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Central post-stroke pain affects up to 12% of stroke survivors and is notoriously refractory to treatment. However, stroke patients often suffer from other types of pain of non-neuropathic nature (musculoskeletal, inflammatory, complex regional) and no head-to-head comparison of their respective clinical and somatosensory profiles has been performed so far. We compared 39 patients with definite central neuropathic post-stroke pain with two matched control groups: 32 patients with exclusively non-neuropathic pain developed after stroke and 31 stroke patients not complaining of pain. Patients underwent deep phenotyping via a comprehensive assessment including clinical exam, questionnaires and quantitative sensory testing to dissect central post-stroke pain from chronic pain in general and stroke. While central post-stroke pain was mostly located in the face and limbs, non-neuropathic pain was predominantly axial and located in neck, shoulders and knees (P < 0.05). Neuropathic Pain Symptom Inventory clusters burning (82.1%, n = 32, P < 0.001), tingling (66.7%, n = 26, P < 0.001) and evoked by cold (64.1%, n = 25, P < 0.001) occurred more frequently in central post-stroke pain. Hyperpathia, thermal and mechanical allodynia also occurred more commonly in this group (P < 0.001), which also presented higher levels of deafferentation (P < 0.012) with more asymmetric cold and warm detection thresholds compared with controls. In particular, cold hypoesthesia (considered when the threshold of the affected side was <41% of the contralateral threshold) odds ratio (OR) was 12 (95% CI: 3.8-41.6) for neuropathic pain. Additionally, cold detection threshold/warm detection threshold ratio correlated with the presence of neuropathic pain (ρ = -0.4, P < 0.001). Correlations were found between specific neuropathic pain symptom clusters and quantitative sensory testing: paroxysmal pain with cold (ρ = -0.4; P = 0.008) and heat pain thresholds (ρ = 0.5; P = 0.003), burning pain with mechanical detection (ρ = -0.4; P = 0.015) and mechanical pain thresholds (ρ = -0.4, P < 0.013), evoked pain with mechanical pain threshold (ρ = -0.3; P = 0.047). Logistic regression showed that the combination of cold hypoesthesia on quantitative sensory testing, the Neuropathic Pain Symptom Inventory, and the allodynia intensity on bedside examination explained 77% of the occurrence of neuropathic pain. These findings provide insights into the clinical-psychophysics relationships in central post-stroke pain and may assist more precise distinction of neuropathic from non-neuropathic post-stroke pain in clinical practice and in future trials.

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REVIEW: The pain that commonly occurs after brachial plexus avulsion poses an additional burden on the quality of life of patients already impaired by motor, sensory and autonomic deficits. Evidence-based treatments for the pain associated with brachial plexus avulsion are scarce, thus frequently leaving the condition refractory to treatment with the standard methods used to manage neuropathic pain. Unfortunately, little is known about the pathophysiology of brachial plexus avulsion. Available evidence indicates that besides primary nerve root injury, central lesions related to the abrupt disconnection of nerve roots from the spinal cord may play an important role in the genesis of neuropathic pain in these patients and may explain in part its refractoriness to treatment. CONCLUSIONS: The understanding of both central and peripheral mechanisms that contribute to the development of pain is of major importance in order to propose more effective treatments for brachial plexus avulsion-related pain. This review focuses on the current understanding about the occurrence of neuropathic pain in these patients and the role played by peripheral and central mechanisms that provides insights into its treatment. Pain after brachial plexus avulsion involves both peripheral and central components; thereby it is characterized as a mixed (central and peripheral) neuropathic pain syndrome.

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Estimulação magnética transcraniana (EMT) é uma técnica conhecida desde o começo dos anos 90 e que atualmentetem ganhado destaque devido a sua segurança e possível aplicabilidade para tratar diversas patologias neuropsiquiátricas refratárias. A fim de clarificar os possíveis usos da EMT e suas variações no campo da clínica como forma de tratamento, procedemos à revisão da literatura selecionando os artigos nas áreas em que a técnica de EMT já tem sido largamente utilizada,a saber: AVC, Dor, Doença de Parkinson e Depressão. Essas doenças possuem elevada morbidade, possuindo grandesimplicações na qualidade de vida devido ao elevado grau de incapacidade associado e ao fato de ainda carecerem de métodos terapêuticos totalmente eficientes. Nesse contexto, a EMT emerge como ferramenta promissora, apresentando bons resultados, os quais fornecem margem para aplicações diretas na prática clínica. É necessário, todavia, o desenvolvimento de mais estudos randomizados, para se padronizar e aperfeiçoar as abordagensdessa técnica no tratamento de tais patologias...

Transcranial Magnetic Stimulation (TMS) is a technique that emerged in the 90s and has currently become recognized for its safety and potential applicability in the treatment of neuropsychiatry diseases. To clarify the possible uses of TMS and its variations in the clinical scope as a treatment, weproceeded a literature review selecting articles in the areas where the technique of TMS has already been widely used: Stroke, Pain, Parkinson’s Disease and Depression. These diseases have high morbidity, with large implications for the quality of life due to the high degree of disability and the fact that we still lack of fully efficient therapeutic methods. In this context, EMT emerges as a promising tool with amazing results, which provide scope for direct applications in clinical practice. However, the developmentof more randomized studies is necessary, in order to standardizeand improve the approaches of this technique in the treatment of such pathologies...

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