RECRUITMENT TESTS - A COMPARISON OF CATEG ORY LOUDNESS SCALING AND CONVENTIONAL DIAGNOSTIC AUDIOMETRY

Background: The assessment and localization of hearing impairments req uire reliable and valid recruitment indicators. Although many diagnost ic tests are available, which of these tests are most important is sti ll the subject of controversy. Method: To compare the efficacy of vari ous diagnostic audiometric tests, 51 subjects with monaural sensorineu ral hearing loss were submitted to the following tests at 500 and 2000 Hz: category loudness scaling of narrowband noise bursts, alternate b inaural loudness balance (ABLB), intensity difference limen test, SISI test, fixed frequency Bekesy audiometry, and contralateral determinat ion of the acoustic reflex threshold for pure tones. Results: Using th e findings of the ABLB test as reference, the results of the present s tudy revealed that category loudness scaling and acoustic reflex audio metry are reliable quantitative recruitment indicators. This holds for the intensity difference limen test to a lesser extend as well. Howev er, the recruitment selectivity of the SISI test and the Bekesy audiom etry turned out to be considerably poorer. Conclusions: Category loudn ess scaling has proven to be a valuable element in the conventional re cruitment test battery particularly for patients with symmetrical hear ing loss. Therefore, category loudness scaling, ABLB test (when feasib le), acoustic reflex measurement, and to a lesser extend the intensity difference limen test should be given the highest priority when selec ting appropriate diagnostic audiometric tests. The efficacy of the SIS I test and Bekesy audiometry should be comprehensively reevaluated on the basis of expanded data. Until such material is available and a fin al judgement of the clinical value is possible, both these tests shoul d be used and interpreted carefully.