方向感検査による小脳橋角部腫ようの早期診断

Abstract

The authors report 22 patients with cerebello-pontine angle lesions: 15 with acoustic tumors and 7 with menigiomas, epidermoids or trigeminal neurinomas. Nearly all showed close to normal or only slightly impaired hearing threshold levels on their audiograms.All patients received the full battery of directional hearing tests, speech audiometry, acoustic reflex threshold, and decay test, ENG and caloric test, and ABR test. Finally, they received CT scanning or MRI tests, and cerebello-pontine angle lesions were confirmed.Twenty patients (91%) had very positive findings, especially increased thresholds of interaural time discrimination in the directional hearing tests. This test has good sensitivity for retrocochlear lesions; it is very simple and needs only a few minutes to perform. The authors conclude that this test provides the most useful information in the early diagnosis of cerebello-pontine angle tumors, as a screening test.We present a flow-chart of the battery of tests in which the directional hearing test is performed in the early stage of test procedures.