Knobel Keila Alessandra Baraldi, Sanchez Tanit Ganz
Faculdade de Medicina da Universidade de São Paulo.
Pro Fono. 2006 Jan-Apr;18(1):31-40. doi: 10.1590/s0104-56872006000100005.
Loudness Discomfort Level (LDL), a test used in the hearing aid fitting process, has also been recommended to evaluate patients with tinnitus and/or suspect of hyperacusis.
To determine LDL reference values for normal hearing individuals and to correlate the LDL to the Acoustic Reflex Threshold (ART).
LDL was investigated in 64 normal hearing subjects, with ages between 18 and 25 years (53.1% female), in the frequency threshold of 0.5 to 8KHz and for speech (non-recorded, non-standardized connected discourse). Pulsate pure tones were presented for two seconds, with a one-second interval between each presentation. The initial stimulus intensity was at 50dB and was followed by ascending presentations, of 5dB each, until the subject referred initial discomfort with loudness. The testing procedure was performed separately in each ear, and was immediately repeated at the end of the test (test and retest situation). The choice of the ear that would start the testing procedure was alternated for each subject. After that contralateral acoustic reflexes ART were measured. The presence of the ART was indicated by a minimal needle deflection (larger than 0.05ml) on the emittance equipment.
Median varied from 86 to 98dBHL, with no statistically significant differences between gender (p > 0.11), between ears (p > 0.36) and between the test-retest situation (p > 0.34). The determination coefficients (r2) of the linear regression model revealed absence of correlation between log(LDL) and log(ART).
Normal hearing individuals have LDL between 86 and 98dBHL for all of the tested stimuli. Inter-subject differences and the good reproductivity suggest that the interpretation of the test should be cautious and analyzed considering the patient's history. The test can be an useful instrument go follow-up patients. No correlation was found between LDL and ART.
响度不适阈（LDL）是一种用于助听器验配过程的测试，也被推荐用于评估耳鸣和/或疑似听觉过敏的患者。
确定正常听力个体的LDL参考值，并将LDL与声反射阈值（ART）进行关联。
对64名年龄在18至25岁之间（53.1%为女性）的正常听力受试者进行LDL测试，测试频率范围为0.5至8kHz以及言语（非录制、非标准化连贯话语）。呈现脉冲纯音两秒，每次呈现间隔一秒。初始刺激强度为50dB，随后每次递增5dB进行呈现，直至受试者表示响度最初出现不适。测试程序在每只耳朵分别进行，并在测试结束时立即重复（测试和复测情况）。每个受试者交替选择开始测试程序的耳朵。之后测量对侧声反射ART。ART的存在通过发射设备上最小的针偏转（大于0.05ml）来指示。
中位数在86至98dBHL之间，性别之间（p>0.11）、耳朵之间（p>0.36）以及测试-复测情况之间（p>0.34）均无统计学显著差异。线性回归模型的决定系数（r2）显示log（LDL）与log（ART）之间无相关性。
对于所有测试刺激，正常听力个体的LDL在86至98dBHL之间。个体间差异和良好的重复性表明，测试结果的解释应谨慎，并结合患者病史进行分析。该测试可作为随访患者的有用工具。未发现LDL与ART之间存在相关性。
