Randy Neblett

The Development and Psychometric Validation of the Central Sensitization Inventory

Central sensitization (CS) has been proposed as a common pathophysiological mechanism to explain related syndromes for which no specific organic cause can be found. The term “central sensitivity syndrome (CSS)” has been proposed to describe these poorly understood disorders related to CS. The goal of this investigation was to develop the Central Sensitization Inventory (CSI), which identifies key symptoms associated with CSSs and quantifies the degree of these symptoms. The utility of the CSI, to differentiate among different types of chronic pain patients who presumably have different levels of CS impairment, was then evaluated. Study 1 demonstrated strong psychometric properties (test–retest reliability = 0.817; Cronbach’s alpha = 0.879) of the CSI in a cohort of normative subjects. A factor analysis (including both normative and chronic pain subjects) yielded 4 major factors (all related to somatic and emotional symptoms), accounting for 53.4% of the variance in the dataset. In Study 2, the CSI was administered to 4 groups: fibromyalgia (FM); chronic widespread pain without FM; work‐related regional chronic low back pain (CLBP); and normative control group. Analyses revealed that the patients with FM reported the highest CSI scores and the normative population the lowest (P < 0.05). Analyses also demonstrated that the prevalence of previously diagnosed CSSs and related disorders was highest in the FM group and lowest in the normative group (P < 0.001). Taken together, these 2 studies demonstrate the psychometric strength, clinical utility, and the initial construct validity of the CSI in evaluating CS‐related clinical symptoms in chronic pain populations. ▪

Quantifying the lumbar flexion-relaxation phenomenon: theory, normative data, and clinical applications.

Study Design. A two-part investigation was conducted: 1) a prospective study of asymptomatic subjects quantitatively comparing trunk mobility to surface electromyographic (sEMG) signals from the erector spinae during trunk flexion; and 2) a prospective repeated-measures cohort study of patients with chronic disabled work-related spinal disorder tested for the flexion–relaxation (FR) phenomenon while measured simultaneously for lumbar spine inclinometric range of motion (ROM). Objectives. To describe a theoretical model for the potential use of FR unloaded in assessing patients with chronic low back pain patients before and after rehabilitation, and to establish a normative database (Part 1) for subsequent use in comparison to patients with chronic low back pain (Part 2). The second part of the study assessed the clinical utility of combined sEMG and ROM measurements for assessing the FR phenomenon as a test to assist potentially in planning rehabilitation programs, guiding patients’ individual rehabilitation progress, and identifying early posttreatment outcome failures. Summary of Background Data. The FR phenomenon has been recognized since 1951, and it can be reproducibly assessed in normal subjects with FR unloaded. It can be found intermittently in patients with chronic low back pain. Recent studies have moved toward deriving formulas to identify FR, but only a few have examined a potential relation between inclinometric lumbar motion measures and the sEMG signal. No previous studies have developed normative data potentially useful for objectively assessing nonoperative treatment progress, effort, or the validity of permanent impairment rating measures. Methods. In Part 1, 12 asymptomatic subjects were evaluated in an intra- and interrater repeated-measures protocol to examine reliability of sEMG signal readings in FR, as well as ROM measures at FR and maximum voluntary flexion. The mean sEMG signal averaging right–left electrode recordings, as well as the gross, true, and sacral lumbar ROM measurements, were recorded as normative data. In Part 2, 54 patients with chronic disabled work-related spinal disorder referred as candidates for tertiary functional restoration rehabilitation participated in a standardized assessment protocol for sEMG and ROM measurement before rehabilitation. Those who completed the program were retested with the identical methodology after rehabilitation (n = 34) using the empirically derived cutoff scores for sEMG readings at FR and ROM from Part 1 and prior scientific literature. Pain disability self-reported scores were correlated with sEMG and ROM. Sensitivity and specificity of the sEMG for identifying abnormal motion were assessed. Results. In Part 1, the ability of the experienced testers to measure ROM and sEMG reliably at FR was high (r ≥ 0.92; P < 0.001). All asymptomatic subjects achieved FR at a tightly clustered range of mean sEMG signals from 1 to 2.3 &mgr;V. Most of the variation between motion at FR and maximum voluntary flexion occurred through the hip (sacral) motion component of the gross (or total) motion measured at T12. In Part 2, posttreatment reliability for ROM, sEMG, and the ability to detect the FR point was high (r ≥ 0.82; P < 0.001). More than 30% of the 54 patients tested before treatment demonstrated ability to achieve FR, with FR usually associated with higher ROM than in the non-FR patients. After treatment, 94% of those who completed the program achieved FR, including all those who achieved FR before treatment. Flexion–relaxation was associated with major improvement in ROM and pain disability self-report. Conclusions. Flexion–relaxation measures a point at which true lumbar flexion ROM approaches its maximum in asymptomatic subjects. This also is the point at which lumbar extensor muscle contraction relaxes, allowing the lumbar spine to hang on its posterior ligaments. The gluteal and hamstring muscles then lower the flexed trunk even further by allowing the pelvis to rotate around the hips. This phenomenon was subsequently found in Part 2 to offer a potentially promising method for individualizing rehabilitation treatment, decreasing unnecessary utilization, identifying potential postrehabilitation treatment failures, and assessing permanent impairment rating validity. Moreover, this is the first study to demonstrate systematically that an absence of FR in patients with chronic low back pain can be corrected with treatment.

Ability of the central sensitization inventory to identify central sensitivity syndromes in an outpatient chronic pain sample

Objectives:The aim of this study was to determine the ability of the central sensitization inventory (CSI), a new screening instrument, to assist clinicians in identifying patients with central sensitivity syndromes (CSSs). Methods:Patients from a psychiatric medical practice (N=161), which specialized in the assessment and treatment of complex pain and psychophysiological disorders, were assessed for the presence of a CSS. CSI scores, using a previously determined cutoff of “40” of “100,” were compared between the CSS patient group (n=99) and the non-CSS patient group (n=62). Information on false positives, false negatives, true positives, and true negatives were analyzed, and sensitivity and specificity analyses were conducted. In addition, CSS-relevant variables such as depression, abuse, and substance abuse were examined. Results:A large percentage of CSS patients had comorbid major depressive disorder (80%) and abuse history (43%), which was higher than rates for the patients without a CSS (55% and 24%, respectively). The CSI correctly identified 82.8% (n=82) of CSS patients as having a CSS (ie, sensitivity) and 54.8% (n=28) of non-CSS patients as not having a CSS (ie, specificity). False-positive patients (not diagnosed with a CSS, but scoring >40 on the CSI) reported more severe pain, interference in daily functioning, and abuse history, compared with the non-CSS patients who scored below 40 (ie, true negatives). Conclusions:The CSI is a useful and valid instrument for screening patients for the possibility of a CSS, although the chances of false positives are relatively high when evaluating patients with complex pain and psychophysiological disorders.

Flexion-relaxation and clinical features associated with chronic low back pain: A comparison of different methods of quantifying flexion-relaxation.

ObjectivesThe purpose of this study was to simultaneously assess 5 surface electromyography (SEMG) ratios commonly used to quantify the flexion relaxation phenomenon in chronic low back pain patients relative to clinical and musculoskeletal abnormalities. MethodsSeventy-six persons with low back pain (LBP) were assessed through SEMG in standing, flexion, maximum voluntary flexion, and extension. Additionally, participants were assessed for clinical status (pain intensity, perceived disability, and pain-related fear) and musculoskeletal abnormalities (supine straight leg raise, Faber test, and lumbar restrictions). ResultsFlexion-relaxation assessed as the ratio of maximum SEMG during flexion to average SEMG during maximum voluntary flexion, and maximum SEMG during extension to average SEMG during maximum voluntary flexion, demonstrated that highest associations with clinical and musculoskeletal status. Ratio of maximum SEMG during flexion to average SEMG during maximum voluntary flexion was significantly associated with 2 measures of perceived disability (both rs=−0.31, P<0.01), pain-related fear (r=−0.45, P<0.001), as well as range of motion during flexion (r=0.51, P<0.001), and elicitation of pain during straight leg raise (r=0.30, P<0.05). Ratio of maximum SEMG during extension to average SEMG during maximum voluntary flexion was also significantly associated with these same measures, at a slightly higher magnitude, in addition to a measure of clinical pain (r=−0.29, P<0.05). DiscussionsThese data suggest that measures of flexion-relaxation that contrast SEMG during flexion or extension to MVF are more highly associated with clinical status compared with measures that contrast SEMG during flexion and extension, SEMG whereas standing to MVF, or SEMG during MVF alone.

The quantified lumbar flexion-relaxation phenomenon is a useful measurement of improvement in a functional restoration program.

Study Design. A prospective cohort study evaluating the quantitative lumbar flexion-relaxation phenomenon (QLFRP), measured with surface electromyographic (SEMG) signals from the erector spinae during trunk flexion pre- and postrehabilitation, in patients with chronic disabling occupational lumbar disorders (CDOLD). Objectives. To assess the responsiveness of the QLFRP in documenting change in functional performance during a functional restoration program for CDOLD patients. Summary of Background Data. A recent theoretical construct suggests that QLFRP is responsive to change in lumbar range of motion (ROM) during rehabilitation, with high sensitivity and specificity for abnormal QLFRP predicting ROM. Methods. A cohort of normal subjects was tested for QLFRP correlated to inclinometric lumbar ROM measures. The cutoff score was applied to a group of CDOLD patients entering a functional restoration program (N = 135), and to program completers (N = 104). Pain and functional self-report scores were compared with SEMG and ROM measures. Results. The CDOLD group averaged 23.7 months off work. Surgical treatment was provided prerehabilitation to 51% of patients, with 29% receiving lumbar fusions. From pre- to post-treatment, achievement of QLFRP rose from 31% to 74% of patients, while normal ROM rose from 8% to 63% of patients. Compared to the 16% of patients still demonstrating both abnormal QLFRP and ROM, the other groups showed significantly greater improvement in self-reported pain and function, with the best improvements occurring in patients showing normal ROM and QLFRP. The QLFRP showed high sensitivity, but only modest predictive validity and specificity for predicting ROM postrehabilitation. Improvement in sensitivity and predictive validity occur when surgical cases were excluded from the analysis. Conclusion. A majority of patients in an interdisciplinary functional restoration program failed to demonstrate either the QLFRP or normal ROM on admission to the program. A majority of program completers, however, achieved both normal ROM and QLFRP and another 30% demonstrated either normal QLFRP or normal ROM. Both QLFRP and ROM measures were responsive to relevant self-report scales.

Correcting Abnormal Flexion-Relaxation in Chronic Lumbar Pain: Responsiveness to a New Biofeedback Training Protocol

ObjectivesLumbar flexion-relaxation is a well-known phenomenon that can reliably be seen in normal participants, but not in most chronic low back pain (CLBP) participants. No earlier studies have investigated any specific clinical intervention designed to correct abnormal flexion-relaxation. The objective of this study was to evaluate the contribution of a surface EMG-assisted stretching (SEMGAS) biofeedback training protocol, within a functional restoration treatment program, on flexion range of motion (ROM) and erector spinae surface EMG (SEMG) during maximum voluntary flexion (MVF). MethodsLumbar flexion ROM and MVF SEMG were assessed in 2 groups of CLBP patients at the beginning and end of rehabilitation. One group participated in functional restoration only, whereas the other group participated in functional restoration plus SEMGAS biofeedback training. Both treatment groups were compared with a separate control group of normal, pain-free participants. ResultsPretreatment ROM and MVF SEMG measures were similar in both treatment groups, but were very different than the control group. At posttreatment, the functional restoration only group remained statistically different than the control group on MVF SEMG and some ROM measures, but the SEMGAS group was statistically equivalent to the control participants on all posttreatment measures, including the ability to show flexion-relaxation. DiscussionInterdisciplinary functional restoration rehabilitation of CLBP participants is effective for increasing ROM and other functional measures, but the addition of a SEMGAS biofeedback training protocol can result in normalization of the flexion-relaxation phenomenon, so that these participants are comparable with a pain-free control group.

Chronic Widespread Pain in Patients With Occupational Spinal Disorders : Prevalence, Psychiatric Comorbidity, and Association With Outcomes

Study Design. A prospective study assessing chronic widespread pain (CWP) and psychiatric comorbidities in patients with chronic disabling occupational spinal disorders (CDOSDs). Objective. To assess the prevalence of CWP, demographic characteristics, and associated psychiatric comorbidity among CDOSD patients, as well as determine if CWP is a risk factor for less successful one-year postrehabilitation socioeconomic outcomes. Summary of Background Data. CWP is an essential criterion for diagnosing fibromyalgia. CWP is estimated to affect between 4.1% to 13.5% of the general population and it is associated with higher rates of psychiatric disorders and growing rates of disability. The prevalence of CWP, or its associations as a comorbidity, in patients with CDOSDs are unknown. Methods. The socioeconomic outcomes, demographic characteristics, and psychiatric comorbidity of CDOSD patients with CWP were compared to non-CWP patients within a cohort of consecutive CDOSD patients (n = 2730), treated in an interdisciplinary functional restoration program. CWP was determined according to American College of Rheumatology criteria. Psychiatric comorbidity was assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders—fourth Edition at the beginning of the rehabilitation program. Results. In the CDOSD cohort, 32% of the patients (N = 878) met American College of Rheumatology criteria for CWP, relative to 4.1% to 13.5% within the general population. CWP patients (82%) were much more likely than non-CWP patients (16%) to have multisite pain complaints, leading to the finding that CDOSD patients with multisite pain showed a CWP prevalence of 70%. CWP patients were 1.5 times more likely to be female, more likely to have multiple compensable injuries, and had slightly elevated rates of pre- and postinjury Axis I psychopathology. Nevertheless, CWP was not associated with less successful 1-year socioeconomic outcomes. Conclusion. A surprisingly high frequency of CDOSD patients participating in interdisciplinary rehabilitation met criteria for CWP, though the diagnosis was generally unknown to the patient. In this large workers’ compensation cohort, CWP was not associated with longer periods of disability, more prerehabilitation surgery or higher pain self-report. With appropriate rehabilitation, CWP patients can have equally successful work return and health utilization outcomes compared to non-CWP patients, despite having significantly higher rates of certain psychiatric disorders.

Establishing Clinically Relevant Severity Levels for the Central Sensitization Inventory.

The aim of this study was to create and validate severity levels for the central sensitization inventory (CSI), a valid and reliable patient‐reported outcome instrument designed to identify patients whose presenting symptoms may be related to a central sensitivity syndrome (CSS; eg, fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome), with a proposed common etiology of central sensitization (CS).

A clinical guide to surface-EMG-assisted stretching as an adjunct to chronic musculoskeletal pain rehabilitation.

Therapeutic stretching is a vital component of chronic musculoskeletal pain rehabilitation for increasing range of motion and counteracting the effects of physical deconditioning. Surface EMG biofeedback is currently being used to facilitate movement and to maximize effective stretching with patients in an interdisciplinary chronic pain rehabilitation program for disabled workers. A clinical protocol with case examples is presented.

Insomnia in a chronic musculoskeletal pain with disability population is independent of pain and depression.

BACKGROUND CONTEXT Insomnia is frequently experienced by patients suffering from chronic musculoskeletal disorders but is often seen as simply a symptom of pain or depression and not as an independent disorder. Compared with those who experience only chronic pain, patients with both chronic pain and insomnia report higher pain intensity, more depressive symptoms, and greater distress. However, insomnia has not yet been systematically studied in a chronic musculoskeletal pain with disability population. PURPOSES This study assessed the prevalence and severity of patient-reported insomnia, as well as the relationship among insomnia, pain intensity, and depressive symptoms, in a chronic musculoskeletal pain with disability population. STUDY DESIGN/SETTING This was a retrospective study of prospectively captured data. PATIENT SAMPLE A consecutive cohort of 326 chronic musculoskeletal pain with disability patients (85% with spinal injuries) entered a functional restoration treatment program. All patients signed a consent form to participate in this protocol. OUTCOME MEASURES Insomnia was assessed with the Insomnia Severity Index, a validated patient-report measure of insomnia symptoms. Four patient groups were formed: no clinically significant insomnia (score, 0-7); subthreshold insomnia (score, 8-14); moderate clinical insomnia (score, 15-21); and severe clinical insomnia (score, 22-28). Three patterns of sleep disturbance were also evaluated: early, middle, and late insomnia. Additional validated psychosocial patient-reported data were collected, including the Pain Visual Analog Scale, the Beck Depression Inventory, the Oswestry Disability Index, and the Pain Disability Questionnaire. METHODS Patients completed a standard psychosocial assessment battery on admission to the functional restoration program. The program included a quantitatively directed exercise process in conjunction with a multimodal disability management approach. The four insomnia groups were compared on demographic and psychosocial variables. The shared variances among insomnia, depression, and pain were determined by partial correlational analyses. RESULTS The presence of no clinically significant insomnia, subthreshold insomnia, moderate clinical insomnia, and severe clinical insomnia was found in 5.5%, 21.2%, 39.6%, and 33.7% of the cohort, respectively. More than 70% of patients reported moderate to severe insomnia symptoms, which is a considerably higher prevalence than that found in most patient cohorts studied previously. A stepwise pattern was found, in which severe clinical insomnia patients reported the highest pain, the most severe depressive symptoms, and the greatest disability. The severe clinical insomnia patients also reported a higher number of sleep disturbance types (early, middle, and late insomnia) than the other three groups. In fact, 62.9% of them reported all three disturbance types. Although correlations were found between insomnia and depressive symptoms and between insomnia and pain, the shared variances were small (12.9% and 3.6%, respectively), indicating that depression and pain are separate constructs from insomnia. CONCLUSION This research indicates that insomnia is a significant and pervasive problem in a chronic musculoskeletal pain with disability population. Most importantly, although insomnia has traditionally been assumed to be simply a symptom of pain or depression, the findings of the present study reveal that it is a construct relatively independent from both pain and depression. Specific insomnia assessment and treatment is therefore recommended for this chronic musculoskeletal pain with disability population.