Bernstein L R, Trahiotis C
Department of Surgery (Otolaryngology), University of Connecticut Health Center, Farmington 06030, USA.
J Acoust Soc Am. 1999 Mar;105(3):1776-83. doi: 10.1121/1.426715.
A two-interval, two-alternative temporal forced-choice procedure was used to measure NoSo and NoS pi masked thresholds with 500-Hz and 4-kHz tonal signals. The duration of the signal was either 10, 20, 40, or 320 ms. The maskers were 200-Hz-wide bands of Gaussian noise centered at the frequency of the signal and presented continuously. Decreasing the duration of the 500-Hz tonal signal resulted in a modest increase (1.5 dB or so) in the masking-level difference (MLD) measured between NoSo and NoS pi conditions. In contrast, decreasing the duration of the 4-kHz tonal signal resulted in a substantial decrease (4.5 dB or so) in the MLD. Comparisons of the data with thresholds predicted from analyses based on "windows of temporal integration" provided quantitatively acceptable accounts of the data. The data obtained in the NoS pi condition at 4 kHz, which are novel and were of primary interest, were well-accounted for in a statistical sense. However, there were small, but systematic, discrepancies between the predictions and the data. Those discrepancies, although small in magnitude, suggest that binaural temporal integration at high frequencies, where the envelopes of the stimuli convey the information, may be inherently different from both monaural temporal integration and binaural temporal integration at low frequencies.
采用双间隔、双备选的时间强制选择程序，用500赫兹和4千赫兹的音调信号测量了非同时掩蔽（NoSo）和非同时π掩蔽（NoSπ）阈值。信号持续时间为10、20、40或320毫秒。掩蔽声为以信号频率为中心、带宽200赫兹的高斯噪声带，并持续呈现。500赫兹音调信号持续时间的缩短，导致在非同时掩蔽（NoSo）和非同时π掩蔽（NoSπ）条件下测量的掩蔽级差（MLD）适度增加（约1.5分贝）。相比之下，4千赫兹音调信号持续时间的缩短，导致掩蔽级差（MLD）大幅下降（约4.5分贝）。将这些数据与基于“时间整合窗口”分析预测的阈值进行比较，在定量上能够较好地解释这些数据。在4千赫兹非同时π掩蔽（NoSπ）条件下获得的、新颖且最受关注的数据，从统计学意义上得到了很好的解释。然而，预测结果与数据之间存在微小但系统的差异。这些差异虽然幅度较小，但表明在高频处，刺激的包络传递信息，其双耳时间整合可能与低频处的单耳时间整合和双耳时间整合本质上有所不同。
