Association Between Symptoms of Central Sensitization and Cognitive Behavioral Factors in People With Chronic Nonspecific Low Back Pain: A Cross-sectional Study.

OBJECTIVE: The objective of this cross-sectional study was to analyze the relationship between symptoms of central sensitization (CS) and important cognitive behavioral and psychosocial factors in a sample of patients with chronic nonspecific low back pain. METHODS: Participants with chronic nonspecific low back pain for at least 3 months were included in the study. They completed several questionnaires and a functional test. Pearson's correlation was used to analyze associations between symptoms of CS and pain behavior, functioning, pain, pain catastrophizing, kinesiophobia, and illness perceptions. Additionally, a between-group analysis was performed to compare patients with and without clinically relevant symptoms of CS. RESULTS: Data from 38 participants were analyzed. Significant associations were found between symptoms of CS and all other outcomes, especially current pain (r = 0.510, P = .001), mean pain during the past 7 days (r = 0.505, P = .001), and pain catastrophizing (r = 0.518, P = .001). Patients with clinically relevant symptoms of CS scored significantly worse on all outcomes compared with persons without relevant symptoms of CS, except on functioning (P = .128). CONCLUSIONS: Symptoms of CS were significantly associated with psychosocial and cognitive behavioral factors. Patients exhibiting a clinically relevant degree of symptoms of CS scored significantly worse on most outcomes, compared with the subgroup of the sample with fewer symptoms of CS.

Auto-Targeted Neurostimulation Is Not Superior to Placebo in Chronic Low Back Pain: A Fourfold Blind Randomized Clinical Trial.

BACKGROUND: Myofascial trigger points (MTrPs) are common in people with musculoskeletal pain and may play a role in chronic nonspecific low back pain (CLBP). One of the potential treatments of MTrPs is the Nervomatrix Soleve® auto-targeted neurostimulation device, providing targeted transcutaneous electrical nerve stimulation (TENS) to MTrPs in the lower back muscles. To date, no controlled studies have evaluated the effectiveness of this device for the pain management of this population. OBJECTIVE: To examine whether the Nervomatrix Soleve® auto-targeted neurostimulation device is superior over placebo for the treatment of CLBP. STUDY DESIGN: A fourfold-blind randomized controlled trial was conducted. SETTING: Brussels University Hospital, health care centers and pharmacies around Belgium. METHODS: Participants with CLBP for at least 3 months were randomly assigned to the experimental (the Nervomatrix Soleve® auto-targeted neurostimulation device providing TENS-stimulation and mechanical pressure) or placebo group (the Nervomatrix Soleve® auto-targeted neurostimulation device providing mechanical pressure alone without current). The treatment protocol in both groups consisted of 6 treatment sessions per patient. Participants were evaluated at baseline prior to the intervention, immediately following treatment, and at one month follow-up. Pain and pain behavior (steps climbed) were assessed as primary outcome measures. Secondary outcome measures were pain functioning, health beliefs, symptoms of central sensitization, pain catastrophizing, and kinesiophobia. RESULTS: In total, 39 participants were included in the study. Participants in both groups improved significantly for pain and functioning, but no significant differences were observed between groups. These improvements were not clinically meaningful for any of the reported measures. The health beliefs changed significantly in both groups (P < 0.05), with superior results at follow-up in the placebo group. LIMITATIONS: The follow-up period is limited to one month. CONCLUSIONS: Treatment of MTrPs with the Nervomatrix Soleve® auto-targeted neurostimulation device in patients with CLBP does not result in a better outcome than placebo-treatment in terms of pain, pain behavior, functioning, central sensitization, pain catastrophizing, and health beliefs.

Prevalence, Incidence, Localization, and Pathophysiology of Myofascial Trigger Points in Patients With Spinal Pain: A Systematic Literature Review.

OBJECTIVE: A systematic review was performed to evaluate the existing evidence related to the prevalence, incidence, localization, and pathophysiology of myofascial trigger points (MTrPs) in patients with spinal (back and neck) pain. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed in 2 electronic databases (PubMed and Web of Science) using predefined keywords regarding MTrPs and spinal pain. A "PICOS" questionnaire was used to set up the search strategies and inclusion criteria. Full-text reports concerning MTrPs in patients with back or neck pain, which described their prevalence, incidence, location, or underlying physiopathology were included and screened for methodological quality by 3 independent researchers. Each study was assessed for risk of bias using a checklist derived from the Web site of the Dutch Cochrane Centre. RESULTS: Fourteen articles were retrieved for quality assessment and data extraction. Studies reporting the incidence of MTrPs in patients with spinal pain were lacking. Within spinal pain, patients with neck pain were found to have the highest prevalence rates of MTrPs. The trapezius descendens, levator scapulae, and suboccipitales muscles were the most prevalent locations for active MTrPs in patients with neck pain. Latent MTrPs were present in asymptomatic people, but no significant differences were found in the prevalence rate of latent MTrPs between patients with spinal (neck) pain and healthy controls. The only study investigating prevalence of MTrPs in different localizations of the same muscle reported no significant differences in prevalence between active and latent MTrPs within the trapezius descendens muscle. Studies examining pathophysiological mechanisms underlying MTrPs demonstrated an acidic environment, high concentration of algogenic/inflammatory substances, stiffer muscle tissue, retrograde diastolic blood flows, spontaneous muscle activity at rest, and loss of muscle contractibility in muscles with MTrPs. Altered central processing was also found to play a role in the development of MTrPs. CONCLUSIONS: Myofascial trigger points are a prevalent clinical entity, especially in patients with neck pain. Evidence was not found to support or deny the role of MTrPs in other spinal pain. Compelling evidence supports local mechanisms underlying MTrPs. Future research should unravel the relevance of central mechanisms and investigate the incidence of MTrPs in patients with spinal pain.

Mining minimal motif pair sets maximally covering interactions in a protein-protein interaction network.

Correlated motif covering (CMC) is the problem of finding a set of motif pairs, i.e., pairs of patterns, in the sequences of proteins from a protein-protein interaction network (PPI-network) that describe the interactions in the network as concisely as possible. In other words, a perfect solution for CMC would be a minimal set of motif pairs that describes the interaction behavior perfectly in the sense that two proteins from the network interact if and only if their sequences match a motif pair in the minimal set. In this paper, we introduce and formally define CMC and show that it is closely related to the red-blue set cover (RBSC) problem and its weighted version (WRBSC)--both well-known NP-hard problems for that there exist several algorithms with known approximation factor guarantees. We prove the hardness of approximation of CMC by providing an approximation factor preserving reduction from RBSC to CMC. We show the existence of a theoretical approximation algorithm for CMC by providing an approximation factor preserving reduction from CMC to WRBSC. We adapt the latter algorithm into a functional heuristic for CMC, called CMC-approx, and experimentally assess its performance and biological relevance. The implementation in Java can be found at >http://bioinformatics.uhasselt.be.

SLIDER: a generic metaheuristic for the discovery of correlated motifs in protein-protein interaction networks.

Correlated motif mining (cmm) is the problem of finding overrepresented pairs of patterns, called motifs, in sequences of interacting proteins. Algorithmic solutions for cmm thereby provide a computational method for predicting binding sites for protein interaction. In this paper, we adopt a motif-driven approach where the support of candidate motif pairs is evaluated in the network. We experimentally establish the superiority of the Chi-square-based support measure over other support measures. Furthermore, we obtain that cmm is an np-hard problem for a large class of support measures (including Chi-square) and reformulate the search for correlated motifs as a combinatorial optimization problem. We then present the generic metaheuristic slider which uses steepest ascent with a neighborhood function based on sliding motifs and employs the Chi-square-based support measure. We show that slider outperforms existing motif-driven cmm methods and scales to large protein-protein interaction networks. The slider-implementation and the data used in the experiments are available on http://bioinformatics.uhasselt.be.