Improving the reliability of speech audiometry.

A necessary feature of good recorded speech material is that each list should be identical in respect of graded order of difficulty. Extensive validatory tests have been carried out upon 20 M.R.C. word lists re-recorded by a professional announcer. It can be shown that by various manipulative procedures appreciable improvements may be obtained in the confidence limits of the material. In addition studies have been carried out upon the relationship between Speech Detection Threshold (S.D.T.) Speech Reception Threshold (S.R.T.) and Hearing level (H.L.) in normal hearing subjects. The surprising finding is that both S.D.T. and S.R.T. appear to be relatively independent of H.L. An analysis has been made of the words comprising the material in respect of their ease of recognition and is presented as an appendix.