Chirp-evoked auditory steady-state responses: Optimal parameters for rapid and objective tests of hearing

在听觉学中，安静条件下可靠的听阈评估方法具有根本的重要性。 对于合作的患者，在听力测试中测量听力图，而对于不合作的患者，例如婴儿，使用听觉诱发电位（AEP）和耳声发射来评估听力能力。特别是从脑电中提取的听觉诱发电位，为安静状态下阈值的测量提供了一种可靠、客观的方法。40多年来，点击诱发的脑干反应（ABR）在临床常规中用于评估安静时在宽频率范围内的平均阈值，但当需要频率特异性估计时，这种刺激类型不是很有用。一种已建立的方法是使用音调脉冲代替滴答声，但对这些刺激的反应对于临床常规来说不够鲁棒，听觉稳态反应（ASSR）是克服上述限制的有希望的工具。ASSR可以在频谱域中进行分析，具有强大的统计测试。从临床角度来看，ASSR可以同时记录多达四个频率和双耳。在过去的几年里，商业实施已经在一些诊所成功使用。这种方法的局限性是，到目前为止，记录相当耗时。这可以通过刺激和记录参数的最佳选择来克服。本研究的目的是调查的影响，刺激和记录参数ASSR的临床高度相关的刺激类型啁啾在多频率设置。啁啾补偿耳蜗中行波的延迟，从而产生大的AEP响应幅度。虽然chirp-evoked ASSR已被应用于临床，但基本刺激和记录参数对chirp-evoked ASSR的影响尚缺乏数据。优化参数的多频啁啾诱发ASSR可能是在临床上对安静时频率特异性阈值进行客观评估的最后一步。刺激和记录参数的影响进行了调查，在成年正常听力的听众和参与者与感音神经性听力损失。这些数据被用作优化参数的基础，以实现稳健有效的临床ASSR记录。

Reliable methods for the assessment of hearing thresholds in quiet are of fundamental importance in audiology. For cooperative patients, the audiogram is measured in hearing tests whereas in non-cooperative patients such as in infants auditory evoked potentials (AEP) and otoacoustic emissions are used to assess the hearing ability. Especially auditory evoked potentials that were extracted from the electroencephalograms provide a robust and objective measure of threshold in quiet. For over 40 years, click-evoked auditory-brainstem responses (ABR) are used in clinical routine for the assessment of an average threshold in quiet over a wide range of frequencies but this stimulus type is not very useful when a frequency-specific estimate is required. An established approach is to use tone pulses instead of clicks but the responses to these stimuli are not robust enough for a clinical routine.Auditory steady state responses (ASSR) are a promising tool to overcome the above mentioned limitations. ASSR can be analysed in the spectral domain with powerful statistical tests. From a clinical perspective, it is useful that ASSR can be recorded for up to four frequencies and in both ears simultaneously. Commercial implementations were already successfully used in some clinics for the past few years. The limitation of this method is, so far, that the recordings are fairly time consuming. This may be overcome by an optimal choice of the stimuli and recording parameters. The aim of the present study is to investigate the impact of stimulus and recording parameters on ASSR for the clinically highly relevant stimulus type chirp in a multi-frequency setting. The chirp compensates for the delay of the traveling wave in the cochlea and thus produces large AEP response amplitudes. Although chirp-evoked ASSR are already used in the clinic, data on the influence of basic stimulus and recording parameters on chirp-evoked ASSR are not yet available. The multi-frequency chirp-evoked ASSR with optimised parameters may be the final step towards an objective assessment of frequency-specific thresholds in quiet in a clinic. The impact of stimulus and recording parameters is investigated in adult normal-hearing listeners and participants with a sensorineural hearing loss. These data are used as a basis for the optimisation of the parameters for a robust and efficient clinical ASSR recording.