Pain
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Cut points that classify pain intensity into mild, moderate, and severe levels are widely used in pain research and clinical practice. At present, there are no agreed-upon cut points for the visual analog scale (VAS) in pediatric samples. We applied a method based on Serlin and colleagues' procedure (Serlin RC, Mendoza TR, Nakamura Y, Edwards KR, Cleeland CS. ⋯ We found a set of cut points that can be used both parental ratings of their children's pain and self-reports for adolescents. Adopting these cut points greatly enhances the comparability of trials. We call for more systematic assessment of diagnostic procedures in pain research.
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Patients with low back pain (LBP; N = 102), fibromyalgia (FM; N = 100), and headache (HA; N = 100) were asked to describe their pain in their own words, and the words and phrases they used were then classified into 7 global domains (eg, Pain Quality, Pain Magnitude) and as many specific subdomains as needed to capture all of the ideas expressed (eg, under Pain Quality, subdomains such as sharp, achy, and throbbing). Fifteen pain quality subdomains were identified as most common. Nine of these demonstrated significant between-group differences in frequency. ⋯ The findings are generally consistent with a study that used similar procedures in other patient samples to identify the most common words patients use to describe pain, supporting their generalizability. The findings also support the use of pain quality measures for discriminating between chronic pain conditions. Finally, the findings have important implications for evaluating and modifying pain quality measures as needed.
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Patients with complex regional pain syndrome (CRPS) frequently show prominent sensory abnormalities in their affected limb, which may extend proximally and even to unaffected body regions. This study examines whether sensory dysfunction is observed in unaffected body parts of CRPS patients, and investigates whether the extent of dysfunction is similar for the various sensory modalities. Quantitative sensory testing was performed in the unaffected extremities and cheeks of 48 patients with CRPS of the arm (31 with dystonia), and the results were compared with values obtained among healthy controls. ⋯ Except for a lower vibration threshold in the contralateral leg of CRPS patients with dystonia, no differences in sensory modalities were found between CRPS patients with and without dystonia. These results point to a general disturbance in central pain processing in patients with CRPS, which may be attributed to impaired endogenous pain control. Since pressure pain is the most deviant sensory abnormality in both unaffected and affected body regions of CRPS patients, this test may serve as an important outcome parameter in future studies and may be used as a tool to monitor the course of the disease.
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Observational Study
Longitudinal Relationships between Anxiety, Depression, and Pain: Results from a Two Year Cohort Study of Lower Extremity Trauma Patients.
Previous studies have shown that pain, depression, and anxiety are common after trauma. A longitudinal relationship between depression, anxiety, and chronic pain has been hypothesized. Severe lower extremity trauma patients (n = 545) were followed at 3, 6, 12, and 24 months after injury using a visual analog "present pain intensity" scale and the depression and anxiety scales of the Brief Symptom Inventory. ⋯ The results suggest that in the early phase after trauma, pain predicts anxiety and depression, but the magnitude of these relationships are smaller than the longitudinal relationship from anxiety to pain over this period. In the late (or chronic) phase after injury, the longitudinal relationship from anxiety on pain nearly doubles and is the only significant relationship. Despite missing data and a single item measure of pain intensity, these results provide evidence that negative mood, specifically anxiety, has an important role in the persistence of acute pain.
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The Neuropathic Pain Special Interest Group (NeuPSIG) of the International Association for the Study of Pain has proposed a grading system for the presence of neuropathic pain (NeP) using the following categories: no NeP, possible, probable, or definite NeP. To further evaluate this system, we investigated patients with neck/upper limb pain with a suspected nerve lesion, to explore: (i) the clinical application of this grading system; (ii) the suitability of 2 NeP questionnaires (Leeds Assessment of Neuropathic Symptoms and Signs pain scale [LANSS] and the painDETECT questionnaire [PD-Q]) in identifying NeP in this patient cohort; and (iii) the level of agreement in identifying NeP between the NeuPSIG classification system and 2 NeP questionnaires. Patients (n = 152; age 52 ± 12 years; 53% male) completed the PD-Q and LANSS questionnaire and underwent a comprehensive clinical examination. ⋯ Both questionnaires failed to identify a large number of patients with clinically classified definite NeP (LANSS sensitivity 22%, specificity 88%; PD-Q sensitivity 64%, specificity 62%). These lowered sensitivity scores contrast with those from the original PD-Q and LANSS validation studies and may reflect differences in the clinical characteristics of the study populations. The diagnostic accuracy of LANSS and PD-Q for the identification of NeP in patients with neck/upper limb pain appears limited.