I. Introduction
TRADITIONALLY, a speech discrimination score is the percentage of test items a person can identify correctly by ear. Two decades ago lists of monosyllabic words, the PB-50 tests, were adapted to the measurement of the speech discrimination of the hearing impaired. These materials have since become thoroughly entrenched in otological and audiological practice. unfortunately, a number of confusions regarding their use has persisted to the present. Our purpose is to review some of the factors that contribute to these confusions. The goal is to examine problems which, when kept in mind, can help otologists stabilize measurement of speech discrimination and unify their interpretation of its results.
II. Test Materials
The first problem is, "Which test materials shall one use?"A test of discrimination for speech, as opposed to a threshold test, must consist of relatively nonredundant items. Otherwise, the multiplicity of clues available to the patient will obscure