Yanshan University, School of Information Science and Engineering, Qinhuangdao, China.
McLean Hospital, McLean Imaging Center, Belmont, Massachusetts, United States.
J Biomed Opt. 2020 Jun;25(6):1-16. doi: 10.1117/1.JBO.25.6.065001.
Low-frequency oscillations (LFOs) ranging from 0.01 to 0.15 Hz are common in functional imaging studies. Some of these LFOs are non-neuronal and are correlated with autonomic physiological processes.
We investigate the relationships between systemic low-frequency oscillations (sLFOs) measured at different peripheral sites during resting states in ischemic stroke patients.
Twenty-seven ischemic stroke patients (ages 44 to 90; 20 male and 7 female) were recruited for the study. During the experiments, fluctuations in oxyhemoglobin concentration were measured in the left and right toes, fingertips, and earlobes using a multichannel near-infrared spectroscopy instrument. We applied cross-correlation and frequency component analyses on the sLFO data.
The results showed that embolization broke the symmetry of the sLFO transmission and that the damage was not limited to the local area but spread throughout the body. Among six peripheral sites, the power spectrum width of the earlobes was significantly larger than that of the fingers and toes. This indicates that the earlobes may contain more physiological information. Finally, the results of fuzzy clustering verified that sLFOs can serve as perfusion biomarkers to differentiate stroke from healthy subjects.
The high correlation values and corresponding delays in sLFOs support the hypothesis that (1) the correlation characteristics of sLFOs in stroke patients are different from those of healthy subjects. These characteristics can reflect patient condition, to an extent. Embolization in ischemic stroke patients breaks the symmetry of the body's sLFO transmission, disrupting the balance of blood circulation. (2) sLFOs can be used as perfusion biomarkers to differentiate ischemic stroke patients from healthy subjects. Studying these signals can explicate the overall feedback/influence of pericentral interactions. Finally, peripheral sLFOs have been shown to be an effective and accurate tool for assessing peripheral blood circulation and vascular integrity in ischemic stroke patients.
在功能成像研究中，频率在 0.01 到 0.15 Hz 之间的低频振荡（LFO）很常见。其中一些 LFO 是非神经元的，与自主生理过程相关。
我们研究了在缺血性脑卒中患者休息状态下，在不同外周部位测量的系统低频振荡（sLFO）之间的关系。
研究共招募了 27 名缺血性脑卒中患者（年龄 44 至 90 岁；20 名男性，7 名女性）。在实验过程中，使用多通道近红外光谱仪测量左、右脚趾、指尖和耳垂的氧合血红蛋白浓度波动。我们对 sLFO 数据进行了互相关和频率分量分析。
结果表明，栓塞破坏了 sLFO 传递的对称性，而且这种损伤不仅局限于局部区域，而是扩散到全身。在六个外周部位中，耳垂的功率谱宽度明显大于手指和脚趾。这表明耳垂可能包含更多的生理信息。最后，模糊聚类的结果验证了 sLFO 可以作为灌注生物标志物，将中风与健康受试者区分开来。
sLFO 的高相关值和相应的延迟支持了以下假设：（1）中风患者的 sLFO 相关特征与健康受试者不同。这些特征在一定程度上可以反映患者的病情。缺血性脑卒中患者的栓塞破坏了 sLFO 传递的对称性，打破了血液循环的平衡。（2）sLFO 可作为灌注生物标志物，将缺血性脑卒中患者与健康受试者区分开来。研究这些信号可以阐明中心周围相互作用的整体反馈/影响。最后，外周 sLFO 已被证明是评估缺血性脑卒中患者外周血液循环和血管完整性的有效和准确工具。
