The dimensionality of the Edinburgh Handedness Inventory: An analysis with models of the item response theory

Handedness is frequently measured with sum scores or quotients taken from laterality questionnaires like the Edinburgh Handedness Inventory (EHI). In classical test theory such data cannot be used to confirm either the unidimensionality (i.e., quantitative differentiation with the poles left-handed and right-handed) or multidimensionality (i.e., typological differentiation between left-, right-, and mixed-handers) of this personal characteristic. This study uses item response theory models to test the construct validity of the EHI on an item level in order to gather empirical support for the differentiation of handedness as well as the appropriateness of the items and the response format. The EHI was given to 540 participants (303 male and 237 female) aged 17–37 years. Results of mixed-Rasch analyses revealed that the best model was a two-class solution; that is, left- and right-handers (types) with quantitative differences between persons. Hence, unlike earlier model tests, this rejects both the unidimensionality of the handedness construct and the need to consider so-called mixed-handers. It is proposed that mixed-Rasch analyses should be applied more frequently to test the construct validity of other as well as more extensive handedness questionnaires.     

基于局域一致性分析的BOLD-fMRI探讨无灶性癫痫的发作机制

目的利用基于局域一致性（regional homogeneity,ReHo）分析方法的血氧水平依赖功能磁共振成像技术,探讨无灶性癫痫的发作机制。方法运用功能性磁共振成像技术,采集无灶性癫痫患者17例和健康对照组16例的静息态数据,然后运用局域一致性分析方法对数据进行分析,观察无灶性癫痫患者脑局域一致性与正常对照组的变化。结果无灶性癫痫组和健康对照组相比ReHo值增强的脑区主要分布在双侧海马;ReHo值降低的脑区主要分布在右顶叶、右中央前回、右额叶、右侧小脑半球及左楔前叶、左前额。结论无灶性癫痫患者静息状态下脑功能活动较对照组有所改变,ReHo值升高的脑区反映了该脑区参与了癫痫的高活动,而降低的脑区可能反应了由于长期癫痫发作导致这些区域的神经元受损。     

基于局部一致性的重度抑郁症患者脑静息态功能磁共振成像研究

目的 采用脑静息态功能磁共振成像(rs-fMRI)局部一致性(ReHo)方法探讨重度抑郁症(MDD)患者脑区自发性活动特征,评价其与抑郁严重程度的相关性.方法 对24例MDD患者和26例相匹配的康对照组(HC)进行rs-fMRI扫描,分析两组ReHo值,将差异显著的脑区内平均ReHo值与HAMD-17评分进行相关性分析.结果 MDD患者较HC组左侧直回、左侧海马、右侧楔前叶、右侧顶上回、左侧顶下缘角回、右侧楔叶ReHo值显著升高;右背外侧前额叶、右侧后扣带回、左侧枕下回、双侧颞下回、右侧颞上回ReHo值降低(P<0.05,Alphasim矫正).Pearson相关分析显示两组差异脑区左侧海马ReHo值与HAMD-17评分呈正相关(r=0.593,P=0.002),右侧后扣带回ReHo值与HAMD-17评分呈负相关(r=-0.431,P=0.035).结论 MDD患者静息态下脑功能损害主要集中于边缘系统及默认网络等多个脑区,且左侧海马与右侧后扣带回局部脑区自发活动的时间同步性与抑郁严重程度存在相关性.ReHo分析可作为抑郁症严重程度评价的潜在生物学标记.     

基于中国人脑图谱Chinese2020配准的阿尔茨海默病患者静息态fMRI

目的 探讨基于中国人脑图谱Chinese2020配准的静息态功能MR数据分析在阿尔茨海默病（AD）患者中的应用价值。方法 收集12例AD患者（AD组）和17名健康志愿者（正常对照组）,基于中国人脑图谱Chinese2020和传统标准脑图谱ICBM152配准对静息态数据进行全脑分析,运用低频振幅（ALFF）和局部一致性（ReHo）分析方法,评估AD患者脑局部神经元自发活动的变化,并比较基于2种脑图谱配准计算的AD患者ALFF和ReHo差异性脑区的分布。结果 基于2种脑图谱的数据分析均发现,与正常对照组比较,AD组右侧颞上回、右侧楔前叶和右侧角回ALFF值减低,左侧小脑、左侧颞极、颞上回和颞中回ALFF升高（P均<0.05）;AD组左侧颞中回、右侧颞下回、左侧三角部额下回和左侧楔叶ReHo值减低,左侧小脑ReHo值升高（P均<0.05）。基于Chinese2020分析获得的相同的差异脑区平均灰质占比[ALFF：（38.85±17.88）%;ReHo：（54.69±13.28）%]高于基于传统脑图谱ICBM152分析[ALFF：（33.75±14.70）%;ReHo：（45.66±12.35）%],但差异无统计学意义（P=0.68、0.21）。结论 基于中国人脑图谱Chinese2020配准的静息态功能磁共振数据分析在检测中国AD患者的局部神经元自发活动方面较传统的西方人脑图谱更准确。     

Expertise modulates local regional homogeneity of spontaneous brain activity in the resting brain: An fMRI study using the model of skilled acupuncturists

Studies on training/expertise‐related effects on human brain in context of neuroplasticity have revealed that plastic changes modulate not only task activations but also patterns and strength of internetworks and intranetworks functional connectivity in the resting state. Much has known about plastic changes in resting state on global level; however, how training/expertise‐related effect affects patterns of local spontaneous activity in resting brain remains elusive. We investigated the homogeneity of local blood oxygen level‐dependent fluctuations in the resting state using a regional homogeneity (ReHo) analysis among 16 acupuncturists and 16 matched nonacupuncturists (NA). To prove acupuncturists' expertise, we used a series of psychophysical tests. Our results demonstrated that, acupuncturists significantly outperformed NA in tactile‐motor and emotional regulation domain and the acupuncturist group showed increased coherence in local BOLD signal fluctuations in the left primary motor cortex (MI), the left primary somatosensory cortex (SI) and the left ventral medial prefrontal cortex/orbitofrontal cortex (VMPFC/OFC). Regression analysis displayed that, in the acupuncturists group, ReHo of VMPFC/OFC could predict behavioral outcomes, evidenced by negative correlation between unpleasantness ratings and ReHo of VMPFC/OFC and ReHo of SI and MI positively correlated with the duration of acupuncture practice. We suggest that expertise could modulate patterns of local resting state activity by increasing regional clustering strength, which is likely to contribute to advanced local information processing efficiency. Our study completes the understanding of neuroplasticity changes by adding the evidence of local resting state activity alterations, which is helpful for elucidating in what manner training effect extends beyond resting state. Hum Brain Mapp 35:1074–1084, 2014. © 2013 Wiley Periodicals, Inc.     

Placebo analgesia and reward processing: Integrating genetics,personality, and intrinsic brain activity

Our expectations about an event can strongly shape our subjective evaluation and actual experience of events. This ability, applied to the modulation of pain, has the potential to affect therapeutic analgesia substantially and constitutes a foundation for non‐pharmacological pain relief. A typical example of such modulation is the placebo effect. Studies indicate that placebo may be regarded as a reward, and brain activity in the reward system is involved in this modulation process. In the present study, we combined resting‐state functional magnetic resonance imaging (rs‐fMRI) measures, genotype at a functional COMT polymorphism (Val158Met), and personality measures in a model to predict the magnitude of placebo conditioning effect indicated by subjective pain rating reduction to calibrated noxious stimuli. We found that the regional homogeneity (ReHo), an index of local neural coherence, in the ventral striatum, was significantly associated with conditioning effects on pain rating changes. We also found that the number of Met alleles at the COMT polymorphism was linearly correlated to the suppression of pain. In a fitted regression model, we found the ReHo in the ventral striatum, COMT genotype, and Openness scores accounted for 59% of the variance in the change in pain ratings. The model was further tested using a separate data set from the same study. Our findings demonstrate the potential of combining resting‐state connectivity, genetic information, and personality to predict placebo effect. Hum Brain Mapp 35:4583–4593, 2014. © 2014 Wiley Periodicals, Inc.     

Testing homogeneity of proportion ratios for stratified correlated bilateral data in two‐arm randomized clinical trials

Stratified data analysis is an important research topic in many biomedical studies and clinical trials. In this article, we develop five test statistics for testing the homogeneity of proportion ratios for stratified correlated bilateral binary data based on an equal correlation model assumption. Bootstrap procedures based on these test statistics are also considered. To evaluate the performance of these statistics and procedures, we conduct Monte Carlo simulations to study their empirical sizes and powers under various scenarios. Our results suggest that the procedure based on score statistic performs well generally and is highly recommended. When the sample size is large, procedures based on the commonly used weighted least square estimate and logarithmic transformation with Mantel–Haenszel estimate are recommended as they do not involve any computation of maximum likelihood estimates requiring iterative algorithms. We also derive approximate sample size formulas based on the recommended test procedures. Finally, we apply the proposed methods to analyze a multi‐center randomized clinical trial for scleroderma patients. Copyright © 2014 John Wiley & Sons, Ltd.