A pain research strategy for Europe: A European survey and position paper of the European Pain Federation EFIC.

Background: Pain is the leading cause of disability and reduced quality of life worldwide. Despite the increasing burden for patients and healthcare systems, pain research remains underfunded and under focused. Having stakeholders identify and prioritize areas that need urgent attention in the field will help focus funding topics, reduce 'research waste', improve the effectiveness of pain research and therapy and promote the uptake of research evidence.

Preoperative susceptibility to developing secondary hyperalgesia is associated with post-thoracotomy pain at 2 months.

Background: Identifying the subset of patients at risk for developing persistent pain after surgery is clinically important as they could benefit from targeted prevention measures. In this prospective study, we investigated if the preoperative assessment of the individual susceptibility to developing experimentally induced secondary hyperalgesia is associated with post-thoracotomy pain at 2 months.

Methods: Forty-one patients scheduled to undergo a posterolateral thoracotomy were recruited before surgery and followed prospectively for 2 months.

How visual experience shapes body representation.

We do not have a veridical representation of our body in our mind. For instance, tactile distances of equal measure along the medial-lateral axis of our limbs are generally perceived as larger than those running along the proximal-distal axis. This anisotropy in tactile distances reflects distortions in body-shape representation, such that the body parts are perceived as wider than they are.

Studying the Effect of Expectations on High-Frequency Electrical Stimulation-Induced Pain and Pinprick Hypersensitivity.

Negative expectations can increase pain, but can they promote the development of central sensitization? This study used an inert treatment and verbal suggestions to induce expectations of increased high-frequency electrical stimulation (HFS)-induced pain and assessed their effects on pain ratings during HFS and HFS-induced pinprick hypersensitivity. Fifty healthy volunteers were randomly allocated to either a control group (N = 25) or a nocebo group (N = 25). Participants in both groups received a patch containing water on the right forearm.

Systematic review and co-ordinate based meta-analysis to summarize the utilization of functional brain imaging in conjunction with human models of peripheral and central sensitization.

Background And Objective: Functional magnetic resonance imaging, in conjunction with models of peripheral and/or central sensitization, has been used to assess analgesic efficacy in healthy humans. This review aims to summarize the use of these techniques to characterize brain mechanisms of hyperalgesia/allodynia and to evaluate the efficacy of analgesics.

Databases And Data Treatment: Searches were performed (PubMed-Medline, Cochrane, Web of Science and Clinicaltrials.

Modulation of the spinal N13 SEP component by high- and low-frequency electrical stimulation. Experimental pain models matter.

Objective: The N13 component of somatosensory evoked potential (N13 SEP) represents the segmental response of cervical dorsal horn neurons. Neurophysiological studies in healthy participants showed that capsaicin-induced central sensitization causes an increase of the N13 SEP amplitude. Consequently, in human research, this spinal component may serve as a valuable readout of central sensitization.

Poor preoperative performance at Clock Drawing Test is associated with postoperative decline in olfaction in older patients: an observational pilot study.

Background: Decline in olfaction may occur after general anesthesia, but the exact incidence and underlying physiopathology remain scarcely investigated. Olfactory dysfunction arises with aging and is known to be linked to cognitive impairment. In this pilot study, we evaluated the incidence of immediate postoperative decline in olfaction and its association with a preoperative cognitive test, performance at Clock Drawing Test (CDT), in a group of older patients.

Intra-operative electroencephalogram frontal alpha-band spectral analysis and postoperative delirium in cardiac surgery: A prospective cohort study.

Background: Postoperative delirium (POD) remains a frequent complication after cardiac surgery, with pre-operative cognitive status being one of the main predisposing factors. However, performing complete pre-operative neuropsychological testing is challenging. The magnitude of frontal electroencephalographic (EEG) α oscillations during general anaesthesia has been related to pre-operative cognition and could constitute a functional marker for brain vulnerability.

Pinprick-induced gamma-band oscillations are not a useful electrophysiological marker of pinprick hypersensitivity in humans.

Objective: This study aimed to investigate scalp gamma-band oscillations (GBOs) induced by mechanical stimuli activating skin nociceptors before and after the induction of mechanical hypersensitivity using high-frequency electrical stimulation (HFS) of the skin.

Methods: In twenty healthy volunteers, we recorded the electroencephalogram during robot-controlled mechanical pinprick stimulation (512 mN) applied at the right ventral forearm before and after HFS.

Results: HFS induced a significant increase in mechanical pinprick sensitivity, but this increased pinprick sensitivity was, at the group level, not accompanied by a significant increase in GBOs.

Influence of skin type and laser wavelength on laser-evoked potentials.

Background: Infrared laser stimulation is a valuable tool in pain research, its primary application being the recording of laser-evoked brain potentials (LEPs). Different types of laser stimulators, varying in their skin penetrance, are likely to have a large influence on the LEPs, when stimulating different skin types. The aim of this study was to investigate how LEPs depend on laser type and skin location.

Comparison between pupillometry and numeric pain rating scale for pain assessments in communicating adult patients in the emergency department.

Objective: The adequate assessment of pain in the emergency department (ED) can be challenging. Two dynamic pupillary measures used in conscious subjects after a surgical procedure were previously shown to correlate to the magnitude of ongoing pain. The objective of this study was to test the ability of dynamic measures derived from pupillometry to evaluate pain intensity in conscious adult patients admitted to the ED.

Pain-free default mode network connectivity contributes to tonic experimental pain intensity beyond the role of negative mood and other pain-related factors.

Background: Alterations in the default mode network (DMN) connectivity across pain stages suggest a possible DMN involvement in the transition to persistent pain.

Aim: This study examined whether pain-free DMN connectivity at lower alpha oscillations (8-10 Hz) accounts for a unique variation in experimental peak pain intensity beyond the contribution of factors known to influence pain intensity.

Methods: Pain-free DMN connectivity was measured with electroencephalography prior to 1 h of capsaicin-evoked pain using a topical capsaicin patch on the right forearm.

Perceptual simultaneity between nociceptive and visual stimuli depends on their spatial congruence.

To protect our body against physical threats, it is important to integrate the somatic and extra-somatic inputs generated by these stimuli. Temporal synchrony is an important parameter determining multisensory interaction, and the time taken by a given sensory input to reach the brain depends on the length and conduction velocity of the specific pathways through which it is transmitted. Nociceptive inputs are transmitted through very slow conducting unmyelinated C and thinly myelinated Aδ nociceptive fibers.

The test-retest reliability of large and small fiber nerve excitability testing with threshold tracking.

Objective: Standard nerve excitability testing (NET) predominantly assesses Aα- and Aβ-fiber function, but a method examining small afferents would be of great interest in pain studies. Here, we examined the properties of a novel perception threshold tracking (PTT) method that preferentially activates Aδ-fibers using weak currents delivered by a novel multipin electrode and compared its reliability with NET.

Methods: Eighteen healthy subjects (mean age:34.

Confidence of probabilistic predictions modulates the cortical response to pain.

Pain typically evolves over time, and the brain needs to learn this temporal evolution to predict how pain is likely to change in the future and orient behavior. This process is termed temporal statistical learning (TSL). Recently, it has been shown that TSL for pain sequences can be achieved using optimal Bayesian inference, which is encoded in somatosensory processing regions.

Spatial summation of cold and warm detection: Evidence for increased precision when brisk stimuli are delivered over larger area.

Cold and warm stimuli delivered over a larger skin area tend to be more easily detected/elicit stronger sensations, a phenomenon referred to as spatial summation. The aim of the present study was to clarify how stimulation area affects thermal detection processes by evaluating whether increasing the stimulation area simply reduces the detection threshold or also reduces the uncertainty of the detection process. Psychometric functions were fitted to the detection performance of 16 healthy subjects.

Neural evidence for functional roles of tactile and visual feedback in the application of myoelectric prosthesis.

. The primary purpose of this study was to investigate the electrophysiological mechanism underlying different modalities of sensory feedback and multi-sensory integration in typical prosthesis control tasks..

High-speed heating of the skin using a contact thermode elicits brain responses comparable to CO laser-evoked potentials.

Objective: To compare nociceptive event-related brain potentials elicited by a high-speed contact-thermode vs an infrared CO laser stimulator.

Methods: Contact heat-evoked potentials (CHEPs) and CO laser-evoked potentials (LEPs) were recorded in healthy volunteers using a high-speed contact-thermode (>200 °C/s) and a temperature-controlled CO laser. In separate experiments, stimuli were matched in terms of target surface temperature (55 °C) and intensity of perception.

Olfactory Dysfunction Predicts Frailty and Poor Postoperative Outcome in Older Patients Scheduled for Elective Non-Cardiac Surgery.

Objectives: Frailty has been suggested to take part in the recently demonstrated link between olfactory dysfunction and overall mortality risk. Preoperative assessment of frailty is essential to detect the most vulnerable patients scheduled for surgery. The aim of this study was to evaluate whether olfactory dysfunction is a reliable predictor of preoperative frailty and postoperative outcome.

No evidence for an effect of selective spatial attention on the development of secondary hyperalgesia: A replication study.

Central sensitization refers to the increased responsiveness of nociceptive neurons in the central nervous system after repeated or sustained peripheral nociceptor activation. It is hypothesized to play a key role in the development of chronic pain. A hallmark of central sensitization is an increased sensitivity to noxious mechanical stimuli extending beyond the injured location, known as secondary hyperalgesia.

Characterization of vagus nerve stimulation-induced pupillary responses in epileptic patients.

Background: Modulation of the locus coeruleus (LC)-noradrenergic system is a key mechanism of vagus nerve stimulation (VNS). Activation of the LC produces pupil dilation, and the VNS-induced change in pupil diameter was demonstrated in animals as a possible dose-dependent biomarker for treatment titration.

Objective: This study aimed to characterize VNS-induced pupillary responses in epileptic patients.