Razza Sergio, Burdo Sandro
Servizio di Audiovestibologia, Ospedale di Circolo, Varese, Italy.
Cochlear Implants Int. 2011 May;12(2):114-23. doi: 10.1179/146701010X486499.
To describe the rate of occurrence of unsuspected decrease in sensitivity of the sound processor microphone and to evaluate its effect on the patient's audiological performance in terms of reduction in speech recognition scores.
Speech processor microphones were tested by connecting the speech processor acoustic monitor circuit to a hearing aid analyzer. The response curves were compared with those obtained from fully working microphones. During a 6-month investigation period, microphone response curves were measured from a group of cochlear implant recipients who had not reported any problems. Despite the absence of any subjective problem, some microphones were found to show a loss of sensitivity. Their users, aged between 4 and 67 years, were tested both with the defective and a working microphone in order to calculate the correlation between the degree of microphone failure and the decline in audiological performance. To quantify the effect of microphone failure, patients' speech recognition skills were measured by live voice connected discourse tracking series administered in different conditions and by recorded sentences lists.
A total of 120 apparently fully functioning sound processors were tested in the investigation: 33 (27.5%) were affected by a subjectively unreported sensitivity decrease. Speech-tracking scores correlated significantly with the loss of microphone sensitivity in all test conditions (r = 0.69-0.77, P < 0.05). A high degree of correlation was also found for speech audiometry tests (r = 0.70-0.73, P < 0.05). Microphone sensitivity loss affected speech recognition skills, especially without lip reading and in the presence of background noise.
The results indicate that any reduction in sound processor microphone sensitivity causes a degree of hearing decline that negatively affects the cochlear recipient's clinical performance. Microphone faults are often unreported events, and their occurrence rate is underestimated. To establish that the microphone is providing correct input to the speech processor a standard control procedure, including technical and clinical checks, is needed in clinical practice.
描述声音处理器麦克风灵敏度意外下降的发生率，并根据言语识别分数的降低来评估其对患者听力学表现的影响。
通过将言语处理器声学监测电路连接到助听器分析仪来测试言语处理器麦克风。将响应曲线与从完全正常工作的麦克风获得的曲线进行比较。在为期6个月的调查期内，从一组未报告任何问题的人工耳蜗植入受者中测量麦克风响应曲线。尽管没有任何主观问题，但发现一些麦克风显示出灵敏度损失。对年龄在4至67岁之间的使用者，分别使用有故障的麦克风和正常工作的麦克风进行测试，以计算麦克风故障程度与听力学表现下降之间的相关性。为了量化麦克风故障的影响，通过在不同条件下进行的实时语音连接话语跟踪系列以及录制的句子列表来测量患者的言语识别技能。
在调查中总共测试了120个表面上功能完全正常的声音处理器：33个（27.5%）受到主观未报告的灵敏度下降的影响。在所有测试条件下，言语跟踪分数与麦克风灵敏度损失显著相关（r = 0.69 - 0.77，P < 0.05）。言语听力测试也发现了高度相关性（r = 0.70 - 0.73，P < 0.05）。麦克风灵敏度损失影响言语识别技能，尤其是在没有唇读和存在背景噪声的情况下。
结果表明，声音处理器麦克风灵敏度的任何降低都会导致一定程度的听力下降，对人工耳蜗植入受者的临床表现产生负面影响。麦克风故障通常是未报告的事件，其发生率被低估。在临床实践中，需要一个标准的控制程序，包括技术和临床检查，以确定麦克风是否向言语处理器提供正确的输入。
