Use of auditory field measurement in patients with otosclerosis

Abstract

Middle ear surgery sometimes leads to unpleasant auditory impressions such as distortion or hyperacusis that cannot be detected by conventional audiometric testing. Sixty-one patients with conductive hearing loss caused by otosclerosis underwent audiological evaluation, which included a questionnaire followed by testing of the audiometric threshold, speech audiometry, and assessment and quantification of loudness perception with a commercial system (WESTRA). This investigation includes the postoperative measurement of hearing improvement and the patients' subjective impressions regarding hearing increase, distortion of speech, and hyperacusis. Hearing improved in 88% of the patients. A quantification of this hearing increase was possible with pure tone audiometry and the Freiburg speech discrimination test. Reduced hearing threshold and lack of improvement in speech discrimination was confirmed by conventional hearing measurements. However, the presence of hyperacusis and distortion of speech could be determined by conventional audiometry in only 50% of cases. It was interesting to note that the subjects who reported speech distortion and hyperacusis in the questionnaire were identified by their increased loudness perception using the categorical loudness scaling. Category loudness scaling appears to be a valuable additional clinical test to characterize postoperative phenomena as distortion of speech and hyperacusis in patients undergoing stapes surgery.