Speech motor control and chronic back pain: a preliminary investigation.

OBJECTIVES: Chronic back pain and its sequelae can influence cognitive, affective, and neuromuscular functioning. Speech production--a complex sensorimotor activity--integrates shared cognitive, neuromuscular, and musculoskeletal resources, and therefore could be altered by chronic pain. The purpose of this preliminary investigation was twofold: 1) to determine whether speech alternating motion rates (i.e., speech AMRs) which require rapid, reciprocally coordinated articulatory movements were associated with chronic back pain; and 2) to identify factors that might mediate any observed alterations. DESIGN: Fifty participants, fully or partially disabled by chronic back pain, completed standardized protocols related to pain, depression, disability, medications, as well as speech AMRs. RESULTS: Higher levels of back pain were significantly associated with slower speech AMRs. Stepwise multiple regression assessed the unique and cumulative effects of specific variables such as degree of back pain, depression, level of disability, and medication use on speech motor performance. Speech motor slowness was uniquely related to back pain and the use of nonprescription pain medications, but not to level of depression or disability. CONCLUSIONS: Chronic back pain independently influences speech motor rates. Several explanatory models are proposed including pain-induced centrally mediated motor retardation/inhibition, reduced selective attention, and peripherally based "bracing/holding" of shared musculoskeletal environments.

Postoperative pain patterns in chronic pain patients: a pilot study.

OBJECTIVE: This exploratory investigation compared patterns of postoperative pain over 6 days in normal patients recovering from surgery with those of patients using opioid medications for chronic pain. It tested the following hypotheses: 1) Chronic pain patients have a different pattern of postoperative pain than normals; 2) Women have a different pattern of postoperative pain resolution than men. PATIENTS: Normal (N = 96) and chronic pain (N = 42) patients undergoing surgery served as subjects. DESIGN: The study employed a linear mixed effects model to compare repeated measures of pain in the two patient groups. OUTCOME MEASURES: Patients rated pain daily following surgery over 6 days. Each patient's pain pattern is a linear trend having an intercept (initial pain level) and a slope (rate of pain change over days). RESULTS: The chronic pain patients initially reported a higher mean pain level, and they differed from normal patients in their average postoperative pain patterns (P < 0.001), as did men and women (P = 0.039). Whereas normals decreased in pain report over the 6 days of recovery at an average rate of -0.35 units per day, chronic pain patients changed at an average rate of only -0.06 units per day (P < 0.001). Women began at day 0 with greater average pain than men (6.15 vs 5.16, P = 0.029) but resolved their pain more rapidly (-0.291 points per day vs -0.118 points per day, P = 0.017). CONCLUSIONS: Surgical patients who have chronic pain and use opioid medications for that pain have more postoperative pain than normals and resolve that pain more slowly.

Improving perioperative pain management: a preintervention and postintervention study in 7 developing countries.

INTRODUCTION: The burden of untreated postoperative pain is high. OBJECTIVE: This study assessed feasibility of using quality improvement (QI) tools to improve management of perioperative pain in hospitals in multiple developing countries. METHODS: The International Pain Registry and Developing Countries working groups, from the International Association for the Study of Pain (IASP), sponsored the project and PAIN OUT, a QI and research network, coordinated it, and provided the research tools. The IASP published a call about the project on its website. Principal investigators (PIs) were responsible for implementing a preintervention and postintervention study in 1 to 2 surgical wards in their hospitals, and they were free to choose the QI intervention. Trained surveyors used standardized and validated web-based tools for collecting findings about perioperative pain management and patient reported outcomes (PROs). Four processes and PROs, independent of surgery type, assessed effectiveness of the interventions. RESULTS: Forty-three providers responded to the call; 13 applications were selected; and PIs from 8 hospitals, in 14 wards, in 7 countries, completed the study. Interventions focused on teaching providers about pain management. Processes improved in 35% and PROs in 37.5% of wards. CONCLUSIONS: The project proved useful on multiple levels. It offered PIs a framework and tools to perform QI work and findings to present to colleagues and administration. Management practices and PROs improved on some wards. Interpretation of change proved complex, site-dependent, and related to multiple factors. PAIN OUT gained experience coordinating a multicentre, international QI project. The IASP promoted research, education, and QI work.

Pain and stress in a systems perspective: reciprocal neural, endocrine, and immune interactions.

UNLABELLED: This paper advances a psychophysiological systems view of pain in which physical injury, or wounding, generates a complex stress response that extends beyond the nervous system and contributes to the experience of pain. Through a common chemical language comprising neurotransmitters, peptides, endocannabinoids, cytokines, and hormones, an ensemble of interdependent nervous, endocrine, and immune processes operates in concert to cope with the injury. These processes act as a single agent and comprise a supersystem. Acute pain in its multiple dimensions, and the related symptoms that commonly occur with it, are products of the supersystem. Chronic pain can develop as a result of unusual stress. Social stressors can compound the stress resulting from a wound or act alone to dysregulate the supersystem. When the supersystem suffers dysregulation, health, function, and sense of well-being suffer. Some chronic pain conditions are the product of supersystem dysregulation. Individuals vary and are vulnerable to dysregulation and dysfunction in particular organ systems due to the unique interactions of genetic, epigenetic and environmental factors, as well as the past experiences that characterize each person. PERSPECTIVE: Acute tissue injury activates an ensemble of interdependent nervous, endocrine, and immune processes that operate in concert and comprise a supersystem. Some chronic pain conditions result from supersystem dysregulation. Individuals vary and are vulnerable to dysregulation due to the unique interactions of genetic, epigenetic, and environmental factors and past experiences that characterize each person. This perspective can potentially assist clinicians in assessing and managing chronic pain patients.

Emotional disclosure through patient narrative may improve pain and well-being: results of a randomized controlled trial in patients with cancer pain.

Narrative medicine is based upon physicians' awareness of patients' narration of their suffering, their hopes, and how illness has affected them. It offers a model for improving health outcomes. To determine whether incorporating a narrative approach in patients with cancer decreases pain intensity and improves their global sense of well-being, we performed a randomized, single-blind controlled trial in adult patients with cancer and average pain intensity levels of at least 5/10. Two hundred thirty-four patients were randomized into three groups: (1) narrative (n=79), in which patients wrote a story about how cancer affected their lives for at least 20 minutes once a week for three weeks; (2) questionnaire (n=77), in which patients filled out the McGill Pain Questionnaire; and (3) control (n=78), in which patients came weekly to medical visits during which they received usual customary care. Patients rated their pain on a 0-10 scale and their well-being on a seven-point Likert scale weekly for eight weeks. Two raters independently evaluated the emotional content of the narratives. Pain intensity and sense of well-being were similar in all groups before and after treatment. Subgroup analyses showed that patients whose narratives had high emotional disclosure had significantly less pain and reported higher well-being scores than patients whose narratives were less emotional. Further study is needed to demonstrate whether the implementation of narrative medicine is associated with health benefits in this and other contexts.

Progress in pain assessment: the cognitively compromised patient.

PURPOSE OF REVIEW: Pain assessment is essential for patient care in many settings, but it proves difficult when the patient is cognitively compromised or otherwise unable to produce a conventional pain report. The present review describes the progress in pain assessment technology that involves the coding of human facial expression. RECENT FINDINGS: It is possible to quantify facial expression by coding patterns of facial muscle contraction and relaxation. These patterns are action units, and they can gauge the intensity of pain as well as signal its occurrence. The experience of pain seems to generate a unique facial expression comprising several action units. Concerns have existed about whether demented patients produce diagnostically meaningful facial expressions of pain because they tend to generate more nonspecific facial expressions and perhaps code pain intensity less well than normals. Recent work shows that facial expression reflects pain as well or better in demented patients compared with normals. SUMMARY: Although still nascent, coded facial expression appears to work reliably as a pain assessment tool with cognitively compromised patients. Clinical application awaits the development of technology that can automate facial coding and scoring.

Prospective evaluation of chronic pain disorders and treatments.

BACKGROUND: The incidence of chronic pain is variable among individuals who have sustained traumatic or surgical injury. Also, treatments for pain rarely are effective consistently for a procedure or agent, and no therapies are considered effective for pain that is chronic. NEW METHOD: Difficulties with standard methods for conducting clinical trials call attention to a need for protocols that provide a new understanding of the development of and control over chronic pain. Prospective single-subject research designs can document varieties of pain progression over time for individuals. Subsequent grouping of individuals with common characteristics directs a mechanism-based approach to therapy. RESULTS: Tracking of individuals' pain and associated influences over time is consistent with clinical practice, noting and adapting to changes that occur. COMPARISON WITH EXISTING METHODS: Grouping patients with diverse characteristics and variable effects of therapy is problematic. Conventional evaluation of pain assesses patients with similar injuries or surgery without characterizations of individuals who develop chronic pain or recover over time. Also, classical evaluation of therapies involves comparison of groups receiving treatment or a placebo without characterization of patients with successful and unsuccessful results. CONCLUSIONS: Single-subject prospective studies can inform clinical trials according to individual differences that would be obscured by comparison of groups with unknown variation in characteristics that influence pain and therapeutic effectiveness.

Pupil dilation response to noxious stimulation: effect of varying nitrous oxide concentration.

OBJECTIVE: This report examines the pain-related pupil dilation response (PDR), tracking it across mixture concentrations of nitrous oxide (N(2)O) in oxygen (O(2)) and relating its variation to change in long latency somatosensory evoked potentials (SEPs) and visual analogue scale (VAS) pain report. METHODS: We varied mixture concentrations of N(2)O in O(2) (0%, 10%, 30%, and 50%), measuring PDR, SEP and VAS responses to painful electrical fingertip stimulation at high and low intensities in 15 volunteers. RESULTS: Mixed effect model statistical analyses revealed that: (1) PDR increased significantly with stimulus intensity and constricted significantly with mixture concentration; (2) SEP and VAS decreased significantly with increasing mixture concentration; (3) PDR correlated with SEP amplitude and VAS across mixture concentrations; (4) subjects differed significantly in: (a) baseline PDR and SEP amplitudes, (b) rate of change of these measures across mixture concentrations; and (5) VAS increased significantly with stimulus intensity and decreased significantly with mixture concentration without significant individual differences. CONCLUSIONS: The findings support the hypothesis that the pain-related PDR is a complex brain-mediated response rather than a simple sympathetic reflex. SIGNIFICANCE: PDR may provide a useful indicator for studying the central processing of noxious stimuli and the effects of analgesic interventions.

The Transition of Acute Postoperative Pain to Chronic Pain: An Integrative Overview of Research on Mechanisms.

The nature of the transition from acute to chronic pain still eludes explanation, but chronic pain resulting from surgery provides a natural experiment that invites clinical epidemiological investigation and basic scientific inquiry into the mechanisms of this transition. The primary purpose of this article is to review current knowledge and hypotheses on the transition from acute to persistent postsurgical pain, summarizing literature on clinical epidemiological studies of persistent postsurgical pain development, as well as basic neurophysiological studies targeting mechanisms in the periphery, spinal cord, and brain. The second purpose of this article is to integrate theory, information, and causal reasoning in these areas. Conceptual mapping reveals 5 classes of hypotheses pertaining to pain. These propose that chronic pain results from: 1) persistent noxious signaling in the periphery; 2) enduring maladaptive neuroplastic changes at the spinal dorsal horn and/or higher central nervous system structures reflecting a multiplicity of factors, including peripherally released neurotrophic factors and interactions between neurons and microglia; 3) compromised inhibitory modulation of noxious signaling in medullary-spinal pathways; 4) descending facilitatory modulation; and 5) maladaptive brain remodeling in function, structure, and connectivity. The third purpose of this article is to identify barriers to progress and review opportunities for advancing the field. This review reveals a need for a concerted, strategic effort toward integrating clinical epidemiology, basic science research, and current theory about pain mechanisms to hasten progress toward understanding, managing, and preventing persistent postsurgical pain. PERSPECTIVE: The development of chronic pain after surgery is a major clinical problem that provides an opportunity to study the transition from acute to chronic pain at epidemiologic and basic science levels. Strategic, coordinated, multidisciplinary research efforts targeting mechanisms of pain chronification can to help minimize or eliminate persistent postsurgical pain.

National Institutes of Health grant awards for pain, nausea, and dyspnea research: an assessment of funding patterns in 2003.

UNLABELLED: We introduce an interactive database that permits description and exploration of National Institutes of Health (NIH) funding patterns for research on pain, nausea, and dyspnea. The database encompasses both basic science and clinical research. This article describes how we created the database, including the procedures we developed for reviewing and classifying research grants. In addition, it reports NIH grants and funding activity for the year 2003, with a breakdown of funding activity by Institute and funding comparisons across Institutes. It also describes a first attempt to identify clinically significant but underfunded research domains. In 2003, the NIH funded 1148 grants having relevance to the domain of pain, representing 2.5% of the total NIH research budget. Of those, 581 grants, or about 1% of the NIH budget, had a primary focus on pain. Of the diseases and conditions addressed by the current implementation, musculoskeletal conditions were the best represented with 105 grants, whereas cardiac conditions had the fewest number of grants with 7. The NIH funded 43 grants for dyspnea research and a scant 29 grants for nausea studies. We discuss the current limitations of the database and our plans for further development. PERSPECTIVE: The interactive database and classification system for pain, nausea, and dyspnea research funded by the NIH reported on in this article represents an objective and verifiable resource for health policy makers and others interested in NIH funding decisions. The high inter-rater reliability achieved attests to the objectivity of the classification method. Initial analyses demonstrate that these data can usefully track funding patterns by NIH institutes and reveal underfunded areas of research.

Pain and the defense response: structural equation modeling reveals a coordinated psychophysiological response to increasing painful stimulation.

The defense response theory implies that individuals should respond to increasing levels of painful stimulation with correlated increases in affectively mediated psychophysiological responses. This paper employs structural equation modeling to infer the latent processes responsible for correlated growth in the pain report, evoked potential amplitudes, pupil dilation, and skin conductance of 92 normal volunteers who experienced 144 trials of three levels of increasingly painful electrical stimulation. The analysis assumed a two-level model of latent growth as a function of stimulus level. The first level of analysis formulated a nonlinear growth model for each response measure, and allowed intercorrelations among the parameters of these models across individuals. The second level of analysis posited latent process factors to account for these intercorrelations. The best-fitting parsimonious model suggests that two latent processes account for the correlations. One of these latent factors, the activation threshold, determines the initial threshold response, while the other, the response gradient, indicates the magnitude of the coherent increase in response with stimulus level. Collectively, these two second-order factors define the defense response, a broad construct comprising both subjective pain evaluation and physiological mechanisms.

A psychophysiological causal model of pain report validity.

The validity of the pain report is vitally important but difficult to assess because pain is a personal experience. Human laboratory research affords an opportunity to investigate validity because one can measure the consistency and sensitivity of pain ratings produced in response to known stimuli. This article presents 2 levels of evidence characterizing the validity of the pain report measure. The within-subject agreement of pain report with known stimulus variation quantifies the criterion validity, or accuracy, of the measure. Causal modeling defines a second, between-subject, level of construct validity by suggesting a psychophysiological mechanism determining the observed individual variation in accuracy. We analyzed pain rating data obtained in a laboratory study where 100 subjects (56 men and 44 women) experienced varied levels of painful fingertip electrical stimulation, delivered in random order across 144 trials. Unknown to the subjects, there were only 3 stimulus intensities. Accuracy, defined operationally as the proportion of variance in pain report explained by stimulus level, ranged from 0.07 to 0.91 with a median of 0.64. Hypothesized determinants of accuracy comprised current intensity, event-related late near field evoked potentials, skin conductance response, heart rate, and pupil diameter change. We limited the evoked potential measures to the amplitude of the negative peak at 150 msec (N150amp) and combined the latter 3 measures to form a single index of overall sympathetic nervous system arousal (Arousal). Although men chose higher stimulus levels for the experiment and had higher Arousal than did women, their mean pain reports and their Accuracy did not differ from those of female subjects. We constructed a sequence of path analysis models designed to clarify the causal contributions of current intensity, N150amp, and Arousal, and to determine whether these relationships differ in men and women. The final model revealed a direct causal chain. Stimulus current determined the amplitude of N150amp (possibly an indicator of attention). N150amp in turn determined Arousal, and Arousal emerged as the sole determinant of the Accuracy of the pain report. In addition, this latter effect differed across the sexes. Men who experienced higher levels of Arousal gave more accurate pain reports than those who had lower levels, but women who had higher levels of Arousal gave less accurate pain reports than those with lower levels. Thus construct validation emerged, not from direct stimulus-response correlation, but from the elucidation of a causal chain that related stimulus to response.

Pain trajectory of Taiwanese with nasopharyngeal carcinoma over the course of radiation therapy.

The purpose of this study was to describe the characteristics and management of pain among patients with nasopharyngeal carcinoma (NPC) prior to and during the 7-week course of radiation therapy (RT) in Taiwan. Twenty-nine men and 11 women with NPC participated in this prospective, longitudinal study. A modified Brief Pain Inventory was used to assess pain and its interference with daily activities weekly. Medical records were reviewed to abstract pain management and disease data. Findings showed that the pain intensity and pain interference scores escalated prominently at Week 3 and peaked at Week 5, representing the time course of RT complications. Pain prior to RT exacerbated the RT-induced mucositis pain. The pain related to RT for NPC was often severe and undertreated, and affected swallowing and talking more than sleeping or other general activities. We recommend interventions to control pain be instituted prior to Week 3 to minimize the potentiation of subsequent pain.

Central noradrenergic mechanisms and the acute stress response during painful stimulation.

Events that threaten tissue integrity including noxious stimulation activate central noradrenergic circuits, particularly locus coeruleus and its projections. Recent advances in theory hold that an adaptive, defensive shift in brain activity takes place in response to threat. In principle, this shift may accentuate the autonomic and central biomarkers of the perception of painful events and the experience of pain itself. We have examined the effects of an alpha-2 agonist on pupil dilation responses, skin conductance responses, near field somatosensory evoked potentials and pain reports in normal volunteers undergoing repeated trials of painful fingertip stimulation delivered at low, medium and high intensities. In a double-blinded study, 114 healthy male and female volunteers underwent repeated noxious stimulation under baseline, placebo and active drug conditions where the active drug was the alpha-2 agonist tizanidine 4 mg. In contrast to baseline and placebo conditions, tizanidine 4 mg significantly reduced the magnitudes of the mean pupil dilation response, the mean skin conductance response, the mean near field somatosensory evoked potential peak-to-peak amplitude and the mean pain intensity rating. Stimulus intensity significantly altered all three biomarkers and the pain report in a graded fashion. There were no sex differences. These findings support the hypotheses that painful events activate central noradrenergic circuits, and that these circuits play a role in the autonomic and central arousal associated with pain.

Acute pain: effective management requires comprehensive assessment.

Pain is among the most common reasons that patients seek medical care, and inadequate assessment may result in suboptimal management. Acute pain in response to trauma or surgery can be complex, variable, and dynamic, but its assessment is often simplistic and brief. One-dimensional rating scale measures of pain severity facilitate rapid evaluation and often form the basis of treatment algorithms. However, additional features of pain should inform the selection of a treatment regimen, and can include pain qualities, duration, impact on functional capabilities, and underlying cause. Patient age, sex, psychosocial features, and comorbid conditions are also important features to consider. Use of a multidimensional tool is recommended for assessing many of these features if time permits. Additionally, clinicians often fail to recognize or consider the potentially detrimental long-term effects of acute pain. As the United States continues to experience a prescription drug crisis, a "universal precautions" approach including abuse risk assessment and abuse deterrence strategies should be implemented for patients receiving opioids. Increased efforts and research are necessary to enhance the utility of available acute pain assessment tools. Developing more comprehensive tools for patient assessment is the first step in achieving the ultimate goal of effective acute pain management. The objectives of this review are to summarize issues regarding the complexity of acute pain and to provide suggestions for its evaluation.

Opioid pharmacotherapy for chronic noncancer pain: the american experience.

Chronic noncancer pain is a significant and growing public health challenge in the United States. Lacking effective alternative interventions for effective chronic noncancer pain management, many physicians have turned to opioid pharmacotherapy. Increased opioid prescribing brings not only gains in therapeutic benefit but also a higher incidence of adverse drug events including increased medication misuse and opioid related mortality. Currently the United States must confront the dual problems of widespread undertreated chronic noncancer pain and a prescription opioid abuse crisis. Withholding pain relieving drugs from patients in need is unjustifiable, yet drug diversion, abuse and adverse drug events have become major social as well as medical problems. At the heart of this crisis is the lack of definitive evidence about the risk to benefit ratio of opioid pharmacotherapy for chronic noncancer pain both on an individual case and on a population basis. This article describes the extent and severity of the American chronic noncancer pain problem and the history of opioid pharmacotherapy for chronic noncancer pain in the United States. It then discusses the concept of evidence based practice and reviews current evidence supporting opioid pharmacotherapy for chronic noncancer pain as well as adverse drug events related to opioid pharmacotherapy including misuse and abuse. Finally, it considers the conflict of providing pain relief versus protecting society and reviews steps that governmental agencies, industry and others are taking to contain and ultimately resolve the problems of excessive prescribing and conflicting priorities.

Only modest long-term opioid dose escalation occurs over time in chronic nonmalignant pain management.

Clinical experience and the literature increasingly support differentiating chronic pain associated with malignant disease from chronic pain associated with nonmalignant conditions when defining optimal pharmacotherapy. The use of opioids for chronic nonmalignant pain has grown steadily despite the lack of a strong evidence base that can guide practice. A fundamental question is whether patients develop tolerance and need repeated dose escalations to sustain pain control. We examined opioid prescribing data from United Kingdom Clinical Practice Research Datalink longitudinal database of general practice records and tracked dose changes but not pain reports in a sample of 4035 patients who received oral or transdermal-extended release opioids for chronic nonmalignant pain. The median number of days on opioid pharmacotherapy for all patients was 311. Thirty percent of patients never changed doses during the course of treatment. In patients who never changed medications, the mean morphine equivalent 24-hour dose increased from beginning to end of opioid pharmacotherapy only by 1.4 fold, t = 25.73, Cohen's d = .427 and was independent of both age and gender. Comparison across extended release morphine, oxycodone, and fentanyl revealed that it was significantly greatest for patients using fentanyl and least for those using morphine.

Quality of postoperative pain management in American versus European institutions.

Management of postoperative pain remains an important clinical problem throughout the world. Using the PAIN-OUT acute pain registry database to examine perioperative pain management in orthopedic surgery patients, we compared patient-reported outcomes (PROs) in a pooled sample obtained from four American hospitals (N = 473) with PROs in a pooled sample of 20 European institutions (N = 8799). Most American hospitals consistently assess acute pain in surgical patients due to Joint Commission accreditation guidelines. Therefore, we hypothesized that this practice would create a climate of clinical staff sensitivity to patients' pain and a greater readiness to intervene when pain is higher than one would find in Europe as a whole. American institutions might then provide better control of postoperative pain after orthopedic surgery than European institutions. Because of the large sample sizes, our analyses focused on effect size rather than statistical significance. Evaluation of the pain PROs revealed that European patients reported much lower Worst Pain on the first day after orthopedic surgery than American patients. The mean Worst Pain (± SD) for Europeans was 5.4 (2.5) but for Americans the mean was 7.4 (2.7), p < .0001, a large effect size. Europeans also reported significantly less emotional discomfort, less interference of pain with activity and lower Least Pain. Nonetheless, 98.3% of American patients received opioids on the ward on the first postoperative day compared to 70.2% of European patients, and 41.1% received regional analgesia on the ward while 15.9% of European patients received regional analgesia (both small effect sizes). Overall, the results are clear in demonstrating much better pain control in the ensemble of European countries as compared to the United States.

Postoperative pain trajectories in cardiac surgery patients.

Poorly controlled postoperative pain is a longstanding and costly problem in medicine. The purposes of this study were to characterize the acute pain trajectories over the first four postoperative days in 83 cardiac surgery patients with a mixed effects model of linear growth to determine whether statistically significant individual differences exist in these pain trajectories, and to compare the quality of measurement by trajectory with conventional pain measurement practices. The data conformed to a linear model that provided slope (rate of change) as a basis for comparing patients. Slopes varied significantly across patients, indicating that the direction and rate of change in pain during the first four days of recovery from surgery differed systematically across individuals. Of the 83 patients, 24 had decreasing pain after surgery, 24 had increasing pain, and the remaining 35 had approximately constant levels of pain over the four postoperative days.

Resolution of acute pain following discharge from the emergency department: the acute pain trajectory.

UNLABELLED: We demonstrate and evaluate a method for modeling acute pain resolution in individual patients over 6 days following an emergency department visit for an acutely painful condition. Five hundred and thirteen patients presenting with acutely painful conditions provided 11-point numerical ratings of pain intensity at discharge from an emergency department and daily thereafter for a total of 6 days. Latent growth curve modeling with a linear fit yielded measures of initial pain intensity (intercept) and rate of pain resolution (slope) for each individual patient. The linear fits provided good approximations of individual pain trajectories. The average patient had intercept of 6.57 with a slope of -.61. On Day 4, 54.6% of patients reported a pain level equal to or greater than 4. Classification of individual patients by slope revealed that 79% of the sample had the expected negative slope for acute pain resolution while 21% had flat or positive slopes, indicating lack of pain resolution or worsening of pain over time following discharge. The standard errors of measurement for the acute pain trajectories were markedly smaller than those for conventional pain ratings, indicating that the trajectory approach to pain measurement improves measurement precision. PERSPECTIVE: The acute pain trajectory provides more information than conventional pain measurement and increases measurement precision. It provides a means of determining the efficacy of acute pain management in the emergency department. The rate of pain resolution is a potentially valuable outcome measure for controlled clinical trials.