PDF(Pubmed)
Abstract：
UNASSIGNED: Visual analogue scales are widely used to measure subjective responses. Norris\' 16 visual analogue scales (N_VAS) measure subjective feelings of alertness and mood. Up to now, different scientists have clustered items of N_VAS into different ways and Bond and Lader\'s way has been the most frequently used in clinical research. However, there are concerns about the stability of this clustering over different subject samples and different drug classes. The aim of this study was to test whether Bond and Lader\'s clustering was stable in terms of subject samples and drug effects. Alternative clustering of N_VAS was tested.Data from studies with 3 types of drugs: cannabinoid receptor agonist (delta-9-tetrahydrocannabinol [THC]), muscarinic antagonist (scopolamine), and benzodiazepines (midazolam and lorazepam), collected between 2005 and 2012, were used for this analysis. Exploratory factor analysis (EFA) was used to test the clustering algorithm of Bond and Lader. Consensus clustering was performed to test the stability of clustering results over samples and over different drug types. Stability analysis was performed using a three-cluster assumption, and then on other alternative assumptions.Heat maps of the consensus matrix (CM) and density plots showed instability of the three-cluster hypothesis and suggested instability over the 3 drug classes. Two- and four-cluster hypothesis were also tested. Heat maps of the CM and density plots suggested that the two-cluster assumption was superior.In summary, the two-cluster assumption leads to a provably stable outcome over samples and the 3 drug types based on the data used.
摘要：
■视觉模拟量表广泛用于测量主观反应。Norris\'16视觉模拟量表（N_VAS）测量警觉性和情绪的主观感觉。到目前为止,不同的科学家将N_VAS的项目聚集成不同的方式，而Bond和Lader的方式是临床研究中最常用的方式。然而,人们担心这种聚类在不同受试者样本和不同药物类别上的稳定性。这项研究的目的是测试Bond和Lader的聚类在受试者样本和药物作用方面是否稳定。测试了N_VAS的替代聚类。来自3种药物的研究数据：大麻素受体激动剂（δ-9-四氢大麻酚[THC]），毒蕈碱拮抗剂（东pol碱），和苯二氮卓类药物（咪达唑仑和劳拉西泮），2005年至2012年收集的数据用于本分析。采用探索性因子分析(EFA)对Bond和Lader的聚类算法进行检验。进行一致性聚类以测试样本和不同药物类型的聚类结果的稳定性。使用三簇假设进行稳定性分析，然后是其他替代假设。共识矩阵（CM）的热图和密度图显示了三簇假设的不稳定性，并暗示了3种药物类别的不稳定性。还测试了二簇和四簇假设。CM和密度图的热图表明，两个集群的假设是更好的。总之,根据所使用的数据,二组假设可证明样本和3种药物类型的结果稳定.
