[Influence of disturbing noise on sentence intelligibility (author's transl)].

In the resent paper we tried to get some information on maximal noise level, which permits still some speech perception. As a limit we consider noise levels, where speech perception threshold equals speech level. As long as the difference between speech level and speech perception level is positive, speech perception is more than 50%. The effect of noise level (noise: speech simulating noise) on speech perception (speech material: Marburger Satztest) was investigated in an experimental group of 20 normal hearing persons, 5 patients with highfrequency hearing loss at 1 kHz. The noise levels were: 30, 45, 60 and 75 dBA. In normal hearing people the difference between speech level and speech perception level was positive up to noise levels of 75 dBA; in patients with high-frequency hearing loss at 2 kHz the limit was between 60 and 70 dB, in patients with high-frequency hearing loss at 1 kHz the limit was between 50-60 dB.