Central Sensitization and Physical Functioning in patients with Chronic Low Back Pain

Chronic low back pain is one of the most disabling conditions worldwide and has a major negative impact on individual’s functioning (i.e. mobility and self-care, social relationships, work and leisure). In a relevant subgroup of individuals with chronic low back pain, central sensitization (CS) can be present, leading to an amplified pain experience. This thesis explores the involvement of CS in the functioning of patients with chronic low back pain and, additionally, the measurement methods to assess CS and functioning. To this purpose six studies were performed. The results revealed associations between CS and functioning, although these associations were few and diverse. Also, the measurement methods to assess CS reported no associations between them. Lastly, a maximal cardiopulmonary exercise test was found to be safe, feasible, pain tolerable and partly associated with other measurement methods of functioning. Based on the results, it was concluded that CS can be involved in the functioning of patients with CLBP, although it does not seem to play a crucial role

Maximal cardiopulmonary exercise test in patients with chronic low back pain: feasibility, tolerance and relation with central sensitization. An observational study:feasibility, tolerance and relation with central sensitization. An observational study

PURPOSE: To analyze the feasibility of and pain-related tolerance to a maximal cardiopulmonary exercise test (CPET), and the relationship between the aerobic capacity and central sensitization (CS) in patients with chronic low back pain (CLBP).METHODS: An observational study, combining a cross-sectional and a prospective 24-hour follow-up was performed. Participants underwent a maximal CPET on a cycle ergometer and were assessed with three measures of CS (CS Inventory, quantitative sensory testing and heart rate variability). Before the CPET, immediately afterwards and 24 h after, the Pain Response Questionnaire (PRQ) was filled out. The CPET was considered feasible when &gt;80% performed maximally, and tolerable when &lt;20% reported relevant pain increase, body reactions and additional pain medication use in the PRQ. Multiple regression analyses were applied to assess the relationship between the aerobic capacity (VO2max) and CS measures, corrected for confounders.RESULTS: 74 patients with CLBP participated of which 30 were male, mean age was 40.4 years (SD: 12.4) and median VO2max was 23.9 ml/kg/min (IQR: 18.2-29.4). CPET was completed by 92%. No serious adverse events occurred. A relevant pain increase was reported in the upper legs by 40% immediately after CPET and by 28% 24 h afterwards, 27% reported body reactions after 24 h, and 22% increased pain medication use 24 h after CPET. Very weak and not significant relations (rpartial=-0.21 to 0.05; p &gt; 0.10) were observed between aerobic capacity and CS measures.CONCLUSIONS: A maximal CPET is feasible in patients with CLBP. Most, but not all, tolerated it well. CS was not related to aerobic capacity.Implications for rehabilitationMaximal CPET is feasible in patients with CLBP and well tolerated by most patients.Maximal CPET can be safely applied to assess the aerobic capacity of patients with CLBP.Aerobic capacity is unrelated to central sensitization.Outcomes of a maximal CPET and the pain response to straining activity can be used to provide valid information for the decision-making of exercise therapy.</p

Central sensitization and functioning in patients with chronic low back pain:A cross-sectional and longitudinal study

BACKGROUND: Central sensitization (CS) is present in a subgroup of patients with chronic low back pain (CLBP). Studies on the relationship between CS and functioning have limited operationalizations of CS and functioning. OBJECTIVE: To determine whether CS was related to functioning in patients with CLBP (cross-sectional); and to determine whether changes in CS were related to changes in functioning (longitudinal). METHODS: An observational prospective cohort study with data collected at baseline and discharge of an interdisciplinary pain rehabilitation program was executed. CS indicators: CS Inventory part A (CSI-A), quantitative sensory testing (QST), root mean square of successive differences of heart-rate variability (RMSSD). Functioning measures: lifting capacity, physical functioning subscale of Rand36 (Rand36-PF), Work Ability Score (WAS), Pain Disability Index (PDI). Main analyses included correlation and multiple regression controlling for confounders; cross-sectional with baseline data and longitudinal with deltas ([Formula: see text]). RESULTS: 76 patients with primary CLBP participated at baseline and 56 at discharge. Most associations were weak (cross-sectional [Formula: see text] [Formula: see text] 0.30–0.24; longitudinal [Formula: see text] [Formula: see text] 0.37–0.44). Cross-sectional multiple regression significant associations: mechanical pain threshold-QST and lifting capacity ([Formula: see text] [Formula: see text] 0.39), parasympathetic/vagal tone-RMSSD and physical functioning–Rand36-PF ([Formula: see text] 0.26). Longitudinal multiple regression significant associations: [Formula: see text] parasympathetic/vagal tone-RMSSD and [Formula: see text] lifting capacity ([Formula: see text] 0.48), [Formula: see text] CSI-A and [Formula: see text] disability-PDI ([Formula: see text] 0.36). Cross-sectional and longitudinal final regression models explained 24.0%–58.3% and 13.3%–38.0% of total variance. CONCLUSION: CS was weakly related to functioning, and decreases in CS were weakly-moderately related to increases in functioning

Lifting capacity is associated with central sensitization and non-organic signs in patients with chronic back pain

Purpose: To analyze the associations between lifting capacity, and central sensitization (CS) and non-organic signs (NOS) in patients with chronic back pain (CBP) attending vocational rehabilitation. Materials and methods: Cross-sectional observational multicenter study among patients with CBP undergoing a return to work assessment within care as usual. Main analyses: step 1: partial correlation between lifting capacity, and CS, NOS, and additional variables; step 2: multiple regression in stepwise forward method for dependent variable lifting capacity, and for independent variables CS and NOS, and additional variables significant (p < 0.05) at step 1. All analyses were controlled for sex. Results: Fifty-six patients of mean age 42.5 years and 59% women participated in the study. Correlations between lifting capacity and CS and NOS were r = –0.53 and r = –0.50, respectively. CS and NOS, as well as age and sex, contributed significantly to the final regression model, which explained 57.6% of variance. Conclusions: After controlling for confounders, CS and NOS were negatively associated with lifting capacity in patients with CBP. Explained variance was substantially higher than previously reported studies.Implications for Rehabilitation The identification of central sensitization and non-organic signs (NOS) in patients with chronic back pain can alert clinicians about central nervous system being in a hypersensitive state and about pain behavior. Central sensitization and NOS are relevant determinants of lifting capacity. Better understanding of the factors affecting lifting capacity lead to better design and tailoring of interventions, resulting in optimized vocational rehabilitation programs and faster return to work

A pilot study in the association between Waddell Non-organic Signs and Central Sensitization

Study design: A cross-sectional observational multicenter pilot-study was performed within care as usual in three rehabilitation centers in the Netherlands. Objective: To explore the relationship between Waddell Non-organic Signs (NOS) and Central Sensitization (CS) in patients with chronic back pain. Summary of background data: A possible relationship between NOS and CS is theoretically plausible, but it has never been tested. Methods: A cross-sectional observational multicenter pilot-study was performed in three rehabilitation centers in the Netherlands. Patients with chronic back pain were included. Main measures were Waddell's NOS, a battery of eight clinical tests performed during a physical examination, and Central Sensitization Inventory (CSI), a questionnaire measuring symptoms originating from CS. Analyses included Spearman correlation and univariate multiple regression analysis with NOS as dependent variable, CSI as independent, and controlled for confounders (psychosocial variables). Results: Data of n = 56 patients (59% female, mean age 42.6 years) were obtained. Correlation between NOS and CSI was rs = 0.34 (p = 0.01). After controlling for confounders, CSI did not independently predict NOS. Conclusion: In this pilot study, CS was moderately related to NOS, but CS did not independently contribute to NOS after controlling for confounders. The results suggest that NOS may not exclusively be non-organic tests, although questions remain. The results of this pilot study can help to develop larger studies to allow replication and more detailed analyses

Association between central sensitization and gait in chronic low back pain:Insights from a machine learning approach

BACKGROUND: Central sensitization (CS) is often present in patients with chronic low back pain (CLBP). Gait impairments due to CLBP have been extensively reported; however, the association between CS and gait is unknown. The present study examined the association between CS and CLBP on gait during activities of daily living. METHOD: Forty-two patients with CLBP were included. CS was assessed through the Central Sensitization Inventory (CSI), and patients were divided in a low and high CS group (23 CLBP- and 19 CLBP+, respectively). Patients wore a tri-axial accelerometer device for one week. From the acceleration signals, gait cycles were extracted and 36 gait outcomes representing quantitative and qualitative characteristics of gait were calculated. A Random Forest was trained to classify CLBP- and CLBP + based on the gait outcomes. The maximum Youden index was computed to measure the diagnostic test's ability and SHapley Additive exPlanations (SHAP) indexed the gait outcomes' importance to the classification model. RESULTS: The Random Forest accurately (84.4%) classified the CLBP- and CLBP+. Youden index was 0.65, and SHAP revealed that the gait outcomes' important to the classification model were related to gait smoothness, stride frequency variability, stride length variability, stride regularity, predictability, and stability. CONCLUSIONS: CLBP- and CLBP + patients had different motor control strategies. Patients in the CLBP- group presented with a more "loose control", with higher gait smoothness and stability, while CLBP + patients presented with a "tight control", with a more regular, less variable, and more predictable gait pattern

Maximal aerobic capacity is associated with lifting capacity, but not with self-reported functioning measures in patients with primary chronic low back pain:a cross-sectional study

Objective Maximal exercise testing is considered the gold standard to assess (V)over dotO(2)max. However, maximal exercise testing was previously deemed unfeasible and unsafe in chronic low back pain (CLBP) patients. Consequently, most previous studies on aerobic capacity and functioning in patients with CLBP were performed with submaximal testing protocols. A recent study demonstrated the safety, feasibility and tolerance of maximal exercise testing in patients with CLBP. Therefore, the relation between aerobic capacity and functioning should be reevaluated. This cross-sectional study aims to determine the relationship between maximal aerobic capacity and four measures of functioning: lifting capacity, work ability, pain-related disability and physical functioning in patients with CLBP. Methods The maximal aerobic capacity of patients with CLBP was assessed with a maximal cardiopulmonary exercise test. Functioning was measured with a floor-to-waist lifting capacity test and three questionnaires: Work Ability Score, Pain Disability Index and Physical Functioning subscale of RAND-36. The associations between maximal aerobic capacity and each of the functioning measures were analysed with multiple linear regression analyses while controlling for potential confounders. Results Data of n=74 patients with CLBP were analysed. After controlling for potential confounders, maximal aerobic capacity was moderately associated with lifting capacity (beta=0.32, p=0.006), but not with any of the other functioning measures (beta=-0.08 to 0.12, p>0.288). Conclusion A higher level of maximal aerobic capacity is moderately associated with a higher lifting capacity, but not with self-reported work ability, pain-related disability and physical functioning

Central Sensitisation and functioning in patients with chronic low back pain: protocol for a cross-sectional and cohort study

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Do rehabilitation patients with chronic low back pain meet World Health Organisation's recommended physical activity levels?

Purpose: Primary: to analyse the time that patients with chronic low back pain (CLBP) admitted to pain rehabilitation spent on moderate to vigorous physical activity (MVPA) and compare this to the WHO recommen-dations. Secondary: to explore factors that might differentiate between those who do and do not meet the recommendations. Materials and methods: A Cross-sectional study embedded in secondary interdisciplinary rehabilitation of adults with CLBP. PA was measured with a tri-axial accelerometer for 1 week during admission phase. Time spent in each PA level was calculated. MVPA was also analysed in >= 10 min bouts. Results: Complete datasets of 4-6 days recorded accelerometery of n = 46 patients were analysed. Time spent in MVPA was on average 6.0% per day. MVPA per day in >= 10-min bouts occurred on average 0.8 times per day (sd = 0.9; min-max 0-4). Percentage of patients meeting the recommended level of MVPA was 21.7% (10/46) and 84.8% (39/46) for the 2010 and 2020 recommendations, respectively. Most demographic and clinical variables did not seem to differentiate between those who met the WHO recommendations, and those who did not. Conclusion: The minority of the patients (22%) met the WHO recommended MVPA level of 2010. The more lenient recommendation of 2020 was met by 85%

Age-related differences in women's foot shape

Purpose: Describe age-related differences in women's foot shape using a wide range of measurements and ages. Study design: Cross-sectional, observational study. Main outcome measurements: Six foot-shape measurements of each foot: foot lengths, ball widths, ball circumferences, low instep circumferences, high instep circumferences, and heel instep circumference. Results: 168 women from 20 to over 80 years of age, divided into seven age categories, were included. Older women had significantly greater foot-shape measurements, even after adjusting for Body Mass Index. Ball widths increased 3.1-4.0mm per decade, ball circumferences 5.6-7.4 mm per decade, high instep circumferences 0.4-4.8 mm per decade, and heel instep circumferences 1.8-1.9 mm per decade. Ball widths, ball circumferences, and left high instep circumference plateaued in the 70-75 years-of-age category, and decreased in the oldest age category. For low instep circumference, age did not prevail significantly over Body Mass Index. Foot length was not associated with age. Conclusion: This study described women's progressive foot-shape changes with age. The findings provide a better understanding of foot-shape changes, mainly found in the forefoot. It demonstrates that for a good fit, shoe design for older adults and for younger adults should differ. (C) 2016 Elsevier Ireland Ltd. All rights reserved