European journal of pain : EJP
-
Randomized Controlled Trial
What factors influence the measurement properties of the Roland-Morris disability questionnaire?
Although the Roland disability questionnaire (RDQ) is a commonly used questionnaire for patients with low back pain (LBP), several important issues remain understudied. The purposes of this study were to investigate the impact that several parameters (length of test-retest interval, interpretation of the global perceived effect (GPE) scores, methods to estimate standard error of measurement (SEM), intervention and baseline scores) have on various measurement properties, such as agreement (Limits of Agreement (LOA), SEM(agreement)), responsiveness (area under the ROC curve, sensitivity, specificity) and interpretability (optimal cut-off point, Minimal Detectable Change), of the RDQ. RDQ was administered four times to 212 patients with chronic non-specific LBP (first consultation (T-1), eligibility check (T0), randomization/start of treatment (T1) and end of treatment (T2)). ⋯ Results revealed that agreement parameters decreased with increasing time interval between test-retest. They confirmed the influence of the interpretation of the GPE as well as of the method to calculate the SEM on the magnitude of the Minimal Detectable Change and ROC parameters. Baseline RDQ scores and the way to cluster patients with regard to baseline scores influenced mainly the optimal cut-off point and responsiveness parameters; intervention did not affect the magnitude of the Minimal Detectable Change.
-
Randomized Controlled Trial
Brush-evoked allodynia predicts outcome of spinal cord stimulation in complex regional pain syndrome type 1.
Spinal cord stimulation (SCS) has proven to be an effective however an invasive and relatively expensive treatment of chronic Complex Regional Pain Syndrome type 1(CRPS-1). Furthermore, in one third of CRPS-1 patients, SCS treatment fails to give significant pain relief and 32-38% of treated patients experience complications. The aim of the current study was to develop effective prognostic factors for prediction of successful outcome of SCS. ⋯ Brush-evoked allodynia may be a significant negative prognostic factor of SCS treatment outcome after 1 year in chronic CRPS-1.
-
Chronic pain is often associated with comorbidities such as anxiety and depression, resulting in a low health-related quality of life. The mechanisms underlying this association are not clear, but a disturbance in the pain control systems from the brain stem has been suggested. Thirty neuropathic pain (NP) patients, 28 patients with fibromyalgia (FM), and 26 pain-free age- and gender-matched controls were included and examined with respect to mental distress (self-rated Symptom Checklist-92), depression (doctor-rated Hamilton Depression Scale and self-rated Major Depression Inventory), and anxiety (doctor-rated Hamilton Anxiety Scale and self-rated Anxiety Inventory). ⋯ However, these scores are low compared to other studies on mental distress in chronic pain patients. Only few chronic pain patients meet the diagnostic criteria for depression (NP 3.3%, FM 7.1%), and associations between pain and mental symptoms were only found in the FM group despite similar pain intensities. The findings suggest that different mechanisms are responsible for the development of mood disorders in the two patient groups.
-
Diffusion Tensor Imaging (DTI) is a promising new imaging method allowing in vivo mapping of anatomical connections in the living human brain. We combined DTI with functional magnetic resonance imaging (fMRI) to investigate the anatomical relationships between areas involved in visceral sensations in humans. Non-painful and moderately painful rectal distensions were performed in 11 healthy women (38.4+/-3.1years). fMRI was used to analyse the changes in brain activity during both types of distension. ⋯ DTI revealed direct connections between insula, and the four areas more frequently activated in this study, i.e. ACC, thalamus, S1, S2 and PFC. The combined use of fMRI and DTI in healthy subjects during rectal distension revealed a neural network of visceral sensory perception involving the insula, thalamus, somatosensory cortices, ACC and PFC.
-
Most forms of visceral pain generate intense referred hyperalgesia but the mechanisms of this enhanced visceral hypersensitivity are not known. The on-cells of the rostral ventromedial medulla (RVM) play an important role in descending nociceptive facilitation and can be sensitized to somatic mechanical stimulation following peripheral nerve injury or hindpaw inflammation. Here we have tested the hypothesis that visceral noxious stimulation sensitizes RVM ON-like cells, thus promoting an enhanced descending facilitation that can lead to referred visceral hyperalgesia. ⋯ Moreover, ON-like cells acquired a novel response to CRD and responded to heat stimulation in the innocuous range. OFF-like neurons responded to capsaicin administration with a brief (<5 min) inhibition of activity followed by an enhanced inhibition to noxious stimulation and a novel inhibition to innocuous stimulation (CRD and heat) at early time points (10 min post capsaicin). These results support the hypothesis that noxious visceral stimulation may cause referred hypersensitivity by promoting long-lasting sensitization of RVM ON-like cells.