van Straaten E C W, den Haan J, de Waal H, van der Flier W M, Barkhof F, Prins N D, Stam C J
Department of Clinical Neurophysiology, VU University Medical Center, Amsterdam, The Netherlands; Nutricia Advanced Medical Nutrition, Danone Research, Centre for Specialised Nutrition, Wageningen, The Netherlands.
Department of Clinical Neurophysiology, VU University Medical Center, Amsterdam, The Netherlands.
Clin Neurophysiol. 2015 Mar;126(3):497-504. doi: 10.1016/j.clinph.2014.05.018. Epub 2014 Jun 4.
White matter hyperintensities (WMH), a feature seen on magnetic resonance imaging (MRI) and regarded to reflect small vessel disease, can lead to vascular dementia (WMH-VaD). In WMH-VaD, cognitive deficits typically consist of executive function disturbances, and reduced information processing speed, regarded as a result of cerebral hypoperfusion. We aimed to investigate whether this patient group has typical functional differences from controls.
Resting-state encephalography studies of 17 VaD patients and 17 age- and gender matched non-demented controls were analysed in the delta, theta, alpha1 and 2, and beta frequency bands. Undirected functional connectivity between electrodes was established with the Phase Lag Index (PLI) and directed functional connectivity with the directed Phase Lag Index (dPLI). PLI and dPLI were related to performance in cognitive testing.
Mean PLI did not differ between patients and controls. In the control group dPLI showed anterior to posterior phase gradients in all bands except the delta band. In the VaD patient group this pattern was significantly different without a clear directional pattern. No relationship with cognition was demonstrated.
This study shows a clear front-to-back direction of connectivity in non-demented controls. In VaD patients with extensive WMH, this pattern is disturbed.
Structural damage at the regions of long distance white matter tracts may induce changes in the direction of phase relationships of distinct brain regions.
白质高信号（WMH）是磁共振成像（MRI）上可见的一种特征，被认为反映小血管疾病，可导致血管性痴呆（WMH-VaD）。在WMH-VaD中，认知缺陷通常包括执行功能障碍和信息处理速度降低，这被认为是脑灌注不足的结果。我们旨在研究该患者组与对照组是否存在典型的功能差异。
对17例VaD患者和17例年龄及性别匹配的非痴呆对照进行静息态脑电研究，分析其在δ、θ、α1和α2以及β频段的情况。通过相位滞后指数（PLI）建立电极间的无向功能连接，并通过定向相位滞后指数（dPLI）建立定向功能连接。PLI和dPLI与认知测试表现相关。
患者和对照组的平均PLI无差异。在对照组中，除δ频段外，dPLI在所有频段均显示从前向后的相位梯度。在VaD患者组中，这种模式明显不同，没有明确的方向模式。未显示与认知有相关性。
本研究显示非痴呆对照组中存在明确的前后连接方向。在患有广泛WMH的VaD患者中，这种模式受到干扰。
长距离白质束区域的结构损伤可能会引起不同脑区相位关系方向的变化。
