Evaluation of Diagnostic Audiometric Tests

Abstract

Five diagnostic audiometric procedures.sbd.acoustic reflexes, performance-intensity functions for monosyllabic (phonetically balanced) words, Bekesy audiometry, Bekesy comfortable loudness audiometry and suprathreshold adaptation test.sbd.were critically evaluated by decision matrix analysis and information theory analysis. Patients (20) with surgically confirmed 8th nerve disorders and patients (20) with presumed cochlear disorders were studied. Each patient completed all test procedures. In terms of decision matrix analysis, sensitivity (correct identification of 8th nerve site) ranged from 45-85%. Specificity (correct rejection of patients with cochlear site) ranged from 70-100%. Predictive value ranged from 74-100% for positive results and from 62-82% for negative results. The efficiency of the 5 tests ranged from 68-78%. In terms of information theory, positive test results increased the probability of 8th nerve disorder in any subject from 50% (a priori) to 74-100%. Negative test results decreased the probability of 8th nerve disorder from 50% to 18-38%. Relative differences among the diagnostic effectiveness of the 5 individual test procedures were not pronounced. The suprathreshold adaptation test (results confined to 500, 1000 and 2000 Hz) was less efficient than the other 4 diagnostic techniques.