ENT Clinic, Münster University Hospital, Münster, Germany.
Ear Hear. 2013 May-Jun;34(3):370-84. doi: 10.1097/AUD.0b013e31826d0c08.
Nearly half a century ago, administration of glycerol was shown to temporarily improve the threshold of hearing in patients with suspected Menière's disease (glycerol test). Although a positive test result provides strong evidence of Menière's disease, the test has not gained widespread acceptance. A probable reason is that there is no consensus as to the definition of positive. Moreover, a negative test result is of little diagnostic value because Menière's disease cannot be excluded. By reanalyzing archived data, the authors sought to understand the test in light of signal detection theory. Moreover, they explored the possibility of estimating the probability of a positive test result from the pretest audiogram.
The study is based on audiograms from 347 patients (356 ears) who underwent a glycerol test to corroborate a suspected diagnosis of Menière's disease. Subsequent to an initial pure-tone audiogram, glycerol (1.2 mL/kg body weight) was orally administered; follow-up audiograms were obtained after 1, 2, 3, and 4 hr. Transcription of the audiograms into a computer-readable form made them available for automated reanalysis.
Averaged difference audiograms provided detailed insight into the frequency dependence and the temporal dynamics of the glycerol-induced threshold reduction. The strongest threshold reduction was observed 4 hr after glycerol intake, although nearly the same effect was already found after 3 hr. Strong overall threshold reductions were associated with a pronounced maximum at approximately 1000 Hz; weaker effects were associated with a plateau between 125 and 1000 Hz and a rapid decrease toward higher frequencies. To date, criteria suggested for a positive test result vastly differ in both sensitivity (with regard to the detection of a threshold reduction) and specificity (1 minus false-positive rate). Here, a criterion based on the aggregate threshold reduction in adjacent audiometric frequencies is suggested. This approach does not only seem to be more robust but also permits to freely adjust the false-positive rate. A positive test result is particularly likely when the mean low-frequency hearing loss is approximately 60 dB and the mean high-frequency hearing loss does not exceed 50 dB.
If the pretest audiogram does not render a positive test result unlikely, a state-of-the-art implementation of the glycerol test is a competitive method for corroborating a suspected diagnosis of Menière's disease.
近半个世纪前，人们发现甘油给药可暂时提高疑似梅尼埃病（甘油试验）患者的听力阈值。虽然阳性试验结果为梅尼埃病提供了有力的证据，但该试验并未得到广泛认可。一个可能的原因是，对于阳性的定义尚未达成共识。此外，阴性试验结果的诊断价值不大，因为不能排除梅尼埃病。通过重新分析存档数据，作者试图根据信号检测理论来了解该试验。此外，他们还探讨了从预测试听力图估计阳性试验结果概率的可能性。
本研究基于 347 名（356 耳）接受甘油试验以证实疑似梅尼埃病诊断的患者的听力图。初始纯音听力图后，口服甘油（1.2mL/kg 体重）；1、2、3 和 4 小时后获得随访听力图。将听力图转录为计算机可读形式，使其可进行自动重新分析。
平均差异听力图详细说明了甘油引起的阈值降低的频率依赖性和时间动态。甘油摄入后 4 小时观察到最强的阈值降低，尽管在 3 小时后已发现几乎相同的效果。整体阈值的强烈降低与大约 1000Hz 处的明显最大值相关；较弱的效果与 125Hz 至 1000Hz 之间的平台和向更高频率的快速下降相关。迄今为止，对于阳性试验结果的建议标准在灵敏度（与检测阈值降低相关）和特异性（1 减去假阳性率）方面差异很大。此处，建议基于相邻听力计频率的总阈值降低的标准。这种方法不仅似乎更稳健，而且还允许自由调整假阳性率。当低频听力损失平均值约为 60dB，高频听力损失平均值不超过 50dB 时，阳性试验结果特别可能。
如果预测试听力图不太可能显示阳性试验结果，则最先进的甘油试验实施是证实疑似梅尼埃病诊断的一种有竞争力的方法。
