Comment on the Distorted Speech Test

Abstract

Distorted speech tests were performed to 10 normal subjects and to 50 patients sufferring from various kinds of hearing disturbance according to following battery of presentation of speech sounds.1. Non- distorted speech sounds.2. 1200Hz low pass filtered speech sounds.3. 1700Hz high pass filtered speech sounds.4. Monaurally mixed speech sounds of 1200Hz low pass and 1700Hz high pass filtered speech. (1200-1700Hz band eliminated filtered speech sounds.)5. 1200-2400Hz band pass filtered speech sounds.To judge the results of these tests three methods were considered. The first was termed articulation method that the abnormality was judged by the articulation score of distorted speech sounds, the second was subtraction method which was judged by the difference between articulation score of non-distorted and of distorted speech sounds, and the third was division method which was judged by the ratio of the articulation score of distorted speech sounds to that of non-distorted speech sounds.Those who were judged as normal by the articulation method but as abnormal by the other methods were very rare, and were able to be found only among those who showed an articulation score of 90% or more in the non-distorted speech test.The authors considered to make simple the distorted speech tests, and concluded that both low pass filtered speech test and high pass filtered test were to be performed at least, otherwise the merit of the distorted speech test would decrease, because omitted cases would increase.