Evaluation of the threshold tone decay test. I. On the test

Abstract

Threshold tone decay (T.TD.) test was evalu-ated, and also it was compared with various kinds of recruitment tests, in order to understand the clinical significance of T.T.D. Test.It was found, that the appearance of T.T.D. was not changed when the test was repeated or even when the threshold value changed. It takes only one minuite to perform the test and T.T.D. was not overlooked if the test was done on the sounds of 4KC and 8KC.Based on the above results, T.T.D. Test was performed in subjects with various kinds of dea-fness. Phenomenon of T.T.D. was mainly noticed in subjects of hair cell disorders such as Meniere's disease and noise deafness. In Meniere's disease, T.T.D. appeared more markedly in the attacking phase than in the resting phase. However, marked on can not be determined only by the presence of T.T.D. It is, however, apparent that the subje-cts of hair cells disease showed T.T.D. most frequ-ently. Further study is necessary for its final interpretation.On comparing T.T.D. Test with various recru-itment tests, it can be said that no constant relationship between these tests was found. This is because T.T.D. does not appeare only in a definite site of lesion, the interpretation of various recruitment tests has not been well established and because, as clinical cases seem to have complex lesions, even in the cases which were diagnosed as cochlear lesion, the central or conductive lesions may be included in part, and so the manifestations of these associated lesions may be thought to appear ment tests. At preset, T.T.D. Test or other recruit-ment testsAt preset, T.T.D. Test and other recruitment tests are performed in various combinations and the results of these test should be interpreted to make the diagnosis.