Oates P, Stapells D R
Auditory Evoked Potentials Research Laboratory, Albert Einstein College of Medicine, Bronx, New York, USA.
J Acoust Soc Am. 1997 Dec;102(6):3597-608. doi: 10.1121/1.420148.
This study investigated the frequency specificity of the auditory brainstem (ABR) and middle latency (MLR) responses to 500- and 2000-Hz brief tones using high-pass noise masking. Stimuli were linear- (2-1-2 cycles) and exact-Blackman- (5 cycles) gated tones presented at 80 dB peak-to-peak equivalent (ppe) SPL. Cochlear contributions to ABR wave V-V' and MLR wave Na-Pa were assessed by the effects of high-pass noise masking on response amplitudes and latencies. The high-pass noise results demonstrate that the ABR and the MLR to the 80 dB ppe SPL brief tones show good frequency and place specificity. Changes in ABR or MLR amplitude and latency with high-pass noise masking did not occur as the masker cutoff was decreased from 2 to 3 octaves above the stimulus nominal frequency until it was within one-half octave of this frequency, below which amplitudes rapidly decreased (500- and 2000-Hz tones) and latencies increased (500-Hz tones). No significant differences existed in the frequency specificity of the ABR versus MLR, or in these evoked potentials to exact-Blackman- versus linear-gated tones.
本研究使用高通噪声掩蔽，调查了听性脑干反应（ABR）和中潜伏期反应（MLR）对500赫兹和2000赫兹短纯音的频率特异性。刺激声为峰峰值等效声压级（ppe）80分贝时呈现的线性门控（2-1-2周期）和精确布莱克曼门控（5周期）短纯音。通过高通噪声掩蔽对反应幅度和潜伏期的影响，评估耳蜗对ABR波V-V'和MLR波Na-Pa的贡献。高通噪声结果表明，对峰峰值等效声压级80分贝短纯音的ABR和MLR表现出良好的频率和部位特异性。随着掩蔽截止频率从高于刺激标称频率2到3倍频程降低至该频率的半个倍频程以内，高通噪声掩蔽时ABR或MLR的幅度和潜伏期没有变化，低于此频率时，幅度迅速下降（500赫兹和2000赫兹短纯音），潜伏期增加（500赫兹短纯音）。ABR与MLR的频率特异性，或这些诱发电位对精确布莱克曼门控与线性门控短纯音的频率特异性，均无显著差异。
