耳聲傳射是耳蝸外毛細胞所產生的訊號，變頻耳聲傳射為耳聲傳射的其中一種。在
過去，我們使用傳統的兩個純音作為變頻耳聲傳射的刺激信號。然而，如果要量測多組
不同頻率的耳聲傳射，這個方法效率不佳，因此我們在此研究使用指數型掃頻正弦波作
為刺激信號，掃頻正弦波是一種頻率隨時間變化的正弦波，其頻率變化速度呈現指數增
長，因此我們能夠在短時間內得到高頻率解析度的變頻耳聲傳射，在本研究中，每次量
測僅需兩秒，重複量測不須花太多時間。在分析過程中，本研究未使用偽影去除法進行
降噪，而是採用同步壓縮變換以及正弦模型。同步壓縮變換是根據短時傅立葉變換進行
改進，其核心概念在每個時間點中，將能量集中到最接近瞬時頻率的位置，以此提高頻
率的解析度，同步壓縮變換可使時頻圖中的頻率軌跡更細、更精準，因此我們認為同步
壓縮變換可以幫助降噪。正弦模型幫助我們在時域中重建同步壓縮變換後的訊號，其架
構為分析與合成兩部份所組成。在此研究中，我們招募五名聽力正常的受試者，結果表
明經由同步壓縮變換與正弦模型處理後的變頻耳聲傳射，與原始信號相似，但波動振幅
較小，除此之外，當量測次數減少時，信號更容易受噪音影響，因此在患者時間寶貴的
情況下，如果能縮短量測次數，就能增加量測效率，並且彰顯同步壓縮變換與正弦模型
處理展現出臨床應用的潛力。

Distortion-product otoacoustic emission (DPOAE) is one kind of otoacoustic emission (OAE), generated in the outer hair cells (OHCs) of the cochlea. In the past, two pure tones were used as the stimuli for DPOAE measurement. However, this method is inefficient if one desires to measure DPOAE at multiple frequencies. Therefore, we used the exponential swept-sine waves as stimuli in this study instead. A swept-sine wave is a sine wave whose frequency varies (increases or decreases) exponentially. This allows us to obtain a broad bandwidth of DPOAEs within a short time. For each repetition in our measurement, it only took two seconds. Thus, the repeated measurements would not take much time. During the analysis process, we abandoned the noise artifact rejection. Instead, we employed the synchrosqueezing transform (SST) and sinusoidal modeling. The SST, based on the concept that concentrating the energy to the locations that more accurately reflect the true instantaneous frequency at each time index, is an improved version of the short-time Fourier transform (STFT). The SST spectrogram shows that the swept-sine trajectories are thinner and more precise compared to those in the STFT spectrogram, indicating the SST is helpful in detecting a signal in a noisy background. Based on the results of SST, the sinusoidal modeling, composed of analysis and synthesis, was used to reconstruct the signal in time domain. In this study, we recruited five subjects with normal hearing. The results shows that the DPOAE signals derived from the SST and sinusoidal modeling are similar to the original one but exhibit less fluctuation. This allows for a reduction in the number of repeated measurements, thereby increasing efficiency and showing potentials in clinical application scenarios where patients’ time is precious.

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