Pain
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Temporomandibular disorders (TMD) include a group of musculoskeletal disorders that may involve increased responsiveness of nociceptive neurons in the central nervous system (ie, central sensitization). To test this hypothesis further, this study examined whether, as compared with healthy subjects, patients with chronic TMD have a greater propensity to develop secondary mechanical hyperalgesia-a phenomenon that can be confidently attributed to central sensitization. In this case-control study, we assessed the area of secondary mechanical hyperalgesia induced experimentally by delivering high-frequency electrical stimulation (HFS) to the volar forearm skin in 20 participants with chronic TMD and 20 matched healthy controls. ⋯ Regarding secondary outcomes, there was no group difference in the intensity of secondary mechanical hyperalgesia, but allodynia to cotton after HFS was more frequent in the chronic TMD group. To the best of our knowledge, this is the first study to show that individuals with chronic TMD have an increased propensity to develop secondary hyperalgesia in a site innervated extratrigeminally. Our results contribute to a better understanding of the pathophysiology of chronic TMD.
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Complex regional pain syndrome (CRPS) is characterized by inflammation and a failure of multimodal signal integration in the central nervous system (CNS). Central nervous system reorganization might account for sensory deficits, pain, and motor symptoms in CRPS, but it is not clear how motor control is affected by CNS mechanisms. The present study characterized the motor performance and related cortical activity of 16 CRPS patients and 16 control participants during the planning of visually guided unimanual grips, in patients with either the unaffected left or the affected right hand, and investigated resting-state sensorimotor coupling in MRI. ⋯ Fear of movement or individual pain scores contributed only marginally to the observed effects. The study suggests that changes in planning-related sensorimotor CNS regions may explain difficulties with force exertion and motor control in CRPS. Perspective : Functional changes in motor planning-related brain regions might indicate that feedback-enhanced functional motor training may be effective for CRPS rehabilitation.
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Pain is a common symptom in patients referred to polyneuropathy assessment. Diagnostic evaluation and choice of treatment may depend on whether the pain is likely to be neuropathic or not. This study aimed to investigate the diagnostic accuracy of 3 tools commonly used to differentiate between neuropathic and nonneuropathic pain. ⋯ Only DN4 demonstrated high sensitivity (0.87), whereas all 3 tools had low specificity (≤0.65). Importantly, the tools' predictive ability was unsatisfactory; The probability of getting a correct test result was 3 quarters at best, and at worst, no better than two fifths. Consequently, we show that neither DN4, painDETECT, nor S-LANSS can be confidently used to assess neuropathic pain in a neurological outpatient population with symptoms of polyneuropathy.