正常成人听觉诱发电位P50的实验研究——定量测定大脑抑制功能的新指标

Study on auditory evoked potential P50 in normal adults: A quantitative test for brain inhibitory function

目的:探讨正常成人听觉诱发电位P50变化特点及其最佳表达方式。方法:应用听觉条件(S1)-测试刺激(S2)范式对30名正常受试者进行P50测试,分析P50在性别间的差异及其不同表达方式间的异同。结果:正常人S1诱发的P50波(S1鄄P50)潜伏期在Cz、Fz和Pz脑区分别为(61.07±14.05)ms、(63.47±15.02)ms和(56.42±20.49)ms,波幅分别为(3.83±3.33)μV、(3.67±2.53)μV和(3.07±2.81)μV;S2所诱发的P50波(S2鄄P50)潜伏期在Cz、Fz和Pz脑区分别为(52.27±32.34)ms、(54.53±30.43)ms和(47.25±33.32)ms,波幅分别为(1.40±1.44)μV、(1.36±1.24)μV和(1.12±1.28)μV;S2鄄P50波幅显著低于S1鄄P50(P<0.01),S2/S1比率为(38.34±29.64)%,其95%可信区间为32.06%～44.62%;S1鄄S2[波幅(μV)]和100(1-S2/S1)[波幅(μV)]的范围分别为(2.25±2.35)μV和(59.25±30.55)μV,其可信区间为1.75～2.75μV和52.78～65.72μV。男性与女性组S1鄄P50和S2鄄P50潜伏期和波幅没有差异。结论:听觉中潜伏期诱发电位P50是一种反映大脑抑制功能的脑电生理学新指标;通过其变化可反映大脑正常感觉门控的功能状态。其最佳表达方式是S1-S2[波幅(μV)]和100(1-S2/S1)[波幅(μV)]两种形式结合起来,能直接地表达感觉门控的程度。

Objective To observe the characteristics of auditory evoked potential P50 in normal adults and to analyse the optimal formula for stating brain inhibitory function. Methods: Auditory evoked potentials P50 were recor-ded in 30 normal adults by the conditioning/testing paradigm presented with auditory double clicks stimuli. Results The peak latencies of S1-P50 in Zones of Cz, Fz, and Pz of brain were (61.07±14.05)ms, (63.47±15.02)ms and (56.42±20.49)ms respectively. And amplitudes of S1-P50 in Zones of Cz, Fz, and Pz of brain were (3.83±3.33)μV, (3.67±2.53)μV and (3.07±2.81)μV. S2-P50 latencies in Zones of Cz, Fz and Pz of brain were (52.27±32.34)ms, (54.53±30.43)ms, (47.25±33.32)ms and amplitudes in Zones of Cz, Fz, and Pz sites were (1.40±1.44)μV, (1.36±1.24)μV and (1.12±1.28)μV respectively. No significant difference between S1-P50 and S2-P50 latency was found, but S2-P50 amplitude reduced significantly as compared with S1-P50 amplitude(P<0.01). The S2/S1 ratio and its 95% confidence interval were 38.34%±29.64% and (32.06-44.62)% respectively. The normal ranges of S2-S1 and 100(1-S2/S1) were (2.25±2.35)μV and (59.25±30.55)μV respectively, and their 95% confidence intervals were (1.75-2.75)μV and (52.78-65.72)μV respectively. There were no significant differences of the P50 amplitude and latency and S2/S1 ratio between male and female groups. Conclusions Auditory evoked potential P50 might be a new paramiter of brain suppressive potential. The changes of the S2/S1 ratio, S2-S1, and 100 (1-S2/S1) could reflect the state of function of brain sensory gating. And analyzing the results between S2-S1 and 100(1-S2/S1) is the optimal methed to realizing the brain inhibitory function.