Autocorrelation of choice-reaction times.

A choice-reaction (CR) task requires that the subject estimate, raking the warning signal or his response on the preceding trial as a reference point, the time when the reaction stimulus is due, so that he can begin deciding on his response at an appropriate time. This paper presents a model for the reproduction of temporal intervals, with particular emphasis on the sequential statistics of a series of such reproductions. When this model is concatenated with the sequential probability ratio test model for 2CRT, it provides a quantitative account of the pattern of autocorrelation found in a series of RTs. There is no corresponding autocorrelation in the incidence of errors, however, because after an error the subject systematically adjusts the epoch at which he begins sampling as a precaution against a further error. These post-error adjustments can readily be incorporated into the model. The ideas presented enable several different CR phenomena to be related, and they have implications for the relation between speed and accuracy, for the form of empirical distributions of RTs, and for the effects of temporal uncertainty.     

Pain: Biopsychosocial Mechanisms and Management

Traditionally, pain has been viewed as a sensory event warning of tissue damage or illness. This explanation fails to account for many of the experiences of people suffering from clinically painful conditions. Over the past two decades, a new biopsychosocial perspective on pain has emerged. This perspective emphasizes that pain is a dynamic process that not only is influenced by biological, psychological, and social mechanisms of pain, but also produces biological, psychological, and social changes that can affect future responses to pain. This review presents findings from recent studies of the biological, psychological, and social mechanisms of pain and discusses the implications of these findings for pain research, assessment, prevention, and treatment, as well as for health care policy.     

Relationship between the Millon Behavioral Health Inventory and the minnesota multiphasic personality inventory (MMPI) in low-back pain patients

The Millon Behavioral Health Inventory (MBHI) is being used with increasing frequency for the assessment of chronic pain, although there is a relative lack of evidence as to its utility, and prior studies have not examined low back pain. This investigation compared the MBHI to the MMPI in a sample of low-back pain patients and analyzed subgroups of pain patients based upon their MBHI responses. Subjects were 60 patients who had been admitted to outpatient multidisciplinary pain clinics of two Chicago-area hospitals. Patients completed both the MMPI and the MBHI and provided demographic information. Results of correlational analyses indicated strong relationships between the MBHI psychogenic attitude, psychosomatic correlate, and prognostic index scales and the validity scales of the MMPI. The MBHI Pain Treatment Responsivity scale (PP) correlated with 16 of the other 19 MBHI scales. PP did not demonstrate specificity with low back pain patients. The results of both the scale comparisons and the exploratory two-group cluster subgroup analysis support the notion that responses to the MBHI are largely affected by the respondent's tendency to deny psychopathology or to admit emotional distress.     

What is chronic pain?

Chronic pain leads to individual suffering and to major costs for all developed countries. Previous studies suggest that both the incidence of disabling chronic pain and the amount of health care consumption due to chronic pain are rapidly increasing. Western medicine is not only often ineffective but may be one of the causes of this epidemic. This article will address the issue of chronic pain of unknown etiology and has the goals of: (1) identifying the factors which have led to our confusion about this topic, and (2) proposing alternative ways of conceptualizing chronic pain and its ensuing behaviors and social consequences. It is concluded that it is essential to discriminate between tissue damage, pain, suffering, pain behaviors, health care consumption, impairment and disability if one is to develop a meaningful conceptualization of the medical, social, economic and political problems of chronic pain. Successful treatment must be defined in behavioral terms such as restoration of normal activities. Disabling chronic pain is often a sign of overwhelming stress engendered by the individual's failure to cope with the demands of industrialized society.     

PTSD and Emotional Distress Symptoms Measured After a Motor Vehicle Accident: Relationships with Pain Coping Profiles

This study explored differences among pain patients classified as Dysfunctional, Interpersonally Distressed, and Adaptive Copers on the Multidimensional Pain Inventory with respect to PTSD symptomatology, anxiety, and depression. Eighty-five patients with pain complaints who had experienced a serious motor vehicle accident were classified into these three pain coping categories and assessed using clinician and self-report measures. Results indicated that patients classified as Adaptive Copers (n = 24) showed less PTSD symptomatology, anxiety, and depressed mood, relative to individuals classified as Dysfunctional (n = 36) and as Interpersonally Distressed (n = 25), who did not differ on these dimensions. Emotional responses during the accident (fear, helplessness, danger, perceived control, and certainty that one would die) did not differentiate the groups. Pain profiles contributed to the prediction of self-reported PTSD symptoms, controlling for state anxiety. These data suggest that pain patients with both Dysfunctional and Interpersonally Distressed coping profiles are at elevated risk for a range of posttrauma problems following a serious motor vehicle accident.     

Is pain-related fear a predictor of somatosensory hypervigilance in chronic low back pain patients?

Pain-related fear has been found to be associated with increased disability and increased pain perception in patients with chronic low back pain. A possible mechanism by which pain-related fear could lead to increased pain perception is heightened attention to somatosensory sensations. In the present study, chronic pain patients reporting either a high or low level of pain related fear and control participants performed an auditory reaction time task, while occasionally non-painful electrical stimuli--accompanied by threatening instructions--were given to the arm or back. In the primary task condition, participants had to perform the auditory task while ignoring the electrical stimuli. Next, the task was presented under dual task conditions in which participants had to respond both to tones as well as to detection of electrical stimuli. It was hypothesized that for the primary task, high fearful patients would show greater disruption of performance on the auditory task than low fearful patients and controls when stimuli were presented to the back. For the dual task, slower reaction times for the auditory task, in combination with faster detection of electrical stimuli was expected. The hypotheses were not confirmed but patients scoring high on pain-related fear did show an overall increase in reaction time for all conditions of the primary task, with or without simultaneous stimulation. Regression analyses demonstrated that high pain-related fear was associated with increased reaction time to tones both in patients and healthy controls, and that within patients pain-related fear was a better predictor of reaction time to tones than present pain intensity. The findings may be interpreted as showing that patients with elevated levels of pain-related fear habitually attend to somatic sensations, giving less priority to other attention-demanding tasks.     

处理疼痛的理念

处理疼痛的理念各有不同。有人认为手术后疼痛很正常,挺着吧。人老了,腰腿痛就该扛着。而有的人会积极给予止痛治疗,以患者舒适为目标。2007年7月我国卫生部签发了关于《医疗机构诊疗科目名录》中增加“疼痛科”的文件,说明我国进入了一个止痛治疗的新时代。得到疼痛治疗是患者的基本权利,也是医师的崇高职责。有疼有痛忍着不治的时代即将过去,及早、及时为患者止痛是人道主义的体现。     

The contribution of recollection and familiarity to recognition memory performance in chronic pain patients

This study examines the selective impact of chronic pain on memory functioning in a recognition task. Thirty chronic pain patients and 30 healthy control subjects performed a yes-no word recognition test. The contribution of recollection and familiarity to both groups' performance was compared by means of the Remember/Know (R/K) procedure, which distinguishes recognition based on the recollection of the encoding episode (R responses) and recognition accompanied by a feeling of familiarity (K responses). Chronic pain patients showed a decrease in recollection together with an increase in familiarity: indeed, they reported less R and more K responses than control subjects. This pattern of performance was not related to the overall recognition ability. These findings are consistent with the hypothesis of the attentional cost of chronic pain, suggesting a selective impact of chronic pain on the most attention-demanding cognitive processes, such as recollection. This study emphasises the relevance of specific procedures distinguishing the underlying components of memory functioning rather than solely global indicators.