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可移动脑磁图阵列可有效采集平原健康人群初级听觉诱发的响应信号

Movable Array of Magnetoencephalography With Optically Pumped Magnetometers Effectively Captures Primary Auditory-Evoked Response Signals in Healthy Populations at Low Altitudes

  • 摘要:
    目的 探讨可移动(指探测器到颞叶头皮的距离可以移动)阵列光泵磁力仪脑磁图(optically pumped magnetometers-magnetoencephalography, OPM-MEG)是否可以有效采集平原健康受试者听觉诱发的响应信号,为后续在长期高原居住人群中探讨脑功能变化提供有益的技术参考。
    方法 本研究共招募了40名平原(海拔470 m)健康受试者,通过调整两侧颞叶探测器与头皮的距离,比较不同距离下(0 mm、5 mm、10 mm、15 mm)的颞叶听觉响应信号,分析每个被试在不同距离下的M100峰值信号强度、噪声、信噪比和潜伏期,以及对应的听觉溯源定位图。通过单因素检验,比较在不同距离下,探测器响应信号的差异。
    结果 随着探测器与头皮距离的增加,噪声、信号、信噪比逐渐衰弱(P<0.001);噪声和信号呈线性衰减趋势,但信噪比在5 mm时值最大,并未呈现出线性衰减的趋势;潜伏期不受距离影响(P=0.72);溯源定位结果基本一致。
    结论 探测器和头皮的距离在5 mm时,信噪比值最高,能够达到高灵敏度和高信号强度。即使探测距离达到15 mm,OPM-MEG信噪比依然高于16 dB,能够满足临床的信号采集需求;进一步,溯源定位结果也基本一致,距离变化并不会影响溯源结果的可用性,证实了该设备的信号采集有效性。

     

    Abstract:
    Objective To investigate the effectiveness of a movable (with the distance between the temporal scalp and the detector being adjustable) array of optically pumped magnetometers for magnetoencephalography (OPM-MEG) in capturing auditory evoked response signals in healthy subjects living at low altitudes, and to provide a useful technical reference for subsequent exploration of the changes in brain functions in populations living at high altitudes on a long-term basis.
    Methods Forty healthy subjects living at a low altitude (470 m above sea level) were recruited. The distance between the scalp and the bilateral temporal lobe detector was adjusted, and the subjects' auditory responses in the temporal lobes were recorded at the distances of 0 mm, 5 mm, 10 mm, and 15 mm. For the different distances, the M100 peak signal strength, noise, signal-to-noise ratio (SNR), and latency were analyzed along with the corresponding auditory source localization maps. A single-factor analysis of variance was conducted to compare the differences in response signals at varying distances.
    Results As the distance between the scalp and the detector increased, the noise, the signal, and the SNR gradually weakened (P<0.001). The noise and signal showed a tendency of linear decline. On the other hand, the SNR reached its maximum at 5 mm and did not show a tendency of linear decline. Latency was not affected by the distance (P=0.72). The results of the auditory stimulus source reconstruction were generally consistent.
    Conclusions When the distance between the detector and the scalp is 5 mm, the SNR value is the highest, resulting in high sensitivity and high signal strength. On the other hand, even when the distance between the detector and the scalp reaches 15 mm, the SNR of the OPM-MEG is still higher than 16 dB, which meets the clinical signal acquisition requirements. Furthermore, the auditory stimulus source reconstruction results were generally consistent. Changing the scalp-to-detector distance does not affect the applicability of the source localization results, validating the device's effectiveness in signal acquisition.

     

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