European journal of pain : EJP
-
Diffuse noxious inhibitory controls (DNIC) as measured in rat and conditioned pain modulation (CPM), the supposed psychophysical paradigm of DNIC measured in humans, are unique manifestations of an endogenous descending modulatory pathway that is activated by the application of a noxious conditioning stimulus. The predictive value of the human CPM processing is crucial when deliberating the translational worth of the two phenomena. ⋯ This study provides novel evidence that a comparable noxious cuff pressure paradigm activates a unique form of endogenous inhibitory control in healthy rat and man. This has important implications for the forward translation of bench and experimental pain research findings to the clinical domain. If translatable mechanisms underlying dysfunctional endogenous inhibitory descending pathway expression (previously evidenced in painful states in rat and man) were revealed using cuff pressure algometry, the identification of new analgesic targets could be expedited.
-
This study aimed to establish the somatosensory profile of patients with lumbar radiculopathy at pre-and post-microdiscectomy and to explore any association between pre-surgical quantitative sensory test (QST) parameters and post-surgical clinical outcomes. ⋯ This study documented quantitative sensory testing (QST) profiles in patients with lumbar radiculopathy in their main pain area (MPA) and dermatome pre- and post-microdiscectomy and explored associations between QST parameters and clinical outcome. Lumbar radiculopathy was associated with loss of function in modalities mediated by large and small sensory fibres. Microdiscectomy resulted in significant improvements in loss of function and clinical outcomes in 85% of our cohort. Pre-surgical mechanical detection thresholds in the MPA may be predictive of clinical outcome.
-
Recent evidence from event-related potentials (ERPs) has identified N2 posterior contralateral (pc) amplitudes as a neural marker of early attention allocation. The N2pc has been used to evaluate attention biases (ABs) in samples with anxiety-based problems, but its utility has yet to be considered among persons with chronic pain, another group theorized to display ABs that perpetuate their difficulties. To address this gap, we assessed N2pc responses of adults with chronic pain (N = 70) and pain-free controls (N = 70) during a dot-probe task comprising painful-neutral and happy-neutral facial expression image pairs. ⋯ Overall N2pc results reflected general biases in early allocation of attention towards affectively valenced expressions rather than pain-specific ABs among chronic pain cohorts. SIGNIFICANCE: Although numerous researchers have examined pain-related attention biases, these data are based exclusively upon behavioural measures of attention such as reaction times and eye movements. Drawing from relevant event-related potentials research, this study is the first to evaluate and identify differences in orienting of attention between adults with chronic pain and pain-free controls based on N2 posterior contralateral (pc) amplitudes which provide a neural index of early attention allocation.