Reichenheim Michael, Souza Wanderson, Coutinho Evandro Silva Freire, Figueira Ivan, Quintana Maria Inês, de Mello Marcelo Feijó, Bressan Rodrigo Affonseca, de Jesus Mari Jair, Andreoli Sergio Baxter
Department of Epidemiology, Institute of Social Medicine (IMS), State University of Rio de Janeiro (UERJ), Rio de Janeiro, RJ, Brazil.
Department of Psychology, Institute of Education, Federal Rural University of Rio de Janeiro (UFRRJ), Seropédica, RJ, Brazil.
PLoS One. 2014 Apr 18;9(4):e94367. doi: 10.1371/journal.pone.0094367. eCollection 2014.
Tonic Immobility is a temporary state of motor inhibition in situations involving extreme fear. The first scale developed for its assessment was the 10-item Tonic Immobility Scale (TIS). However, there are still few studies on its structural (dimensional) validity. The objective of this study was to reassess the factor structure of the TIS applied to representative samples exposed to general trauma of two Brazilian mega-cities.
The sample comprised 3,223 participants reporting at least one traumatic experience. In São Paulo (n = 2,148), a Confirmatory Factor Analysis (CFA) first tested the originally proposed two-dimensional structure. This was followed by sequential Exploratory Structural Equation Models to identify the best fitting model, and subsequently tested in Rio de Janeiro (n = 1,075) via CFA. Alternative reduced versions were further explored using the aggregate sample. Model-based Item Response Theory (IRT) location parameters were also investigated.
An absence of factor-based convergent and discriminant validity rejected the original proposition. However, the one-dimensional structure still held several residual correlations. Further exploration indicated the sustainability of reduced versions with seven (alternative A) and six (alternative B) items. Both presented excellent fit and no relevant residual item correlation. According to the IRT location parameters, items in alternative B covered a wider range of the latent trait. The Loevinger's H scalability coefficients underscored this pattern.
The original model did not hold. A one-factor solution was the most tenable in both large samples, but with significant item residual correlations, indicating that content redundancies persisted. Further reduced and simplified versions of the TIS proved promising. Although studies are yet to be carried out in other settings, it is the authors' impression that the restricted versions of the TIS are already apt for use in epidemiologic studies since the pros tend to outweigh the cons (as outlined in the Discussion section).
强直静止是在极端恐惧情况下出现的一种运动抑制的临时状态。最初为评估强直静止而开发的量表是10项强直静止量表（TIS）。然而，关于其结构（维度）效度的研究仍然很少。本研究的目的是重新评估应用于巴西两个大城市遭受一般创伤的代表性样本的TIS的因子结构。
样本包括3223名报告至少有一次创伤经历的参与者。在圣保罗（n = 2148），验证性因子分析（CFA）首先测试最初提出的二维结构。随后进行顺序探索性结构方程模型以确定最佳拟合模型，随后在里约热内卢（n = 1075）通过CFA进行测试。使用总体样本进一步探索替代简化版本。还研究了基于模型的项目反应理论（IRT）位置参数。
缺乏基于因子的收敛效度和区分效度，否定了最初的命题。然而，一维结构仍然存在一些残余相关性。进一步探索表明，七个项目（替代方案A）和六个项目（替代方案B）的简化版本具有可持续性。两者都具有良好的拟合度，且没有相关的残余项目相关性。根据IRT位置参数，替代方案B中的项目涵盖了更广泛的潜在特质范围。洛温杰H可扩展性系数强调了这种模式。
原始模型不成立。单因素解决方案在两个大样本中最具说服力，但存在显著的项目残余相关性，表明内容冗余仍然存在。TIS的进一步简化版本证明很有前景。尽管尚未在其他环境中进行研究，但作者的印象是，TIS的简化版本已经适用于流行病学研究，因为其优点往往超过缺点（如讨论部分所述）。
