Human Studies

Little is known about long-term physical activity (PA) maintenance in those with chronic widespread pain (CWP) following an exercise intervention. This study examined PA over time to identify the existence and characteristics of subgroups following distinct PA trajectories.

This randomized controlled trial investigated the efficacy of cognitive functional therapy (CFT) compared with manual therapy and exercise (MT-EX) for people with non-specific chronic low back pain (NSCLBP) at 3-year follow-up.

A growing body of evidence suggests that chronic pain is associated with perceptual changes, such as impaired tactile acuity and laterality judgements. A recent study on low back pain showed that tactile acuity was reduced immediately after acute pain induction. Biologically, acute pain should lead to enhanced rather than disruptive changes in tactile acuity to meaningfully respond to potentially damaging nociceptive stimuli. In this double-blinded experiment, 30 healthy volunteers attended three experimental sessions (injection, sham-injection and control condition) separated by one week each, to investigate the effect of acute nociception on tactile precision and laterality judgements. In the real injection condition, acute pain was induced by hypertonic saline solution injected into the mid portion of the trapezius muscle. Tactile acuity (two-point discrimination and an estimation task) and laterality judgements were measured before and during pain perception. In the sham condition the injection was mimicked by a sham procedure (without piercing the skin), in the control condition no intervention took place. Results showed that tactile acuity remained intact (P=0.92) indicating that experimentally induced neck pain did not affect tactile precision. The time needed to complete the laterality judgement task improved over-time in all conditions reflecting a learning effect (P=0.05), We conclude that acute neck pain does not result in perceptual distortions, possibly reflecting a higher protection demand for the neck, a body region in close anatomical proximity to neural centers responsible for vital functions. This data -in the context of existing evidence- indicates that tactile acuity may respond differently to noxious stimulation in different anatomical regions. Perspective: In this study, a sensory adaptation to acute neck pain was investigated. It was found that experimental neck pain did not elicit changes in the sensory axis leaving tactile acuity intact in otherwise healthy subjects. These data support site-specific sensory adaptation to pain.

Widespread pain is a common comorbidity in several chronic diseases and is suspected to be caused by the underlying disease that has provoked a state of central sensitization. However, this argument is currently limited by evidence that has not sufficiently captured the temporal nature of the relationship between diagnosis of the underlying disease and onset of widespread pain. The aim of this study was to investigate whether patients with rheumatoid arthritis (RA), endometriosis or inflammatory bowel disease (IBD) have a higher risk of developing widespread pain (fibromyalgia or chronic widespread pain [CWP]).

In this clinical and neurophysiological study using a novel cold stimulator we aim at investigating whether cold evoked potentials may prove to be a reliable diagnostic tool to assess trigeminal small-fibre function.Using a novel device consisting of micro-Peltier elements, we recorded cold evoked potentials after stimulating the supraorbital and perioral regions and the hand dorsum in 15 healthy participants and in two patients with exemplary facial neuropathic pain conditions. We measured peripheral conduction velocity at the upper arm and studied the brain generators using source analysis. In healthy participants and patients, we also compared cold evoked potentials with laser evoked potentials.In the healthy participants, cold stimulation evoked reproducible scalp potentials, similar to those elicited by laser pulses, though with a latency of about 30 ms longer. The mean peripheral conduction velocity, estimated at the upper arm, was 12.7 m/s. The main waves of the scalp potentials originated from the anterior cingulate gyrus and were preceded by activity in the bilateral opercular regions and bilateral dorso-lateral frontal regions. Unlike laser stimulation, cold stimulation evoked scalp potential of similar amplitude across perioral, supraorbital and hand dorsum stimulation. In patients with facial neuropathic pain, cold evoked potential recording showed the selective damage of cold pathways providing complementary information to laser evoked potential recording.Our clinical and neurophysiological study shows that this new device provides reliable information on trigeminal small-fibres mediating cold sensation, and might be useful for investigating patients with facial neuropathic pain associated with a distinct damage of cold-mediating fibres.