European journal of pain : EJP
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Randomized Controlled Trial
Sleep restriction does not potentiate nocebo-induced changes in pain and cortical potentials.
The increased pain sensitivity following reduced sleep may be related to changes in cortical processing of nociceptive stimuli. Expectations shape pain perception and can inhibit (placebo) or enhance (nocebo) pain. Sleep restriction appears to enhance placebo responses; however, whether sleep restriction also affects nocebo responses remains unknown. The aim of the present study was to determine whether sleep restriction facilitates nocebo-induced changes in pain and pain-evoked cortical potentials. ⋯ The present work addresses whether sleep restriction, known to increase the sensitivity of the pain system, facilitates nocebo-induced hyperalgesia. Our findings suggest that this is not the case, indicating that the increased sensitivity of the pain system following nocebo and sleep restriction are mediated by different cortical mechanisms.
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Sinusoidal current stimuli preferentially activate C-nociceptors. Sodium channel isoforms NaV1.7 and NaV1.8 have been implicated in this. Sympathetic efferent neurons lack NaV1.8 and were explored upon sinusoidal activation. ⋯ C-nociceptors in hairy skin are activated by 4 Hz sinusoidal current stimulation at lower intensities than myelinated fibres. Sympathetic efferent neurons-albeit also unmyelinated-are less responsive to sinusoidal activation than nociceptors within the same skin area. Cutaneous sympathetic efferent neurons apparently are less apt than nociceptors to convert slow depolarization into action potentials.
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Fatigue is commonly reported by people with chronic pain. The purpose of the current study was to examine Acceptance and Commitment Therapy (ACT), based on the Psychological Flexibility (PF) model, for fatigue in chronic pain. ⋯ This study investigates the association between fatigue interference and psychological flexibility processes in chronic pain, and the first one investigating fatigue interference as a predictor of functioning in chronic pain following Acceptance and Commitment Therapy (ACT)-based treatment. Findings of the study provide preliminary evidence for the association between ACT and fatigue in people with chronic pain and support the potential benefit of ACT for people with comorbid chronic pain and fatigue.