Johnson Tiffany A, Brown Carolyn J
Department of Speech Pathology and Audiology, University of Iowa, Iowa City, Iowa, USA.
Ear Hear. 2005 Dec;26(6):559-76. doi: 10.1097/01.aud.0000188105.75872.a3.
The purpose of this study was to evaluate the accuracy with which auditory steady-state response (ASSR) and tone burst auditory brain stem response (ABR) thresholds predict behavioral thresholds, using a within-subjects design. Because the spectra of the stimuli used to evoke the ABR and the ASSR differ, it was hypothesized that the predictive accuracy also would differ, particularly in subjects with steeply sloping hearing losses.
ASSR and ABR thresholds were recorded in a group of 14 adults with normal hearing, 10 adults with flat, sensorineural hearing losses, and 10 adults with steeply sloping, high-frequency, sensorineural hearing losses. Evoked-potential thresholds were recorded at 1, 1.5, and 2 kHz and were compared with behavioral, pure-tone thresholds. The predictive accuracy of two ABR protocols was evaluated: Blackman-gated tone bursts and linear-gated tone bursts presented in a background of notched noise. Two ASSR stimulation protocols also were evaluated: 100% amplitude-modulated (AM) sinusoids and 100% AM plus 25% frequency-modulated (FM) sinusoids.
The results suggested there was no difference in the accuracy with which either ABR protocol predicted behavioral threshold, nor was there any difference in the predictive accuracy of the two ASSR protocols. On average, ABR thresholds were recorded 3 dB closer to behavioral threshold than ASSR thresholds. However, in the subjects with the most steeply sloping hearing losses, ABR thresholds were recorded as much as 25 dB below behavioral threshold, whereas ASSR thresholds were never recorded more than 5 dB below behavioral threshold, which may reflect more spread of excitation for the ABR than for the ASSR. In contrast, the ASSR overestimated behavioral threshold in two subjects with normal hearing, where the ABR provided a more accurate prediction of behavioral threshold.
Both the ABR and the ASSR provided reasonably accurate predictions of behavioral threshold across the three subject groups. There was no evidence that the predictive accuracy of the ABR evoked using Blackman-gated tone bursts differed from the predictive accuracy observed when linear-gated tone bursts were presented in conjunction with notched noise. Similarly, there was no evidence that the predictive accuracy of the AM ASSR differed from the AM/FM ASSR. In general, ABR thresholds were recorded at levels closer to behavioral threshold than the ASSR. For certain individuals with steeply sloping hearing losses, the ASSR may be a more accurate predictor of behavioral thresholds; however, the ABR may be a more appropriate choice when predicting behavioral thresholds in a population where the incidence of normal hearing is expected to be high.
本研究旨在采用受试者内设计，评估听觉稳态反应（ASSR）和短纯音听觉脑干反应（ABR）阈值预测行为阈值的准确性。由于用于诱发ABR和ASSR的刺激频谱不同，因此推测预测准确性也会有所不同，尤其是在听力损失呈陡坡状的受试者中。
对14名听力正常的成年人、10名患有平坦型感音神经性听力损失的成年人以及10名患有陡坡状高频感音神经性听力损失的成年人进行了ASSR和ABR阈值记录。在1、1.5和2千赫处记录诱发电位阈值，并与行为纯音阈值进行比较。评估了两种ABR方案的预测准确性：在带陷噪声背景下呈现的布莱克曼门控短纯音和线性门控短纯音。还评估了两种ASSR刺激方案：100%调幅（AM）正弦波和100% AM加25%调频（FM）正弦波。
结果表明，两种ABR方案预测行为阈值的准确性没有差异，两种ASSR方案的预测准确性也没有差异。平均而言，记录的ABR阈值比ASSR阈值更接近行为阈值3分贝。然而，在听力损失坡度最陡的受试者中，记录的ABR阈值比行为阈值低达25分贝，而ASSR阈值从未比行为阈值低超过5分贝，这可能反映出ABR的兴奋扩散比ASSR更多。相比之下，在两名听力正常的受试者中，ASSR高估了行为阈值，而ABR对行为阈值的预测更准确。
ABR和ASSR在三个受试者组中都对行为阈值提供了合理准确的预测。没有证据表明使用布莱克曼门控短纯音诱发的ABR的预测准确性与在带陷噪声中呈现线性门控短纯音时观察到的预测准确性不同。同样，没有证据表明AM ASSR的预测准确性与AM/FM ASSR不同。一般来说，记录的ABR阈值比ASSR更接近行为阈值。对于某些听力损失呈陡坡状的个体，ASSR可能是行为阈值的更准确预测指标；然而，在预计听力正常发生率较高的人群中预测行为阈值时，ABR可能是更合适的选择。
