BACKGROUND Neurovascular coupling (NVC) can be assessed using transcranial Doppler (TCD) measured task-activation of cerebral blood flow velocity (CBFv). However, not all individuals show consistent responses. The aim of this study was to develop a robust, objective, method to identify non-responders to task-activation. NEW METHOD Using five-minute seated resting (non-stimulated), bilateral CBFv data from 135 healthy participants, the cross-correlation function peak (CCF) between the population coherent average and each individual was obtained for a randomly selected segment of data (40 s) for both hemispheres (n = 270). The variance ratio (VR) was calculated by comparing the variance in CBFv data pre- and post-random mark. The 90th percentile for non-stimulated data was used to determine the upper confidence limit of normal variation in the CCF peak value (0.53), and VR (2.59). These criteria were then applied to task-activated CBFv from 69 healthy participants for five cognitive tasks (attention, verbal fluency, language, visuospatial, memory). RESULTS Data were accepted as responders if either CCF ≥ 0.53 or VR ≥ 2.59. The number of cases accepted as responders for each task were as follows: attention, 54-59 (78-86 %); verbal fluency, 42-48 (60-70 %); language, 51-53 (74-77 %); visuospatial, 54 (78 %); memory, 40-47 (58-68 %). COMPARISON WITH EXISTING METHOD Currently, there are no objective criteria for the identification of non-responders in studies of NVC. This is a new method to objectively classify non-responders to task-activation. CONCLUSIONS Using a large sample of resting CBFv data, we have set objective criteria to differentiate between responders and non-responders in task activation protocols.

中文翻译：

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在神经血管耦合测试中识别无反应者的客观方法。

背景技术可以使用经颅多普勒（TCD）测量的脑血流速度（CBFv）任务激活来评估神经血管耦合（NVC）。但是，并非所有人都表现出一致的反应。这项研究的目的是开发一种可靠，客观的方法来识别对任务激活无反应的人员。新方法使用来自135名健康参与者的五分钟就坐休息（非刺激）双侧CBFv数据，从随机选择的数据段中获得了总体一致平均值与每个个体之间的互相关函数峰（CCF）（40 s）两个半球（n = 270）。通过比较随机前和随机后CBFv数据中的方差来计算方差比（VR）。非刺激数据的第90个百分位数用于确定CCF峰值（0.53）和VR（2.59）的正常变化的置信上限。然后将这些标准应用于来自69位健康参与者的任务激活的CBFv，以执行五项认知任务（注意，口语流利度，语言，视觉空间，记忆）。结果如果CCF≥0.53或VR≥2.59，则将数据作为响应者。接受作为每个任务的响应者的病例数如下：注意，54-59（78-86％）；语言流利度为42-48（60-70％）；语言，51-53（74-77％）; 视觉空间，54（78％）; 记忆力40-47（58-68％）。与现有方法的比较目前，在NVC研究中没有客观标准可用于识别无反应者。这是一种客观地对任务激活的非响应者进行分类的新方法。