When are item response models consistent with observed data?

The problem of deciding whether a set of mental test data is consistent with any one of a large class of item response models is considered. The classical assumption of locla independence is weakened to a new condition, local nonnegative dependence (LND). Necessary and sufficient conditions are derived for a LND item response model to fit a set of data. This leads to a condition that a set of data must satisfy if it is to be representable by any item response model that assumes both local independence and monotone item characteristic curves. An example is given to show that LND is strictly weaker than local independence. Thus rejection of LND models implies rejection of all item response models that assume local independence for a given set of data.This research was supported in part by Grant NIE-G-78-0157 to ETS from the NIE, by the Program Statistics Research Project, and by TOEFL Program Research. I would like to thank Dr. Douglas Jones of ETS for stimulating discussions during the early stages of this research, Dr. Frederick Lord of ETS for his encouragement of this work and comments on earlier drafts of this paper and Professor Robert Berk of Rutgers University for pointing out that conditions (a), (b) and (c) of Theorem 2 were also sufficient for LND and Monotonicity. Dr. Donald Alderman of ETS provided financial support for the development of a computer program to apply these results to data from the TOEFL program.     

The relationship of depression and somatic focus to experimental and clinical pain in chronic pain patients

Abstract

The present study examined Fields' proposal that depression increases the sensory experience of pain in part through greater somatic focus. Experimental and clinical pain measures were compared to self-report of depression and somatic focus in 60 chronic pain patients. Depression scores were unrelated to pain threshold or tolerance on the cold-pressor test. However, as hypothesized by Fields, path analytic models suggested that depression had a direct influence on the evaluative and affective aspects of pain, but the relationship between depression and sensory pain was mediated by somatic focus. These results provide partial support for Fields' neurobiological model of pain and depression.     

基于神经生理学的疼痛测量

疼痛是一种受多重因素影响的复杂主观感受。临床上,疼痛测量主要依赖于患者的主观评价。然而,这种传统的疼痛测量方法具有多方面的局限。近年来,研究者借助生理记录、脑电和功能磁共振等技术,揭示疼痛的神经生理、心理机制,挖掘与疼痛相关的神经生理指标,进而构建有效、客观和精确的疼痛评价体系。在基础研究和临床实践中,这些技术有望弥补传统疼痛测量方法的不足,从而极大推动疼痛测量及其治疗等相关领域研究的发展。     

Use of verbal pain measurement in the detection of hidden psychological morbidity among low back pain patients with objective organic findings

Abstract

Patients with positive physical findings to explain low back pain arc believed lo belong to two organic subgroups. One group has organic disease alone: in the other, organic disease is accompanied by psychological disturbance. Separation of patients with medical findings into groups with varying levels of psychological disturbance is difficult, because emotional disturbance is often hidden. In this study, the pain report of 124 patients with organic findings alone, and 50 patients with organic and psychological findings was examined to determine whether pain measurement could he used to identify accurately patients belonging 10 the two groups. the pain groups differed in the use of 43 pain words from the Low Back Pain Symptom Check List. Using a set of weights derived From discriminant analysis. the 33 pain words predicted 99.2% of the patients with organic disease alone and 86.0% of the patients with organic disease and psychological disturbance. The results were replicated in a new sample of 140 patients. Cross-validation shrinkage in accuracy was 8.3%. The results of the two studies suggest that pain measurement may he a useful clinical indicator of psychological disturbance in patients with organic findings.     

Chronic pain,compensation and clinical knowledge

The nosological status of the putative clinical entity of compensation neurosis and the relationship of chronic pain complaints to compensation are explored. It is concluded that, using the traditional criteria of diagnostic validity, there is no support for the view that a specific type of psychiatric disorder related to compensation or litigation can be demonstrated. Although it has been generally considered that chronic pain complaints reflect an underlying disease state, recent evidence has shown that in the medico-legal setting the nature of the compensation system and the level of available benefits have a marked influence on both the rate of chronic pain complaints and the duration of pain related work incapacity.     

Stiffness properties of the trunk in people with low back pain

The purpose of this study was to examine the dynamic properties of the trunk during unstable sitting and to determine differences between healthy and low back pain (LBP) participants.Participants sat on a custom-made chair that was able to swing freely in the sagittal plane. The chair was mounted on a force platform to measure loads acting at the trunk. Each participant was asked to find a balanced position after the chair was tilted backward and released. Movements of the trunk and chair were recorded. Effective moment of inertia, stiffness and damping coefficients were derived using a second order linear model. 10 participants were re-tested to assess reliability.Trunk stiffness was found increased for LBP subjects (p < .05) while no difference was found for damping coefficient. Gender and initial tilt angle did not affect viscoelastic properties of the spine.A second order linear model adequately described the biomechanical response of the trunk. It was shown that the trunk response was mainly elastic for all participants. The increase in trunk stiffness in LBP subjects could be a compensatory strategy to decrease pain and the risk of further injuries, but further investigations are needed to understand the nature of the viscoelastic alterations.     

疼痛恐惧的形成及其对疼痛知觉的影响

脑岛、杏仁核是疼痛恐惧形成的重要神经网络中心。疼痛恐惧增强了慢性疼痛患者的疼痛知觉体验, 进而加剧抑郁、焦虑情绪和功能损伤程度。脑岛、杏仁核、前额皮层和前扣带回是疼痛恐惧影响疼痛知觉的重要神经基础。通过认知方法干预疼痛恐惧可以改善患者的抑郁、焦虑情绪, 减少功能损伤。未来研究应拓展疼痛恐惧的测量工具, 采用功能磁共振成像技术进一步揭示疼痛恐惧影响慢性疼痛患者疼痛知觉的神经机制。     

Anxiety sensitivity and its impact on pain experiences and conditions: A state of the art

This paper serves as an introduction to the special issue of Cognitive Behaviour Therapy devoted to the topic of anxiety sensitivity (AS) and its impact on pain experiences and conditions. We provide a historical overview of relevant cognitive behavioural models of chronic pain, summarize recent models incorporating the AS construct, and introduce the papers in the special issue. These papers are organized into two sets – basic laboratory‐based investigations and relatively more applied studies. We attempt to highlight some of the most important findings from each of these investigations and studies, in turn. Then, we consider several important conclusions derived from the set of special issue papers and the implications of these for the practice of cognitive‐behavioural interventions with pain populations. Finally, we make several suggestions for directions for future investigations in this burgeoning area of cognitive behavioural research and practice.     

婴儿的痛觉

婴儿痛觉对婴儿的生长发育有重要意义, 已经日益引发研究者的兴趣。痛觉本质上是一种不愉悦的感官和情绪体验, 是通过早年与伤害有关的经历习得的。在心理学角度, 在介绍婴儿痛觉概念、神经生理机制、评估工具的基础上, 系统梳理痛觉对婴儿生长发育的影响及其影响因素十分必要。后续研究需继续完善婴儿痛觉的测量方法, 考察疼痛反应在不同文化和不同群体间的差异。     

The impact of experiential avoidance on the relations between illness representations,pain catastrophising and pain interference in chronic pain

Objective: The aim of this study was to examine the effects of experiential avoidance (EA) on the indirect relationship of chronic pain patients’ illness representations to pain interference, through pain catastrophising

Design and main outcome measure: The sample consisted of 162 patients diagnosed with an arthritis-related or a musculoskeletal disorder. The effects of EA on the pathway between illness representations, pain catastrophising and pain interference were examined with PROCESS, a computational tool for SPSS

Results: After controlling for patient and illness-related variables and pain severity, the ‘illness representations–pain catastrophising–pain interference’ pathway was interrupted at the higher levels of EA. The reason was that, at the high levels of EA, either the relation of illness representations to pain catastrophising or the relation of pain catastrophising to pain interference was not statistically significant.

Conclusion: The findings indicate that EA is not a generalised negative response to highly aversive conditions, at least as far as the factors examined in this study are concerned. EA may rather reflect a coping reaction, the impact of which depends on its specific interactions with the other aspects of the self-regulation mechanism. At least in chronic pain, EA should become the focus of potential intervention only when its interaction with the illness-related self-regulation mechanism results in negative outcomes.     

The pain behavior scale: Modification and validation for outpatient use

The present study investigated the validity of an inpatient pain behavior rating scale modified for outpatient use. A series of 43 consecutive outpatients referred for evaluation of chronic pain was examined using the Pain Behavior Scale (PBS) and other psychometric instruments. Analyses revealed significantly higher Pain Behavior Scale scores for low back and multiple pain-site groups. The results also indicated a high degree of internal consistency of the scale. A multiple regression analysis, predicting observed pain behavior from reported pain behavior, indicated that decreased activity accounted for 32% of the variance in the PBS score. A similar regression for pain experience found that the pain level and the sensory scale score on the McGill Pain Questionnaire accounted for 39% of the PBS variance. Psychological characteristics including disease conviction, self-control, depression, and anxiety explained 45% of the variability in the PBS score. Thus, the scale is related to pain intensity, interference with activities, and a variety of psychological characteristics. The scale provides a measure of observable pain behavior that is also relatively independent of these clinical data sources. The Pain Behavior Scale as modified for outpatient use provides a brief index of pain behavior with potential use in the comprehensive evaluation of the pain patient.     

The role of pain behaviour and family caregiver responses in the link between pain catastrophising and pain intensity: A moderated mediation model

Objectives: This study investigated the mediating role of pain behaviours in the association between pain catastrophising and pain intensity and explored the moderating role of family caregivers’ responses to pain in the link between pain behaviours and pain intensity.

Methods: The sample consisted of 154 chronic pain patients and their family caregivers. Patients completed questionnaires regarding pain intensity, pain catastrophising, pain behaviours and their caregivers’ responses to their pain. Family caregivers reported their responses to the patients’ pain.

Results: Pain catastrophising was associated with pain intensity (r = 0.37) and pain behaviours partly mediated this association. The positive association between pain behaviours and pain intensity was significant only if patients reported that their family caregivers showed high levels of solicitous (effect = .49) and distracting responses (effect = .58), and if caregivers reported to show high levels of solicitous responses (effect = .51). No support was found for negative responses as a moderator neither based on patients’ perception of negative responses nor based on caregivers’ perception of negative responses.

Conclusions: The findings are in line with the idea that family caregivers’ solicitous and distracting responses convey to patients that their condition is serious, which may reinforce patients’ pain and pain behaviours, especially in those who catastrophise.     

Neural basis of affective touch and pain: A novel model suggests possible targets for pain amelioration

Pain is one of the most common health problems and has a severe impact on quality of life. Yet, a suitable and efficient treatment is still not available for all patient populations suffering from pain. Interestingly, recent research shows that low threshold mechanosensory C-tactile (CT) fibres have a modulatory influence on pain. CT-fibres are activated by slow gentle stroking of the hairy skin, providing a pleasant sensation. Consequently, slow gentle stroking is known as affective touch. Currently, a clear overview of the way affective touch modulates pain, at a neural level, is missing. This review aims to present such an overview. To explain the interaction between affective touch and pain, first the neural basis of the affective touch system and the neural processing of pain will be described. To clarify these systems, a schematic illustration will be provided in every section. Hereafter, a novel model of interactions between affective touch and pain systems will be introduced. Finally, since affective touch might be suitable as a new treatment for chronic pain, possible clinical implications will be discussed.     

抑制功能在疼痛中的作用

自生物心理社会模型提出以来, 利用心理因素预防和治疗疼痛备受关注, 越来越多的研究表明抑制功能在疼痛发展和恢复阶段起关键作用。疼痛诱发的自我防御机制通过争夺认知资源影响抑制功能, 反之低抑制功能个体在应对疼痛干扰中表现较差, 进而影响着疼痛的预期和学习。现有关于抑制功能影响疼痛的研究主要基于相关设计, 未来应进一步明确二者的因果关系。深入理解疼痛与抑制功能相互作用的认知机制有助于指导抑制功能对慢性疼痛的靶向干预。     

Negative beliefs about low back pain are associated with persistent high intensity low back pain

While previous cross-sectional studies have found that negative beliefs about low back pain are associated with pain intensity, the relationship between back beliefs and persistent low back pain is not well understood. This cohort study aimed to examine the role of back beliefs in persistent low back pain in community-based individuals. A hundred and ninety-two participants from a previous musculoskeletal health study were invited to take part in a two-year follow-up study. Beliefs about back pain were assessed by the Back Beliefs Questionnaire (BBQ) at baseline and low back pain intensity was measured by the Chronic Pain Grade Questionnaire at baseline and follow-up. Of the 150 respondents (78.1%), 16 (10.7%) reported persistent high intensity low back pain, 12 (8.0%) developed high intensity low back pain, in 16 (10.7%) their high intensity low back pain resolved and 106 (70.7%) experienced no high intensity low back pain. While participants were generally positive about low back pain (BBQ mean (SD) = 30.2 (6.4)), those with persistent high intensity pain reported greater negativity (BBQ mean (SD) = 22.6 (4.9)). Negative beliefs about back pain were associated with persistent high intensity low back pain after adjusting for confounders (M (SE) = 23.5 (1.6) vs. >30.1 (1.7), p < .001). This study found negative back beliefs were associated with persistent high intensity low back pain over 2 years in community-based individuals. While further longitudinal studies are required, these findings suggest that targeting beliefs in programs designed to treat and prevent persistent high intensity low back pain may be important.     

疼痛背景下时距知觉的变化

时距知觉指对数百毫秒到数个小时时长的知觉, 是日常生活中许多活动的基础。时距知觉受到相当多因素的影响, 如唤醒、注意、动机等。疼痛是一种多维度的心理及生理现象, 包含有感觉分辨、情绪动机、认知评价三个成分。近期研究证明时距知觉会在疼痛背景下发生改变。疼痛背景下时距知觉的相关研究主要涉及三个方面：(1)健康被试对疼痛面孔的时距知觉; (2)实验室诱发疼痛对健康被试时距知觉的影响; (3)临床疼痛患者的时距知觉变化。探索疼痛背景下时距知觉的变化, 可以为理解疼痛的发生发展机制以及时间知觉的机制提供一个新视角。