample: Occlusion effects were measured for six adult subjects with normal external and middle ears. Pure-tone thresholds were measured for nineteen ears of thirteen subjects with sensorineural hearing loss. Results: The supra-aural earphone produced the largest occlusion effects, followed by the insert and circumaural earphones. Some systematic differences in air-conduction thresholds were found for the two procedures that may be attributable to earphone differences. A large air-bone gap at 4 kHz, reported in a previous study, was replicated. Conclusions: From 0.5 to 8.0 kHz, occlusion effects produced by the circumaural earphone are sufficiently small that covering the ear does not appreciably alter bone-conduction thresholds. Air-conduction threshold differences warrant further study to determine if reference equivalent threshold sound pressure levels for the two earphones produce equivalent thresholds. The large air-bone gap at 4 kHz suggests the possibility of an incorrect reference equivalent threshold force level at that frequency.

Sumario

Objetivo: Los objetivos fueron medir el efecto de oclusión producido por tres auriculares – circumaural, supra-aural y de inserción – y comparar umbrales de conducción aérea y ósea obtenidos con métodos manuales y automatizados para sujetos con hipoacusia sensorineural. Diseño: Se midieron los efectos de oclusión acústicos y psicoacústicos con cada auricular. Se compararon los umbrales de conducción aérea y ósea manuales y automatizados. Muestra del Estudio: Se midieron los efectos de oclusión para seis sujetos adultos con oídos externos y medios normales. Resultados: Los auriculares supra-aurales produjeron los mayores efectos de oclusión, seguidos de los auriculares de inserción y los circumaurales. Se encontraron algunas diferencias sistemáticas en los umbrales de conducción aérea para los dos procedimientos que pueden atribuirse a las diferencias en los auriculares. Una gran brecha aéreo-ósea en 4 kHz que se reportó en un estudio previo, fue replicada. Conclusiones: De 0.5 a 8 kHz, los efectos de oclusión producidos por los auriculares circumaurales son lo suficientemente pequeños por lo que cubrir el cubrir el oído no altera apreciablemente los umbrales de conducción ósea. Las diferencias en los umbrales de conducción aérea exigen estudios adicionales para determinar si los niveles umbrales equivalentes de referencia de presión sonora para los dos auriculares producen umbrales equivalentes. La mayor brecha aéreo-ósea en 4 kHz sugiere la posibilidad de un nivel de referencia equivalente de fuerza umbral en esa frecuencia.

Key Words::

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

Acknowledgements

This research was supported by grant R42 DC007773 from the National Institutes of Health. We are grateful to research audiologist Allison Kohtz for collecting the data presented in this report, and to three anonymous reviewers for their helpful suggestions. AMTAS^® intellectual property is owned by the first author and Audiology Incorporated, and may become a commercial product. Author BM was supported by the MRC (UK).

Declaration of interest: The first author declares a conflict of interest that is disclosed in the Acknowledgements section. The second author reports no conflicts of interest. The authors alone are responsible for the content and writing of the paper.