Studies on the Hearing Test with Speech Sound Part. 1. On the Relations between Pure Tone Hearing, Speech Sound Hearing and Speech Understanding

We have already recognized the necessity of the hearing test with voice as well as pure tone. Speech hearing is influenced not only by the threshold of pure tone hearing and the character of frequencies, but by the character of vowels and consonants forming the speech sounds, and is not necessarily the same as the pure tone hearing. When meaning words are used in the test, mental power works together with the speech sound hearing, resulting in the test of the speech understanding, and not the determination of the true speech hearing. As the result of tests conducted on many cases of hearing difficulty, it was ascertained that pure tone hearing, speech sound hearing and speech understanding do not come to the equal result, and that there exists no definite relation between the results obtained by the above three tests.