Sardari Sara, Jafari Zahra, Haghani Hamid, Talebi Hossain
Department of Audiology, Faculty of Rehabilitation, Tehran University of Medical Sciences, Iran.
Department of Basic Sciences in Rehabilitation, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran; Canadian Center for Behavioral Neuroscience (CCBN), Lethbridge University, Lethbridge, Alberta, Canada.
Hear Res. 2015 Dec;330(Pt A):134-41. doi: 10.1016/j.heares.2015.09.004. Epub 2015 Sep 16.
Aided thresholds can be used for prediction of success of hearing aids and to choose between hearing aids and cochlear implants. This study aimed to compare characteristics of aided and unaided auditory steady-state responses (ASSRs).
A total of 30 moderate to profoundly hearing-impaired subjects participated in this study. The subjects underwent acoustic immittance, behavioral audiometry, and ASSR with the modulation rate of 40 Hz, first without a hearing aid and then with a hearing aid. Sixteen people with normal hearing and 17 people with severe hearing loss were included in biological calibration of the sound field.
There was a significant difference between unaided behavioral and ASSR thresholds in all test frequencies (mean difference of unaided behavioral ASSR thresholds: 6.19 dB; P = 0.02 at 500 Hz, P < 0.001 at 1000 and 2000 Hz, and P = 0.02 for 4000 Hz). There was also a significant difference between aided behavioral and ASSR thresholds at 1000 and 2000 Hz (P < 0.001) but not at 500 (P = 0.14) and 4000 (P = 0.23) Hz (mean difference of behavioral ASSR thresholds was 4.33 dB). Despite observing any unaided responses, aided thresholds could be recorded in some severe to profoundly hearing-impaired subjects. The number of recordable thresholds was directly related to speech clarity and speech-reading ability. Multi-frequency stimulation elevated the ASSR threshold, especially for the higher frequencies and in the aided condition.
Functional and ASSR gains show less difference than threshold data. Therefore, comparing gains instead of thresholds is more accurate for validation of hearing aids. The probability of success of hearing aids appears to be poor if ASSRs (especially aided ones) cannot be recorded. If special care is taken in the fitting of hearing aids and the testing conditions, aided ASSR testing could be a useful tool for validation of hearing aids and the cochlear implant decision-making process.
助听阈值可用于预测助听器的使用效果，并在助听器与人工耳蜗之间进行选择。本研究旨在比较助听和无助听状态下听觉稳态反应（ASSR）的特征。
共有30名中度至重度听力受损受试者参与本研究。受试者先在不佩戴助听器的情况下，然后佩戴助听器进行声导抗、行为测听以及调制率为40Hz的ASSR测试。16名听力正常者和17名重度听力损失者纳入声场生物校准。
在所有测试频率下，无助听行为阈值与ASSR阈值之间均存在显著差异（无助听行为ASSR阈值的平均差异：6.19dB；500Hz时P = 0.02，1000Hz和2000Hz时P < 0.001，4000Hz时P = 0.02）。在1000Hz和2000Hz时，助听行为阈值与ASSR阈值之间也存在显著差异（P < 0.001），但在500Hz（P = 0.14）和4000Hz（P = 0.23）时无显著差异（行为ASSR阈值的平均差异为4.33dB）。尽管在一些重度至极重度听力受损受试者中未观察到无助听反应，但仍可记录到助听阈值。可记录阈值的数量与言语清晰度和言语阅读能力直接相关。多频刺激会提高ASSR阈值，尤其是在高频和助听条件下。
功能增益和ASSR增益的差异比阈值数据小。因此，比较增益而非阈值对助听器验证更为准确。如果无法记录ASSR（尤其是助听ASSR），助听器成功使用的可能性似乎较低。如果在助听器验配和测试条件上特别注意，助听ASSR测试可能是验证助听器和人工耳蜗决策过程的有用工具。
