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ABSTRACT: Persistent pain is a common reason for reduced quality of life after a spinal cord injury (SCI). Biomarkers of neuropathic pain may facilitate translational research and the understanding of underlying mechanisms. Research suggests that pain and affective distress are anatomically and functionally integrated in the anterior cingulate cortex and can modulate sensory and affective aspects of pain. We hypothesized that severe neuropathic pain with a significant psychosocial impact would be associated with metabolite concentrations (obtained by magnetic resonance spectroscopy) in the anterior cingulate cortex, indicating neuronal and/or glial dysfunction. Participants with SCI and severe, high-impact neuropathic pain (SCI-HPI; n=16), SCI and moderate, low-impact neuropathic pain (SCI-LPI; n=24), SCI without neuropathic pain (SCI-noNP; n=14), and able-bodied, pain-free control subjects (A-B; n=22) underwent a 3-T magnetic resonance imaging brain scan. Analyses revealed that the SCI-HPI group had significantly higher levels of myoinositol (Ins) (P<.000), creatine (P=.007), and choline (P=.014), and significantly lower levels of N-acetyl aspartate/Ins (P=.024) and glutamate-glutamine (Glx)/Ins (P=.003) ratios than the SCI-LPI group. The lower Glx/Ins ratio significantly discriminated between SCI-HPI and the A-B (P=.006) and SCI-noNP (P=.026) groups, displayed excellent test-retest reliability, and was significantly related to greater pain severity, interference, and affective distress. This suggests that the combination of lower glutamatergic metabolism and proliferation of glia and glial activation are underlying mechanisms contributing to the maintenance of severe neuropathic pain with significant psychosocial impact in chronic SCI. These findings indicate that the Glx/Ins ratio may be a useful biomarker for severe SCI-related neuropathic pain with significant psychosocial impact.
Pain 11/2012; · 5.78 Impact Factor
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ABSTRACT: Persistent pain is a common consequence of spinal cord injury. A patient-specific assessment that combines both the identification of pain symptoms and psychosocial factors is needed for a tailored treatment approach. The aim of the study was to define pain symptom profiles and to determine their relationship with psychosocial factors in persons with spinal cord injury.
Face-to-face interview and examination.
VA Medical Center and Miami Project to Cure Paralysis, Miami, Florida.
Persons with spinal cord injury (135 men and 21 women) provided detailed descriptions of 330 neuropathic pains.
The American Spinal Injury Impairment Scale, pain history and measures of pain interference, life satisfaction, locus of control, social support and depression.
The exploratory factor analyses and regression analyses revealed three distinct symptom profiles: 1) aching, throbbing pain, aggravated by cold weather and constipation predicted by a combination of chance locus of control and lower levels of life satisfaction; 2) stabbing, penetrating, and constant pain of high intensity predicted by a combination of pain interference, localized pain, powerful others locus of control and depressed mood; and 3) burning, electric, and stinging pain aggravated by touch and muscle spasms predicted by pain interference.
Although these results need to be replicated in other spinal cord injury samples, our findings suggest that pain symptom profiles may be a useful way to further characterize pain in a comprehensive assessment strategy.
Pain Medicine 10/2009; 10(7):1246-59. · 2.35 Impact Factor
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ABSTRACT: Pain is a prevalent consequence of spinal cord injury (SCI) that can persist for years after the injury and can have a significant impact on physical and emotional function and quality of life. There are a variety of types of pain that may develop after a SCI, including those of primarily nociceptive origin and those of primarily neuropathic origin. Recommendations for diagnostic and treatment strategies have been varied in part because of the lack of a universal classification system and in part because of the biopsychosocial nature of pain. The most recent taxonomy for pain after SCI is described herein. Pain-management strategies, including pharmacological, interventional, and psychological treatments, also are described. For neuropathic pain in SCI, anticonvulsant agents and tricyclic antidepressants often are tried, but these treatments have had limited success in many patients, and alternative interventions (eg, massage therapy, acupuncture, meditation) often are just as successful. Treatment of nociceptive pain after SCI often includes nonsteroidal antiinflammatory agents and acetaminophen, but correction of underlying etiologies and behavior adjustments also should be implemented if possible. An overview of self-report pain questionnaires and scales is also presented to provide the clinician and researcher with a set of tools to evaluate the efficacy of pain interventions.
Der Notarzt 09/2009; 1(12):1077-90. · 0.28 Impact Factor
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ABSTRACT: Quantitative sensory testing (QST) has been used to assess neurological function in various chronic pain patient populations. In the present study, we investigated the ability of QST to reliably characterize somatosensory dysfunction in subjects with spinal cord injury (SCI) and neuropathic pain by measuring mechanical, vibration, and thermal detection and pain thresholds. Test-retest reliability was determined based on data collected from 10 subjects with SCI and neuropathic pain who underwent QST on two occasions approximately 3 weeks apart. The intraclass correlation coefficients for mechanical, vibration, warm, and cool detection thresholds were in the "substantial" range, while thresholds for cold pain and hot pain demonstrated "fair" stability in this sample of patients. To determine the validity of QST in persons with SCI-related neuropathic pain, we evaluated the relationship between somatosensory thresholds and severity of neuropathic pain symptoms with multiple linear regression analysis. Thermal pain threshold was the only QST variable significantly related to the severity of neuropathic pain symptoms. The present study provides preliminary evidence that QST is a reliable and valid adjunct measurement strategy for quantifying the neurological dysfunction associated with neuropathic pain in persons with SCI.
The Journal of Rehabilitation Research and Development 02/2009; 46(1):69-83. · 1.78 Impact Factor
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ABSTRACT: After a spinal cord injury (SCI), people commonly experience several types of persistent pain. Unfortunately, individuals who experience unremitting pain despite various treatments have no choice but to adapt to their pain. Although people may possess different styles of pain adaptation, one can hypothesize that the specific types of pain a person experiences are also important. The present study determined the association between pain characteristics and specific adaptational patterns to pain after SCI. Participants (N = 182) were interviewed regarding pain characteristics and the impact of pain on their psychosocial status. Based on the SCI version of the Multidimensional Pain Inventory (MPI-SCI), they were classified as Dysfunctional, with higher pain severity (PS) and life interference (LI); Interpersonally Supported, with moderately high PS, high social support levels, and less LI; or Adaptive Coper, with lower PS and LI levels. A multinomial logistic regression analysis indicated a robust model fit (chi-square = 63.6, p < 0.0005), predicting MPI-SCI subgroup membership based on a combination of pain intensity (p < 0.0005), extent of pain aggravation (p < 0.01), electric quality of pain (p < 0.01), constancy of pain (p < 0.01), and distribution of pain (p < 0.05). The results of the present study support the biopsychosocial model of pain.
The Journal of Rehabilitation Research and Development 01/2009; 46(1):43-56. · 1.78 Impact Factor
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Thomas N Bryce,
Cecilia Norrbrink Budh,
Diana D Cardenas,
Marcel Dijkers, Elizabeth R Felix,
Nanna B Finnerup,
Paul Kennedy,
Thomas Lundeberg,
J Scott Richards,
Diana H Rintala,
Philip Siddall,
Eva Widerstrom-Noga
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ABSTRACT: To examine the reliability, validity, sensitivity, and practicality of various outcome measures for pain after spinal cord injury (SCI), and to provide recommendations for specific measures for use in clinical trials.
Relevant articles were obtained through a search of MEDLINE, EMBASE, CINAHL, and PubMed databases from inception through 2006.
The authors performed literature searches to find articles containing data relevant to the reliability and validity of each pain outcome measure in SCI and selected non-SCI populations.
After reviewing the articles, an investigator extracted information utilizing a standard template. A second investigator reviewed the chosen articles and the extracted pertinent information to confirm the findings of the first investigator.
Taking into consideration both the quantity and quality of the studies analyzed, judgments on reliability and validity of the measures were made by the two investigators. Based upon these judgments, recommendations were formulated for use of specific measures in future clinical trials. In addition, for a subset of measures a voting process by a larger group of SCI experts allowed formulation of recommendations including determining which measures should be incorporated into a minimal dataset of measures for clinical trials and which ones need revision and further validity and reliability testing before use.
A 0-10 Point Numerical Rating Scale (NRS) is recommended as the outcome measure for pain intensity after SCI, while the 7-Point Guy/Farrar Patient Global Impression of Change (PGIC) scale is recommended as the outcome measure for global improvement in pain. The SF-36 single pain interference question and the Multidimensional Pain Inventory (MPI) or Brief Pain Inventory (BPI) pain interference items are recommended as the outcome measures for pain interference after SCI. Brush or cotton wool and at least one high-threshold von Frey filament are recommended to test mechanical allodynia/hyperalgesia while a Peltier-type thermotester is recommended to test thermal allodynia/hyperalgesia. The International Association for the Study of Pain (IASP) or Bryce-Ragnarsson pain taxonomies are recommended for classification of pain after SCI, while the Neuropathic Pain Scale (NPS) is recommended for measuring change in neuropathic pain and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) for quantitating neuropathic and nociceptive pain discrimination.
The journal of spinal cord medicine 02/2007; 30(5):421-40. · 2.11 Impact Factor
