gms | German Medical Science

85th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

28.05. - 01.06.2014, Dortmund

The efficiency of different ERA methods for objective hearing threshold estimation in low frequency range

Meeting Abstract

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 85th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Dortmund, 28.05.-01.06.2014. Düsseldorf: German Medical Science GMS Publishing House; 2014. Doc14hno12

doi: 10.3205/14hno12, urn:nbn:de:0183-14hno120

Published: July 24, 2014

© 2014 Zeidler et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Introduction: With the establishment of newborn hearing screening in Germany in 2009 methods for objective hearing threshold estimation obtained more relevancy. Several brainstem evoked response audiometry (BERA)-methods have been established in clinical routine for hearing threshold estimation. The Click-BERA forms the gold standard in main speech range. It lacks of a reliable for objective hearing threshold estimation in the low frequency range. Furthermore, the different the test results of the different BERA methods are hardly comparable due to methodological aspects. It is of great relevance to define a universal standard of comparison that is independent from audiometric measurement categories. For this purpose Hoth proposed to use the turning point of the increase of the discriminationfunction of the respective BERA method [1].

Methods: 25 normal hearing adults between 18 and 30 years were analyzed. The hearing threshold estimation at 500 Hz was performed with five different methods allowing an investigation in the low frequency domain (low-chirp BERA (LCBERA), notched-noise BERA (NNBERA), narrow band CE-chirp BERA (NBCBERA), narrow band CE-chirp ASSR (NBCASSR) (40 Hz and 90 Hz)). The measurements started with 40 dB, were decreased to the hearing threshold and stopped, if possible, 20 dB below the hearing threshold. If there was no stimulus answer at 40 dB, the sound pressure was raised up until the detection of a threshold. The sound pressure level varied in 5 dB steps until a sound pressure level related series of numbers (0=no answer, 1=answer) was gained. The discrimination function, its increase, and the turning point as correlate of the efficiency of each BERA method were calculated.

Results: The increase at the turning point was 4.1%/dB for NNBERA, 3,2 percent/dB for NBCBERA, 8,6 percent/dB for LCBERA 6.4%/dB, for NBCASSR (40 Hz) and 3.6%/dB for NBCASSR (90 Hz).

Discussion: LCBERA detected the hearing threshold in low frequency range most exactly. But LCBERA contained a larger frequency spectrum than NNBERA. Nevertheless, we favor LCBERA as method of choice because of its more exact detection rate.

Conclusion: The use of the discrimination function seems to be valid to evaluate the efficiency of different BERA methods. The tested methods show large differences in their quality. The LCBERA seems to have the highest efficiency and is recommended for use in clinical routine.


Hoth S. Die Steigung der Diskriminationsfunktion als universelles Maß zur Beurteilung der Güte von Methoden der objektiven Schwellenbestimmung. Z Audiol. 2013;52(2):61-9.