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Worldwide, the incidence of wrist fracture is increasing. There are currently no externally validated prognostic models to inform early decision making for these patients.To develop and validate a prognostic model from a comprehensive range of candidate prognostic factors that can identify patients who are at risk of developing persistent pain following wrist or hand fracture.We developed and validated a prognostic model using secondary data derived from a prospective cohort study (n = 715), with recruitment sites in 3 metropolitan hospitals in Sydney, Australia. The primary outcome was persistent pain 4 months following the injury. The current study used a backward stepwise regression analysis to develop the model in 2 hospitals (n = 408) and externally validate it in a third hospital (n = 307). To determine the accuracy of the model, we assessed calibration and discrimination in accordance with the PROGnosis RESearch Strategy framework.Complete data were available for 95% of the cohort. Of 14 candidate variables, the final model contained 2 prognostic factors: patient age and pain intensity reported at initial presentation. The area under the receiver operating characteristic curve was 0.63 (95% confidence interval: 0.56, 0.69) in the development sample and 0.61 (95% confidence interval: 0.51, 0.70) in the validation sample. The model systematically overestimated risk (intercept, -1.13; slope, 0.73).We developed and externally validated a prognostic model to predict persistent pain 4 months after a wrist or hand fracture. Future studies are needed to assess whether the accuracy of this model can be improved by updating and validating it in local settings.Prognosis, level 1b. J Orthop Sports Phys Ther 2019;49(1):28-35. Epub 12 Sep 2018. doi:10.2519/jospt.2019.8342.

It has long been known that the somatosensory cortex gates sensory inputs from the contralateral side of the body. Here, we examined the contribution of the ipsilateral somatosensory cortex (iS1) to sensory gating during index finger voluntary activity. The amplitude of the P25/N33, but not other somatosensory evoked potential (SSEP) components, was reduced during voluntary activity compared with rest. Interhemispheric inhibition between S1s and intracortical inhibition in the S1 modulated the amplitude of the P25/N33. Note that changes in interhemispheric inhibition between S1s correlated with changes in cortical circuits in the ipsilateral motor cortex. Our findings suggest that cortical circuits, probably from somatosensory and motor cortex, contribute to sensory gating in the iS1 during voluntary activity in humans.An important principle in the organization of the somatosensory cortex is that it processes afferent information from the contralateral side of the body. The role of the ipsilateral somatosensory cortex (iS1) in sensory gating in humans remains largely unknown. Using electroencephalographic (EEG) recordings over the iS1 and electrical stimulation of the ulnar nerve at the wrist, we examined somatosensory evoked potentials (SSEPs; P14/N20, N20/P25 and P25/N33 components) and paired-pulse SSEPs between S1s (interhemispheric inhibition) and within (intracortical inhibition) the iS1 at rest and during tonic index finger voluntary activity. We found that the amplitude of the P25/N33, but not other SSEP components, was reduced during voluntary activity compared with rest. Interhemispheric inhibition increased the amplitude of the P25/N33 and intracortical inhibition reduced the amplitude of the P25/N33, suggesting a cortical origin for this effect. The P25/N33 receives inputs from the motor cortex, so we also examined the contribution of distinct sets of cortical interneurons by testing the effect of ulnar nerve stimulation on motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the ipsilateral motor cortex with the coil in the posterior-anterior (PA) and anterior-posterior (AP) orientation. Afferent input attenuated PA, but not AP, MEPs during voluntary activity compared with rest. Notably, changes in interhemispheric inhibition correlated with changes in PA MEPs. Our novel findings suggest that interhemispheric projections between S1s and intracortical circuits, probably from somatosensory and motor cortex, contribute to sensory gating in the iS1 during voluntary activity in humans.

That complex regional pain syndrome (CRPS) is associated with functional reorganization in the primary somatosensory cortex (S1) is widely accepted and seldom questioned. Despite more than a decade of research, there has been no systematic review of the CRPS literature concerning the changes in S1 function, and therefore the extent of these changes is unclear. Here we conduct a systematic review and meta-analysis to quantify the spatial and temporal aspects of S1 function in CRPS. A comprehensive search strategy identified functional neuroimaging studies of S1 in CRPS. We adhered to a rigorous systematic review protocol when extracting data and appraising risk of bias. Outcomes were grouped into spatial representation; activation levels, including disinhibition; peak latency of activation; and glucose metabolism. Meta-analysis was conducted where possible. Fifteen studies were included, all investigating upper-extremity CRPS. In patients with CRPS, the S1 spatial representation of the affected hand is smaller than that of the unaffected hand and that of non-CRPS controls; however, this evidence comes from only a few studies. There is no difference in activation, disinhibition, or latency of peripherally evoked S1 responses in CRPS. The risk of bias was high across studies, mainly from unclear sampling methods and unblinded analysis of outcomes. Perspective: The evidence for a difference in function of the primary somatosensory cortex in CRPS compared with controls is clouded by high risk of bias and conflicting results, but reduced representation size seems consistent. Refereed/Peer-reviewed

Objective: Chronic pain is a common problem that is associated with mood disorders such as depression. The Depression, Anxiety, and Stress Scales (DASS-21) questionnaire is commonly used to help measure disordered mood. In this study, we used Rasch analysis to analyze the clinimetric properties of the DASS-21 in a chronic low back pain sample. Study Design and Setting: A Rasch analysis was conducted on data collected as a part of a randomized hospital-based placebo controlled trial. DASS-21 questionnaires were completed by the 154 enrolled participants. Results: The DASS-21 subscales fit the Rasch model. No differential item functioning was detected for age, gender, pain severity, or disability. Reliability for individual use was supported for the depression subscale (Person Separation Index [PSI]50.86) but group use only for the anxiety (PSI50.74) and stress (PSI50.82) subscales. A DASS-21 aggregate score of ‘‘negative affect’’ lacked fit to the Rasch model (c25191.48, P!0.001). Conclusion: This is the first study that used Rasch analysis to demonstrate that the DASS-21 subscales demonstrate adequate measurement properties for research involving groups with chronic pain. Only the DASS-21 depression subscale demonstrated adequate reliability for use with individuals with chronic pain. The use of a single DASS-21 aggregate score as a measure of ‘‘negative affect’’ was not supported. Refereed/Peer-reviewed

A growing body of literature suggests that alterations in brain structure and function are a feature of chronic back pain. Tactile acuity is considered a clinical signature of primary somatosensory representation and offers a simple measure of cortical reorganisation. Clinical interpretation of test scores from an individual patient is hampered by variance in published normative values and less than ideal inter-rater reliability. These problems might be mitigated in people with unilateral back pain by using the patient as their own control and comparing tactile acuity at the painful site to performance at the corresponding position on the non-painful side. The first step in exploring this approach is to quantify the normal sideto- side difference in healthy populations. We pooled data from three previous studies that measured lumbar tactile acuity bilaterally in healthy controls using similar protocols. We calculated the mean and variance of the absolute error between sides, the standard error of measurement and the reliable change index (RCI). The mean difference between sides was 3.2 mm ( 5.2) when assessed vertically and 1.9 mm ( 3.2) when assessed horizontally. The standard error of measurement was 4.2 mm when assessed vertically and 2.7 mm when assessed horizontally. The RCI suggests that differences of greater than 13 mm when assessed horizontally and 17 mm when assessed vertically equate to 95% confidence that a difference truly exists. Several assumptions related to the application of this approach need to be investigated further. Refereed/Peer-reviewed

Background The Pain Self-Efficacy Questionnaire (PSEQ) is used by physical therapists in clinical practice and in research. However, current understanding of the PSEQ's measurement properties is incomplete, and investigators cannot be confident that it provides unbiased information on patient self-efficacy. Objective The aims of this study were: (1) to investigate the scale properties of the PSEQ using Rasch analysis and (2) to determine whether age, sex, pain intensity, pain duration, and pain-related disability bias function of the PSEQ. Design This was a retrospective study; data were obtained from 3 existing studies. Methods Data were combined from more than 600 patients with low back pain of varying duration. Rasch analysis was used to evaluate targeting, category ordering, unidimensionality, person fit, internal consistency, and item bias. Results There was evidence of adequate category ordering, unidimensionality, and internal consistency of the PSEQ. Importantly, there was no evidence of item bias. Limitations The PSEQ did not adequately target the sample; instead, it targeted people with lower self-efficacy than this population. Item 7 was hardest for participants to endorse, showing excessive positive misfit to the Rasch model. Response strings of misfitting persons revealed older participants and those reporting high levels of disability. Conclusions The individual items of the PSEQ can be validly summed to provide a score of self-efficacy that is robust to age, sex, pain intensity, pain duration, and disability. Although item 7 is the most problematic, it may provide important clinical information and requires further investigation before its exclusion. Although the PSEQ is commonly used with people with low back pain, of whom the sample in this study was representative, the results suggest it targets patients with lower self-efficacy than that observed in the current sample.

In unilateral upper-limb complex regional pain syndrome (CRPS), the temperature of the hands is modulated by where the arms are located relative to the body midline. We hypothesized that this effect depends on the perceived location of the hands, not on their actual location, nor on their anatomical alignment. In 2 separate cross-sectional randomized experiments, 10 (6 female) unilateral CRPS patients wore prism glasses that laterally shifted the visual field by 20. Skin temperature was measured before and after 9-minute periods in which the position of one hand was changed. Placing the affected hand on the healthy side of the body midline increased its temperature (Δ C = +0.47 ± 0.14 C), but not if prism glasses made the hand appear to be on the body midline (Δ C = +0.07 ± 0.06 C). Similarly, when prism glasses made the affected hand appear to be on the healthy side of the body midline, even though it was not, the affected hand warmed up (Δ C = +0.28 ± 0.14 C). When prism glasses made the healthy hand appear to be on the affected side of the body midline, even though it was not, the healthy hand cooled down (Δ C = -0.30 ± 0.15 C). Friedman's analysis of variance and Wilcoxon pairs tests upheld the results (P < 0.01 for all). We conclude that, in CRPS, cortical mechanisms responsible for encoding the perceived location of the limbs in space modulate the temperature of the hands. © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.