Hosoda Y, Ushiro K, Doi T, Kumazawa T
Department of Otolaryngology, Kansai Medical University, Osaka, Japan.
Acta Otolaryngol Suppl. 1993;500:23-5. doi: 10.3109/00016489309126172.
To determine whether tinnitus has a masking effect similar to that of general external sounds, the hearing threshold shift when the tinnitus was changed by intravenous administration of lidocaine was measured by contingent negative variation (CNV) audiometry. In a preliminary study, the reliability of CNV audiometry was evaluated in 12 patients with tinnitus. The reproducibility of CNV audiometry was confirmed, based on repeated measurements of CNV audiometry at the tinnitus frequency. The threshold difference between CNV audiometry and pure tone audiometry was -0.76 +/- 1.35 dB, and a high statistical correlation between the threshold of CNV audiometry and pure tone audiometry was evident. The CNV threshold shift at tinnitus frequency after lidocaine injection was measured in 89 ears. In the tinnitus-decreased group, the CNV threshold decreased (4-6 dB) in 22% of cases; however, in the tinnitus-unchanged group, the CNV threshold was little changed. These findings suggest that tinnitus may have a masking effect as is the case with external sounds.
为了确定耳鸣是否具有与一般外界声音类似的掩蔽效应，通过关联负变化（CNV）听力测定法测量静脉注射利多卡因改变耳鸣时的听力阈值变化。在一项初步研究中，对12例耳鸣患者评估了CNV听力测定法的可靠性。基于在耳鸣频率下对CNV听力测定法的重复测量，证实了CNV听力测定法的可重复性。CNV听力测定法与纯音听力测定法之间的阈值差异为-0.76±1.35dB，并且CNV听力测定法的阈值与纯音听力测定法之间存在高度统计学相关性。对89只耳朵测量了注射利多卡因后耳鸣频率下的CNV阈值变化。在耳鸣减轻组中，22%的病例中CNV阈值下降（4-6dB）；然而，在耳鸣未改变组中，CNV阈值几乎没有变化。这些发现表明，耳鸣可能具有与外界声音一样的掩蔽效应。
