不同强度非靶刺激声对听觉事件相关电位 P300的影响

目的：比较不同强度非靶刺激声诱发的听觉事件相关电位（auditory event －related potential ， AERP）P300波潜伏期和幅值，探讨相同频率刺激声条件下诱导典型P300波形所需的靶刺激和非靶刺激声强度。方法对20例健康青年志愿者，均采用相同的短纯音靶刺激声（1 kHz ，60 dB nHL）和三种不同强度（50、65、70dBnHL，1kHz）的非靶刺激声（短纯音）进行3次AERP测试，比较其P300的潜伏期和幅值。结果每例受试者均能诱发出P300，70、65、50dBnH L非靶刺激声强度下，P300潜伏期分别为316．25±21．16、320．83±22．64、318．44±25．82ms，差异无统计学意义（P＞0．05）；幅值分别为5．02±2．04、7．42±2．58、3．54±2．23μV，65dBnHL所诱发的P300幅值显著大于70和50 dB n H L所诱发的幅值，差异有统计学意义（ P＜0．01），70和50 dB n H L所诱发的P300幅值差异无统计学意义（ P＞0．05）。结论改变非靶刺激声强度对P300波潜伏期无明显影响，但能显著改变幅值；相同频率刺激声条件下，靶刺激和非靶刺激声强度分别为60 dBnHL和65dBnHL时能诱发出典型的P300波形。

The Effects of Different in Nontarget Stimulus Intensity on Auditory Event-related Potential P300

Objective To compare the latency and amplitude of normal subject's auditory event -related po‐tentials(AERP) via P300 evoked by same target stimulation and different intensitve non target stimulation ,and to explore the appropriate intensity of target and nontarget stimulus which evoke typical P300 at the same frequency . Methods A total of 20 normal young volunteers were induced in this study .Each subject received 3 AERP tests , respectively by the same tone burst target stimulus(60 dB nHL ,1 kHz) and different intensity levels for the non target stimulus(50 ,65 ,70 dB nHL ,and 1 kHz) ,and the latency and amplitude of 3 group's P300 were compared . Results In all cases ,P300 was successfully induced .The latencies of 3 group's P300 were 316 .25 ± 21 .16 ms , 320 .83 ± 22 .64 ms ,318 .44 ± 25 .82 ms (P>0 .05) ,respectively and the amplitudes of 3 group's P300 were 5 .02 ± 2 .04 μV ,7 .42 ± 2 .58 μV ,3 .54 ± 2 .23 μV (P<0 .01) ,respectively .The amplitude of the moderate intensity group was greater than the high intensity group and low intensity group ,and the amplitude differences were not statistical‐ly significant between the high and the low intensity groups .Conclusion Different intensity levels of nontarget stim‐ulus do not affect the latency of P300 ,but significantly affect the amplitude .Along with the decreasing of the inten‐sity difference of target and nontarget stimula ,the P300 amplitude raise gradually .A typical P300 is induced at the same frequency when the target stimuli and non target stimuli are 60 dB nHL and 65 dB nHL respectively .