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[Sauer's binaural number test in noise. Significance in expertise]
T Braun1, B Leisering, E Krause
1Klinik und Poliklinik für Hals-Nasen-Ohrenheilkunde, Ludwig-Maximilians-Universität, Marchioninistr. 15, 81377, München, Deutschland. thomas.braun@med.uni-muenchen.de
Objective:
For the determination of speech intelligibility in the expertise of hearing loss, the Freiburg speech test (number test and monosyllable test) is recommended in the Federal Republic of Germany. In the former German Democratic Republic, Sauer's binaural number test with 70 dB background noise ("beidohriger Zahlentest", BZT) was a standard element in expert opinions and was used in the calculation of bodily injury ("Körperschaden"). In the current practice, a hearing test in noise is still lacking. The present study analyzes whether and to what degree the impairment ("Grad der Schädigungsfolgen", GdS) changes when also considering Sauer's test.
Material And Methods:
In a collective of 78 patients with hearing loss (66 patients with high-frequency hearing loss and 12 patients with pancochlear hearing loss) and 22 normal hearing controls, the following audiometric measurements were conducted: pure tone audiometry, speech audiometry (Freiburg speech test), free field audiometry with and without noise, and Sauer's test. Subsequently, the hearing loss for both sides was calculated taking into consideration the values obtained with and without Sauer's test, and the respective GdS was determined.
Results:
Patients with high-frequency hearing loss and pancochlear hearing loss had a trend for higher GdS (approximately 2 and 5%, respectively), compared to the established algorithm without the use of hearing tests in noise. However, neither the Mann-Whitney U-test nor the Bland-Altman analysis yielded relevant differences between the two methods to calculate the GdS.
Conclusion:
The routine implementation of Sauer's test in the expertise of hearing loss cannot be recommended, since no relevant change in the GdS can be expected. This is especially true for high-frequency hearing loss. In pancochlear hearing loss, use of Sauer's test can be considered if problems concerning hearing in situations with background noise are present-at least until more advanced hearing tests optimized for use in noise have been integrated into the tables for GdS calculation.
