Diagnostic Value of the Audiometric Tests in the Acoustic Neuroma / 대한이비인후과학회지

ABSTRACT

BACKGROUND: With the advance of diagnostic technology such as the magnetic resonance imaging, small sized acoustic neuroma has been detected more early and easily. However, the significance of the audiologic examinations could not be ignored because of simplicity of the test procedures as a screening for the acoustic neuroma. OBJECTIVES: This study analyzed the results of preoperative audiologic tests in the surgically confirmed acoustic tumors and compared the diagnostic accuracy and clinical significances. MATERIALS AND METHODS: From May 1990 to April 1997, histopathologically confirmed 26 cases of acoustic neuromas were retrospectively reviewed and analyzed. All the patients were examined pure tone, speech, and auditory brainstem response audiometry. Special audiometric tests for the differential diagnosis of the retrocochlear lesion were performed in selected patents. RESULTS: Tumor size and correlation of the pure tone and speech audiometry were analyzed. The correlations were poor both in pure tone audiometry(p=0.3987 r2=0.03) and speech discrimination score(p=0.3932, r2=0.043). Diagnostic significance of the other audiometric tests showed various results: Suprathreshold adaptation was positive in 5 among 7(71.4%) Roll over phenomenon were showed in 2 among 3 Tone decay test was positive in 4 among 8(50%) Stapedial reflex was decayed in 2 among 5 patients. In the auditory brainstem response(ABR), 16(61.6%) patients showed any waves and 5(19.2%) patients showed only wave I or wave I and II. In five patients(19.2%) showed delayed I-V inter-peak latency. CONCLUSIONS: Among series of the audiologic tests in the acoustic neuroma, ABR was the most valuable diagnostic test and other audiologic tests were showed less sensitivity for the diagnosis of retrocochlear lesion.