Influence of low back pain and its remission on motor abundance in a low-load lifting task

Having an abundance of motor solutions during movement may be advantageous for the health of musculoskeletal tissues, given greater load distribution between tissues. The aim of the present study was to understand whether motor abundance differs between people with and without low back pain (LBP) during a low-load lifting task. Motion capture with electromyography (EMG) assessment of 15 muscles was performed on 48 participants [healthy control (con) = 16, remission LBP (rLBP) = 16, current LBP (cLBP) = 16], during lifting. Non-negative matrix factorization and uncontrolled manifold analysis were performed to decompose inter-repetition variability in the temporal activity of muscle modes into goal equivalent (GEV) and non-goal equivalent (NGEV) variabilities in the control of the pelvis and trunk linear displacements. Motor abundance occurs when the ratio of GEV to NGEV exceeds zero. There were significant group differences in the temporal activity of muscle modes, such that both cLBP and rLBP individuals demonstrated greater activity of muscle modes that reflected lumbopelvic coactivation during the lifting phase compared to controls. For motor abundance, there were no significant differences between groups. Individuals with LBP, including those in remission, had similar overall motor abundance, but use different activation profiles of muscle modes than asymptomatic people during lifting

Influence of experimental pain on the spatio-temporal activity of upper trapezius during dynamic lifting – An investigation using Bayesian spatio-temporal ANOVA

High-density surface electromyography (HDsEMG) provides a detailed analysis of a muscle’s spatial distribution of activity. We applied a Bayesian spatio-temporal statistical method to quantify how acute nociception and task repetition alters the upper trapezius instantaneous spatial distribution of activity during dynamic muscular contractions. Ten male adults performed repeated lifting of a 1 kg box between shelves positioned at hip and shoulder heights with a cycle time of 3 s for 50 cycles under four conditions: baseline, isotonic and hypertonic saline injections (nociception) to the right upper trapezius, and 15 min post injection. Activity of the right upper trapezius was measured using a 64-channel surface electrode grid. Statistical inference was performed using Integrated Nested Laplace Approximations (INLA), and significance was determined by a non-zero crossing of the Bayesian 95% credible intervals (CrI). The maximal decrease in activity after nociception was −38.1 µV [95% CrI −40.9 to −35.3] at 30% of the lift cycle when compared to baseline. The maximal reduction in muscle activity between the early and later phases of lifting in the presence of nociception was by 10.4 µV [95% CrI 8.2–12.6]. A more holistic understanding of muscle behaviour is achieved using spatio-temporal inference than traditional reductionist methods

Investigating the Causal Mechanisms of Symptom Recovery in Chronic Whiplash-associated Disorders Using Bayesian Networks

Objectives: The present study’s objective was to understand the causal mechanisms underpinning the recovery of individuals with whiplash-associated disorders (WAD). We applied Bayesian Networks (BN) to answer 2 study aims: (1) to identify the causal mechanism(s) of recovery underpinning neck-specific exercise (NSE), and (2) quantify if the cyclical pathway of the fear-avoidance model (FAM) is supported by the present data. Materials and Methods: We analyzed a prospective cohort data set of 216 individuals with chronic WAD. Fifteen variables were used to build a BN model: treatment group (NSE with or without a behavioral approach, or general physical activity), muscle endurance, range of motion, hand strength, neck proprioception, pain catastrophizing, fear, anxiety, depression, self-efficacy, perceived work ability, disability, pain intensity, sex, and follow-up time. Results: The BN model showed that neck pain reduction rate was greater after NSE compared with physical activity prescription (β=0.59 points per month [P<0.001]) only in the presence of 2 mediators: global neck muscle endurance and perceived work ability. We also found the following pathway of variables that constituted the FAM: anxiety, followed by depressive symptoms, fear, catastrophizing, self-efficacy, and consequently pain. Conclusions: e uncovered 2 mediators that explained the mechanisms of effect behind NSE, and proposed an alternative FAM pathway. The present study is the first to apply BN modelling to understand the causal mechanisms of recovery in WAD. In doing so, it is anticipated that such analytical methods could increase the precision of treatment of individuals with chronic WAD

The influence of musculoskeletal pain disorders on muscle synergies—A systematic review

Background Musculoskeletal (MSK) pain disorders represent a group of highly prevalent and often disabling conditions. Investigating the structure of motor variability in response to pain may reveal novel motor impairment mechanisms that may lead to enhanced management of motor dysfunction associated with MSK pain disorders. This review aims to systematically synthesize the evidence on the influence of MSK pain disorders on muscle synergies. Methods Nine electronic databases were searched using Medical Subject Headings and keywords describing pain, electromyography and synergies. Relevant characteristics of included studies were extracted and assessed for generalizability and risk of bias. Due to the significant heterogeneity, a qualitative synthesis of the results was performed. Results The search resulted in a total of 1312 hits, of which seven articles were deemed eligible. There was unclear consistency that pain reduced the number of muscle synergies. There were low consistencies of evidence that the synergy vector (W weights) and activation coefficient (C weights) differed in painful compared to asymptomatic conditions. There was a high consistency that muscle synergies were dissimilar between painful and asymptomatic conditions. Conclusions MSK pain alters the structure of variability in muscle control, although its specific nature remains unclear. Greater consistency in muscle synergy analysis may be achieved with appropriate selection of muscles assessed and ensuring consistent achievement of motor task outcomes. Synergy analysis is a promising method to reveal novel understandings of altered motor control, which may facilitate the assessment and treatment of MSK pain disorders

A network analysis reveals the interaction between fear and physical features in people with neck pain.

Although neck pain is known to be a complex and multifactorial condition characterised by the interplay between physical and psychological domains, a comprehensive investigation examining the interactions across multiple features is still lacking. In this study, we aimed to unravel the structure of associations between physical measures of neuromuscular function and fear of movement in people with a history of neck pain. One hundred participants (mean age 33.3 ± 9.4) were assessed for this cross-sectional study, and the neuromuscular and kinematic features investigated were the range of motion, velocity of neck movement, smoothness of neck movement, neck proprioception (measured as the joint reposition error), and neck flexion and extension strength. The Tampa Scale for Kinesiophobia was used to assess fear of movement. A network analysis was conducted to estimate the associations across features, as well as the role of each feature in the network. The estimated network revealed that fear of movement and neuromuscular/kinematic features were conditionally dependent. Higher fear of movement was associated with a lower range of motion, velocity, smoothness of neck movement, neck muscle strength, and proprioception (partial correlations between - 0.05 and - 0.12). Strong interactions were also found between kinematics features, with partial correlations of 0.39 and 0.58 between the range of motion and velocity, and between velocity and smoothness, respectively. The velocity of neck movement was the most important feature in the network since it showed the highest strength value. Using a novel approach to analysis, this study revealed that fear of movement can be associated with a spectrum of neuromuscular/kinematic adaptations in people with a history of neck pain

Clinical predictive modelling of post-surgical recovery in individuals with cervical radiculopathy: a machine learning approach

Prognostic models play an important role in the clinical management of cervical radiculopathy (CR). No study has compared the performance of modern machine learning techniques, against more traditional stepwise regression techniques, when developing prognostic models in individuals with CR. We analysed a prospective cohort dataset of 201 individuals with CR. Four modelling techniques (stepwise regression, least absolute shrinkage and selection operator [LASSO], boosting, and multivariate adaptive regression splines [MuARS]) were each used to form a prognostic model for each of four outcomes obtained at a 12 month follow-up (disability—neck disability index [NDI]), quality of life (EQ5D), present neck pain intensity, and present arm pain intensity). For all four outcomes, the differences in mean performance between all four models were small (difference of NDI &lt; 1 point; EQ5D &lt; 0.1 point; neck and arm pain &lt; 2 points). Given that the predictive accuracy of all four modelling methods were clinically similar, the optimal modelling method may be selected based on the parsimony of predictors. Some of the most parsimonious models were achieved using MuARS, a non-linear technique. Modern machine learning methods may be used to probe relationships along different regions of the predictor space

Benefits and resource implications of family meetings for hospitalized palliative care patients: research protocol.

BACKGROUND:Palliative care focuses on supporting patients diagnosed with advanced, incurable disease; it is 'family centered', with the patient and their family (the unit of care) being core to all its endeavours. However, approximately 30-50% of carers experience psychological distress which is typically under recognised and consequently not addressed. Family meetings (FM) are recommended as a means whereby health professionals, together with family carers and patients discuss psychosocial issues and plan care; however there is minimal empirical research to determine the net effect of these meetings and the resources required to implement them systematically. The aims of this study were to evaluate: (1) if family carers of hospitalised patients with advanced disease (referred to a specialist palliative care in-patient setting or palliative care consultancy service) who receive a FM report significantly lower psychological distress (primary outcome), fewer unmet needs, increased quality of life and feel more prepared for the caregiving role; (2) if patients who receive the FM experience appropriate quality of end-of-life care, as demonstrated by fewer hospital admissions, fewer emergency department presentations, fewer intensive care unit hours, less chemotherapy treatment (in last 30 days of life), and higher likelihood of death in the place of their choice and access to supportive care services; (3) the optimal time point to deliver FM and; (4) to determine the cost-benefit and resource implications of implementing FM meetings into routine practice.METHODS:Cluster type trial design with two way randomization for aims 1-3 and health economic modeling and qualitative interviews with health for professionals for aim 4.DISCUSSION:The research will determine whether FMs have positive practical and psychological impacts on the family, impacts on health service usage, and financial benefits to the health care sector. This study will also provide clear guidance on appropriate timing in the disease/care trajectory to provide a family meeting.<br/