The Audiologic Evaluation of Cerebellopontine Angle Tumor Suspects: A Review of Tumor and Non-Tumor Suspects

Abstract

In an initial study from January 1981 through December 1983, audiologic data were gathered on 41 patients with proven cerebellopontine angle (CPA) tumors and 82 tumor suspects who revealed no tumor on computed tomography with air cisternography of the internal auditory canal. The acoustic reflex threshold and decay, performance intensity function for phonetically balanced (PB) words, and several auditory brainstem response (ABR) variables were examined. Sensitivity, specificity, and diagnostic efficiency were calculated for each test. The ABR was better than the other tests. The interaural wave V latency difference (IT5) had a sensitivity of 100%, specificity of 80%, and diagnostic efficiency of 87%. In a subsequent study, from January 1984 to June 1985,52 patients with abnormal IT5 values were examined to determine the predictive value of a positive IT5 in detection of a CPA tumor. Nineteen of these patients had CPA tumors, for a detection rate of 36%. The high diagnostic efficiency of the ABR, coupled with the prevalence of a CPA tumor in a tumor suspect population, will translate into a yield of approximately one tumor for every three abnormal IT5 tests.