Objective: This study investigates the effect of signal-to-noise ratio (SNR), frequency, and bandwidth on horizontal sound localization accuracy in normal-hearing young adults. Methods: From August 2022 to December 2022, a total of 20 normal-hearing young adults, including 7 males and 13 females, with an age range of 20 to 35 years and a mean age of 25.4 years, were selected to participate in horizontal azimuth recognition tests under both quiet and noisy conditions. Six narrowband filtered noise stimuli were used with central frequencies (CF) of 250, 2 000, and 4 000 Hz and bandwidths of 1/6 and 1 octave. Continuous broadband white noise was used as the background masker, and the signal-to-noise ratio (SNR) was 0, -3, and -12 dB. The root-mean-square error (RMS error) was used to measure sound localization accuracy, with smaller values indicating higher accuracy. Friedman test was used to compare the effects of SNR and CF on sound localization accuracy, and Wilcoxon signed-rank test was used to compare the impact of the two bandwidths on sound localization accuracy in noise. Results: In a quiet environment, the RMS error in horizontal azimuth in normal-hearing young adults ranged from 4.3 to 8.1 degrees. Sound localization accuracy decreased with decreasing SNR: at 0 dB SNR (range: 5.3-12.9 degrees), the difference from the quiet condition was not significant (P>0.05); however, at -3 dB (range: 7.3-16.8 degrees) and -12 dB SNR (range: 9.4-41.2 degrees), sound localization accuracy significantly decreased compared to the quiet condition (all P<0.01). Under noisy conditions, there were differences in sound localization accuracy among stimuli with different frequencies and bandwidths, with higher frequencies performing the worst, followed by middle frequencies, and lower frequencies performing the best, with significant differences (all P<0.01). Sound localization accuracy for 1/6 octave stimuli was more susceptible to noise interference than 1 octave stimuli (all P<0.01). Conclusions: The ability of normal-hearing young adults to localize sound in the horizontal plane in the presence of noise is influenced by SNR, CF, and bandwidth. Noise with SNRs of ≥-3 dB can lead to decreased accuracy in narrowband sound localization. Higher CF signals and narrower bandwidths are more susceptible to noise interference.
目的： 探究信噪比和刺激声频率、带宽对正常听力青年人噪声下水平方位声源定位精度的影响。 方法： 本研究为自身对照横断面设计研究，2022年8—12月选取正常听力青年人20名，其中男性7名，女性13名，年龄范围20~35岁，平均年龄25.4岁。进行安静和噪声下水平方位声源定位角度识别测试，使用6种窄带白噪声作为刺激声，中心频率（central frequency，CF）为250、2 000和4 000 Hz，带宽为1/6和1倍频程，使用信噪比为0、-3和-12 dB的宽带白噪声作为掩蔽声，计算均方根误差（root-mean-square error，RMS error）作为声源定位精度，数值越小表示定位精度越高。采用Friedman秩和检验比较CF和信噪比对声源定位精度的影响，Wilcoxon符号秩和检验比较两种带宽对声源定位精度的影响。 结果： 正常听力青年人安静环境下的水平方位角度识别误差RMS error为4.3~8.1°，噪声下定位精度随着信噪比下降而降低：0 dB信噪比（5.3~12.9°）与安静环境下差异无统计学意义（P>0.05）；在-3 dB（7.3~16.8°）和-12 dB（9.4~41.2°）信噪比时，声源定位精度显著下降，与安静下相比，差异具有统计学意义（P值均<0.01）。在噪声下，不同频率和带宽刺激声的声源定位精度存在差异，高频最差、中频次之、低频最好，差异具有统计学意义（P值均<0.01）。1/6倍频程刺激声的声源定位精度比1倍频程更容易受到噪声干扰，差异具有统计学意义（P值均<0.01）。 结论： 正常听力青年人噪声下水平方位声源定位能力受到信噪比和刺激声频率、带宽的影响，-3 dB以上信噪比的噪声可导致窄带声源水平位置识别精度下降，信号的CF愈高、带宽愈窄，越容易受到噪声干扰。.