Headache production during physical examination in patients with and without headache attributed to a whiplash injury: A case-control study.

BACKGROUND: Provocation of headache on physical examination of the neck may reflect a role of cervical structures in the presence of acute whiplash-associated headache (WAH). OBJECTIVE: To determine differences in headache provocation during physical tests in people with and without WAH after a whiplash injury. DESIGN: Case-control study. METHODS: Forty-seven people with acute whiplash-associated disorders participated, 28 with WAH. Passive accessory intervertebral movement over the tubercle of C1, the spinous processes of C2-C3 and facet joints of C0-C4, the flexion-rotation test (FRT), manual palpation of cranio-cervical muscles and the upper limb neurodynamic test + cranio-cervical flexion were assessed bilaterally twice by a blinded examiner; headache provocation was determined. Cohen's kappa and Chi-squared were determined to evaluate the intra-rater reliability of test results and differences between groups, respectively. A logistic regression model was also performed. RESULTS: Intra-rater reliability of headache provocation was good or excellent for most tests. Significant differences between groups were found with higher positive tests in WAH for the assessment of C2 (68%), the most painful side of C0-C1 (57%), C1-C2 (75%) and C2-C3 (53%), most (79%) and least (25%) restricted sides of the FRT, and manual palpation of the most painful side for the trapezius (53%), masseter (50%) and temporalis (46%) muscles. Provocation of headache during the assessment of C2 and C1-C2 on the most painful side demonstrated the highest association with WAH. CONCLUSION: Mechanical provocation of headache is more frequent in people with WAH than in those without headache soon after a whiplash injury.

Headache features in people with whiplash associated disorders: A scoping review.

BACKGROUND: Whiplash-associated headache (WAH) is one of the most common symptoms after a whiplash injury, leading to high disability. Nevertheless, the clinical characteristics of WAH have not been well described. OBJECTIVE: To synthesise the existing literature on the clinical characteristics of WAH. DESIGN: Scoping review. METHODS: The protocol for this scoping review was registered in Open Science Framework and the PRISMA extension for Scoping Reviews tool was used to ensure methodological and reporting quality. A systematic search was conducted in PubMed, EMBASE, CINAHL, Web of Science and Scopus. The search was performed by one author and the screening of articles was conducted by two authors independently. RESULTS: A total of 11363 articles were initially identified and finally 26 studies were included in the review. Headache intensity was the most commonly reported feature. Headache duration, frequency and location were also reported in at least four studies. Few studies reported physical impairments that may be related to the presence of WAH. A differentiation with concussion characteristics was only performed in eight studies. CONCLUSION: WAH appears to be of mild to moderate intensity, typically with episodes of short duration which is commonly experienced in the occipital region amongst other regions, and with a tendency to reduce in intensity over time.

Supervised exercise with or without laser-guided feedback for people with non-specific chronic low back pain. A randomized controlled clinical trial.

BACKGROUND: Among the most effective therapeutic interventions in non-specific chronic low back pain (NSCLBP), clinical practice guidelines highlight exercise therapy and patient education; However, regarding the combined intervention of exercise and Pain Neuroscience Education (PNE), there is no consensus on the most effective form of exercise. OBJETIVE: To find out what changes occurred after the application of two exercise modalities [Supervised Exercise (SE) and Laser-Guided Exercise (LGE)] and PNE on pain, pain pressure thresholds, disability, catastrophizing, kinesiophobia and lumbar proprioception in subjects with NSCLBP. METHODS: Single-blind randomized clinical controlled trial. 60 subjects with NSCLBP. Both groups performed a a total of 16 therapeutic exercise sessions and 8 Pain Neuroscience Education sessions. With the Laser-Guided Exercise Therapy group performing laser-guided exercises. RESULTS: A significant decrease was observed for pain intensity for both groups between baseline and post-intervention and the 3 month follow-up (p < 0.001). There was a significant between-group difference between baseline and post-intervention scores in terms of pain intensity and kinesiophobia in favour of the LGE group. CONCLUSION: Supervised exercise with or without laser feedback, when combined with PNE, reduces pain intensity, disability, pain catastrophizing, kinesiophobia and improves proprioception and PPTs in patients with NSCLBP. At a 3-month follow-up, the combination of LGE plus PNE is most effective for reducing pain intensity.

Physical testing in patients with acute whiplash-associated disorders: A within session test-retest reliability study.

BACKGROUND: People with whiplash-associated disorders (WAD) commonly present with a variety of physical impairments. However, the reliability of physical tests has not been established for patients with acute WAD. OBJECTIVE: To assess test-retest reliability of different physical tests in acute WAD. DESIGN: Intra-rater test-retest reliability. METHODS: Patients with acute WAD were recruited. Physical tests were used to evaluate articular, muscular and neural systems in two blocks of measurements separated by 10 min. Bland-Altman plots were performed to assess intrarater agreement, which included calculation of the mean difference (d) between rates, the 95% CI for d, the standard deviation of the differences and the 95% limits of agreement. Reliability was calculated via the standard error of measurement, the minimal detectable change, percent of agreement, the intraclass-correlation coefficient, and kappa coefficient. RESULTS: 47 patients participated. Test-retest reliability was excellent or good for almost all measures, except for extension ROM, ULTT for the radial nerve, and active cervical extension and upper cervical rotation performed in 4-point kneeling, which presented moderate reliability. Systematic bias was found in cervical ROM in flexion, left and right lateral-flexion, left and right rotation; left ULTT for radial nerve; right trapezius, suboccipitalis and temporalis muscles, left temporalis; C3, both sides of C1-C2, left C3-C4. CONCLUSION: The majority of physical tests achieved good or excellent test-retest intra-rater reliability when tested in patients with acute WAD. Findings must be considered with caution for those tests which demonstrated systematic bias. Additional research is warranted to evaluate inter-rater reliability.

Trunk stability in fatiguing frequency-dependent lifting activities.

BACKGROUND: Work-related low-back disorders (WLBDs) are one of the most frequent and costly musculoskeletal conditions. It has been showed that WLBDs may occur when intervertebral or torso equilibrium is altered by a biomechanical perturbations or neuromuscular control error. The capacity to react to such disturbances is heavily determined by the spinal stability, provided by active and passive tissues and controlled by the central nervous system. RESEARCH QUESTION: This study aims to investigate trunk stability through the Lyapunov's maximum exponent during repetitive liftings in relation to risk level, as well as to evaluate its ability to discriminate these risk levels. METHODS: Fifteen healthy volunteers performed fatiguing lifting tasks at three different frequencies corresponding to low, medium, and high risk levels according to the National Institute for Occupational Safety and Health (NIOSH) equation. We investigated changes in spinal stability during fatiguing lifting tasks at different risk levels using the maximum Lyapunov's index (λMax) computed from trunk accelerations recorded by placing three IMUs at pelvis, lower and upper spine levels. A two-way repeated-measures ANOVA was performed to determine if there was any significant effect on λMax among the three risk levels and the time (start, mid, and end of the task). Additionally, we examined the Pearson's correlation of λMax with the trunk muscle co-activation, computed from trunk sEMG. RESULTS: Our findings show an increase in trunk stability with increasing risk level and as the lifting task progressed over time. A negative correlation between λMax and trunk co-activation was observed which illustrates that the increase in spinal stability could be partially attributed to increased trunk muscle co-activation. SIGNIFICANCE: This study highlights the possibility of generating stability measures from kinematic data as risk assessment features in fatiguing tasks which may prove useful to detect the risk of developing work-related low back pain disorders and allow the implementation of early ergonomic interventions.

APOE3 Christchurch modulates tau phosphorylation and ß-catenin/Wnt/Cadherin signaling in induced pluripotent stem cell-derived cerebral organoids from Alzheimer's cases.

Alzheimer's disease (AD) is the most common cause of dementia among older adults. APOE3 Christchurch (R136S, APOE3Ch ) variant homozygosity was reported in an individual with extreme resistance to autosomal dominant AD due to the PSEN1 E280A mutation. This subject had a delayed clinical age at onset and resistance to tauopathy and neurodegeneration despite extremely high amyloid plaque burden. We established induced pluripotent stem (iPS) cell-derived cerebral organoids from this resistant case and from a non-protected kindred control (with PSEN1 E280A and APOE3/3 ). We used CRISPR/Cas9 gene editing to successfully remove the APOE3Ch to wild type in iPS cells from the protected case and to introduce the APOE3Ch as homozygote in iPS cells from the non-protected case to examine causality. We found significant reduction of tau phosphorylation (pTau 202/205 and pTau396) in cerebral organoids with the APOE3Ch variant, consistent with the strikingly reduced tau pathology found in the resistant case. We identified Cadherin and Wnt pathways as signaling mechanisms regulated by the APOE3Ch variant through single cell RNA sequencing in cerebral organoids. We also identified elevated ß-catenin protein, a regulator of tau phosphorylation, as a candidate mediator of APOE3Ch resistance to tauopathy. Our findings show that APOE3Ch is necessary and sufficient to confer resistance to tauopathy in an experimental ex-vivo model establishing a foundation for the development of novel, protected case-inspired therapeutics for tauopathies, including Alzheimer's.

Reliability of high-density surface electromyography for assessing characteristics of the thoracic erector spinae during static and dynamic tasks.

PURPOSE: To establish intra- and inter-session reliability of high-density surface electromyography (HDEMG)-derived parameters from the thoracic erector spinae (ES) during static and dynamic goal-directed voluntary movements of the trunk, and during functional reaching tasks. METHODS: Twenty participants performed: 1) static trunk extension, 2) dynamic trunk forward and lateral flexion, and 3) multidirectional functional reaching tasks on two occasions separated by 7.5 ± 1.2 days. Muscle activity was recorded bilaterally from the thoracic ES. Root mean square (RMS), coordinates of the barycentre, mean frequency (MNF), and entropy were derived from the HDEMG signals. Reliability was determined with intraclass correlation coefficient (ICC), coefficient of variation, and standard error of measurement. RESULTS: Good-to-excellent intra-session reliability was found for all parameters and tasks (ICC: 0.79-0.99), whereas inter-session reliability varied across tasks. Static tasks demonstrated higher reliability in most parameters compared to functional and dynamic tasks. Absolute RMS and MNF showed the highest overall reliability across tasks (ICC: 0.66-0.98), while reliability of the barycentre was influenced by the direction of the movements. CONCLUSION: RMS and MNF derived from HDEMG show consistent inter-session reliability in goal-directed voluntary movements of the trunk and reaching tasks, whereas the measures of the barycentre and entropy demonstrate task-dependent reliability.

Specific versus non-specific exercises for the neck extensor muscles in women with chronic idiopathic neck pain: A randomized controlled trial.

BACKGROUND: Structural and functional impairments of the cervical extensor muscles have been demonstrated in people with neck pain. A global exercise approach targeting all neck extensor muscles has shown positive effects in this population. However, to date, the efficacy of exercises specifically targeting the deep neck extensors has neither been tested nor compared to global exercises for the neck extensors. OBJECTIVES: To compare the effects on pain and disability of a specific lower deep neck extensors (SLDNE) versus a general neck extensor (GNE) exercise program in women with chronic idiopathic neck pain. METHODS: Fourty-three women with chronic idiopathic neck pain were randomly allocated to either a six-week SLDNE or a GNE exercise program. As primary outcome, neck disability was measured with the Neck Disability Index (NDI). Secondarily, pain intensity (VAS), cervical ROM, pressure pain thresholds (PPTs), cervical and thoracic posture and self-perceived benefit of treatment (GROC) were also measured. Every outcome was measured at baseline and immediately after treatment, except NDI, which was also measured at 6-months follow-up. The GROC was only assessed post-intervention. RESULTS: Both exercise programs lead to reduced neck disability immediately post-intervention (within-group mean difference [MD] = -6.09; 95% Confidence Interval [CI]: 7.75, -4.42 and -4.73; 95%CI: 6.57, -2.91 respectively) and at the 6-months follow-up (-4.47; 95%CI: 6.41, -2.53 and -4.74; 95%CI: 6.50, -2.97), but with no between group differences. Similar results were found for pain intensity post-intervention, with no between group interaction (within-group MD = -20.87 mm; 95% CI: 28.55, -13.19 and -18.00 mm; 95%CI: (-26.24, -9.76) for SLDNE and GNE groups, respectively). GROC improved after both interventions without any between-group difference. CONCLUSIONS: A six-week exercise program specifically targeting the lower deep neck extensors lead to comparable outcomes as a general neck extensor exercise program in women with chronic idiopathic neck pain.

Measurement properties of smartphone applications for the measurement of neck range of motion: a systematic review and meta analyses.

BACKGROUND: Smartphone applications offer an accessible and practical option to measure neck range of motion (ROM) and are becoming more commonly used in clinical practice. We assessed the validity, reliability, and responsiveness of smartphone applications (apps) to measure neck ROM in people with and without neck pain. METHODS: A comprehensive electronic search strategy of the main electronic databases was conducted from inception until June 2021. The identified studies investigated apps which measured neck ROM, and evaluated their validity, reliability, or responsiveness, in adult participants with neck pain or asymptomatic individuals. Two independent reviewers determined eligibility and risk of bias following COSMIN guidelines. The quality of evidence was assessed according to the GRADE approach. RESULTS: Eleven studies, with a total of 376 participants were included. Three types of apps were identified: clinometer apps, compass apps, and other apps of 'adequate' to 'doubtful' risk of bias. A meta-analysis revealed 'good' to 'excellent' intra-rater and inter-rater reliability across the three types of apps. The overall validity was rated from 'moderate' to 'very high' across all apps. The level of evidence was rated as 'low' to 'very low'. CONCLUSION: Smartphone applications showed sufficient intra-rater reliability, inter-rater reliability, and validity to measure neck ROM in people with and without neck pain. However, the quality of evidence and the confidence in the findings are low. High-quality research with large sample sizes is needed to further provide evidence to support the measurement properties of smartphone applications for the assessment of neck ROM. STUDY REGISTRATION: Following indications of Prisma-P guidelines, this protocol was registered in PROSPERO on 1/05/2021 with the number CRD42021239501.

Group and individual telehealth for chronic musculoskeletal pain: A scoping review.

BACKGROUND CONTEXT: Musculoskeletal (MSK) pain presents a global challenge. Individual and group pain management programmes (PMPs) are recommended approaches for patients with chronic MSK disorders. With advances in remote healthcare capability, telehealth, and the recent COVID-19 pandemic, the importance of telehealth PMPs has become even more evident. Nevertheless, it is not known how patients perceive PMPs for their MSK complaint when delivered via telehealth. OBJECTIVE: To synthesise the evidence of patients' experiences of group and individual telehealth PMPs for chronic MSK pain. DESIGN: A scoping review informed by the PRISMA extension for scoping reviews. DATA SOURCES: Based on a planned search strategy, modified following initial searches, an electronic search was conducted of key databases: Cochrane Library, Medline, CINAHL, EMBASE, AMED, SportDiscus and APA PsychInfo from 2010 until 11 May 2021. STUDY SELECTION: Any qualitative or mixed methods study reporting patient experiences of telehealth PMPs for patients with MSK disorders. DATA EXTRACTION AND DATA SYNTHESIS: Data were extracted and synthesised using thematic analysis. RESULTS: From 446 identified studies, 10 were included. Just two studies investigated group telehealth PMPs for patients with MSK disorders, with eight delivered individually. Four main themes emerged: (1) Usability of the technology, (2) Tailored care, (3) Therapeutic alliance and (4) Managing behaviour. The findings highlight patient acceptability of telehealth to support self-management for chronic MSK disorders, with appropriate clinical and technical support. Group telehealth has the potential to empower patients with peer support. Remote delivery of PMPs also impacts on how patients and providers interact, communicate and develop a therapeutic relationship. CONCLUSIONS AND IMPLICATIONS: Barriers and enablers to engagement in telehealth PMPs for patients with chronic MSK disorders have been identified. Peer support and group cohesiveness can be achieved remotely to enhance the patient experience. There is a critical need for further research in this area.

Differentiating migraine, cervicogenic headache and asymptomatic individuals based on physical examination findings: a systematic review and meta-analysis.

BACKGROUND: Migraine and cervicogenic headache (CGH) are common headache disorders, although the large overlap of symptoms between them makes differential diagnosis challenging. To strengthen differential diagnosis, physical testing has been used to examine for the presence of musculoskeletal impairments in both conditions. This review aimed to systematically evaluate differences in physical examination findings between people with migraine, CGH and asymptomatic individuals. METHODS: The databases MEDLINE, PubMed, CINAHL, Web of Science, Scopus, EMBASE were searched from inception until January 2020. Risk of bias was assessed with the Downs and Black Scale for non-randomized controlled trials, and with the Quality Assessment of Diagnostic Accuracy Studies tool for diagnostic accuracy studies. When possible, meta-analyses with random effect models was performed. RESULTS: From 19,682 articles, 62 studies were included in this review and 41 were included in the meta-analyses. The results revealed: a) decreased range of motion [°] (ROM) on the flexion-rotation test (FRT) (17.67, 95%CI:13.69,21.65) and reduced neck flexion strength [N] (23.81, 95%CI:8.78,38.85) in CGH compared to migraine; b) compared to controls, migraineurs exhibit reduced flexion ROM [°] (- 2.85, 95%CI:-5.12,-0.58), lateral flexion ROM [°] (- 2.17, 95% CI:-3.75,-0.59) and FRT [°] (- 8.96, 95%CI:-13.22,-4.69), reduced cervical lordosis angle [°] (- 0.89, 95%CI:-1.72,-0.07), reduced pressure pain thresholds over the cranio-cervical region [kg/cm2], reduced neck extension strength [N] (- 11.13, 95%CI:-16.66,-5.6) and increased activity [%] of the trapezius (6.18, 95%CI:2.65,9.71) and anterior scalene muscles (2.87, 95%CI:0.81,4.94) during performance of the cranio-cervical flexion test; c) compared to controls, CGH patients exhibit decreased neck flexion (- 33.70, 95%CI:-47.23,-20.16) and extension (- 55.78, 95%CI:-77.56,-34.00) strength [N]. CONCLUSION: The FRT and neck flexion strength could support the differential diagnosis of CGH from migraine. Several physical tests were found to differentiate both headache types from asymptomatic individuals. Nevertheless, additional high-quality studies are required to corroborate these findings. STUDY REGISTRATION: Following indications of Prisma-P guidelines, this protocol was registered in PROSPERO on 21/05/2019 with the number CRD42019135269 . All amendments performed during the review were registered in PROSPERO, indicating the date and what and why was changed.

Neck pain with radiculopathy: A systematic review of classification systems.

BACKGROUND: Disparities in eligibility criteria for cervical radiculopathy (CR) in clinical trials have been acknowledged previously. The increasing use of CR related neck pain classification systems to inform eligibility criteria in clinical trials warrants evaluation. OBJECTIVE: To evaluate existing neck pain classification systems for CR. DESIGN: Systematic review and critical appraisal, reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. METHODS: Database searches were performed from inception until 31/7/2020. Neck pain classification systems containing CR as a component were included. Methodological quality of each classification system was assessed using seven measurement property domains and scored using a framework developed by Buchbinder and colleagues. Classification criteria for CR from classification systems assessed as moderate or good quality were narratively synthesised using inductive content analysis which consisted of selecting unit of analysis, open coding, grouping and categorisation. RESULTS: Out of 19,975 references, 14,893 remained after elimination of duplicates with 17 articles reporting 11 classification systems included. Five moderate and one good quality classification systems were identified. Nine classification criteria for CR were derived, including dermatomal sensory deficit, positive Spurling's test, positive upper limb tension test. CONCLUSION: All classification systems had methodological limitations with Childs et al. (2008) classification system identified as good quality and most clinically useful. Future studies should investigate the reliability of Childs et al. (2008) classification system as it has the potential to further strengthen its methodological quality and clinical utility. The nine derived classification criteria can inform eligibility criteria in future trials.

Exploring expectations and perceptions of different manual therapy techniques in chronic low back pain: a qualitative study.

BACKGROUND: Chronic low back pain (CLBP) prevalence has steadily increased over the last two decades. Manual therapy (MT) is recommended within a multimodal management approach to improve pain and disability although evidence investigating the patients' experience of MT is scarce. OBJECTIVE: To explore expectations and perceptions of MT techniques in people with CLBP. METHODS: A qualitative study embedded sequential to an experimental trial using semi-structured interviews (SSI) explored participants' experiences of thrust, non-thrust and sham technique. Purposive sampling enabled variance in age and CLBP duration. An evidence informed topic guide was used. Data were analysed using thematic analysis (TA). Respondent validation and peer debriefing enhanced trustworthiness. The Consolidating Criteria for Reporting Qualitative Studies (COREQ) reported methodological rigour. FINDINGS: Ten participants (50% male) with a mean age of 29.1 years (Standard Deviation (SD): 7.9, range: 19-43), a mean pain intensity of 4.5 on a Numeric Rating Scale (NRS) 0-10 (SD: 1.5, range: 2-7), a mean Oswestry Disability Score (ODI) of 9 (SD: 4.6, range: 2-17) and a mean Tampa Scale of Kinesiophobia (TSK) score of 38.6 (SD: 4.8, range: 30-45) participated. Four themes were identified: understanding of pain; forming expectations; perception of care; re-evaluation of body awareness and management. Understanding of CLBP is formed by an individuals' pain perception and exchange with social environment. This, combined with communication with physiotherapist influenced expectations regarding the MT technique. CONCLUSION: Expectations for MT were formed by an individual's social environment and previous experience. A treatment technique is perceived as positive if its characteristics are aligned with the individual's understanding of pain and if care is delivered in an informative and reassuring manner.

Trunk control during repetitive sagittal movements following a real-time tracking task in people with chronic low back pain.

Precision of trunk movement has commonly been examined by testing relocation accuracy rather than evaluating accuracy of tracking dynamic movement. In this study we used a 3-D motion capture system to provide a novel real-time tracking task to assess trunk motor control at varying movement speeds between people with and without chronic non-specific low back pain (LBP). Eleven asymptomatic volunteers and 15 participants with chronic non-specific LBP performed 12 continuous cycles of trunk flexion-extension following real time visual feedback, during which, trunk motion was measured using eight optoelectronic infrared cameras. Significant time differences between the feedback and actual trunk motion were found between groups (P = 0.001). Both groups had similar variability of tracking accuracy when following the feedback (P > 0.05). However, tracking variability at a slow speed correlated (P = 0.03; r = 0.55) with the Fear-Avoidance Beliefs Questionnaire (FABQ) scores in those with LBP. This study shows that both asymptomatic people and individuals with LBP displayed anticipatory behaviour, however, the response of those with LBP was consistently delayed in tracking the visual feedback compared to the asymptomatic group. Additionally, the extent of variability of tracking accuracy over repeated tracking cycles was associated with the degree of fear of movement in people with LBP.

Successful recovery following musculoskeletal trauma: protocol for a qualitative study of patients' and physiotherapists' perceptions.

BACKGROUND: Annually in the UK, 40,000-90,000 people are involved in a traumatic incident. Severity of injury and how well people recover from their injuries varies, with physiotherapy playing a key role in the rehabilitation process. Recovery is evaluated using multiple outcome measures for perceived levels of pain severity and quality of life. It is unclear however, what constitutes a successful recovery from injury throughout the course of recovery from the patient perspective, and whether this aligns with physiotherapists' perspectives. METHODS: A qualitative study using two approaches: Interpretive Phenomenological Analysis (IPA) using semi-structured interviews and thematic analysis following the Kreuger framework for focus groups. A purposive sample of 20 patients who have experienced musculoskeletal trauma within the past 4 weeks and 12 physiotherapists who manage this patient population will be recruited from a single trauma centre in the UK. Semi-structured interviews with patients at 4 weeks, 6 and 12 months following injury, and 2 focus groups with physiotherapists will be undertaken at one time point. Views and perceptions on the definition of recovery and what constitutes a successful recovery will be explored using both methods, with a focus on the lived experience and patient journey following musculoskeletal trauma, and how this changes through the process of recovery. Data from both the semi-structured interviews and focus groups will be analysed separately and then integrated and synthesised into key themes ensuring similarities and differences are identified. Strategies to ensure trustworthiness e.g., reflexivity will be employed. DISCUSSION: Recovery following musculoskeletal trauma is complex and understanding of the concept of successful recovery and how this changes over time following an injury is largely unknown. It is imperative to understand the patient perspective and whether these perceptions align with current views of physiotherapists. A greater understanding of recovery following musculoskeletal trauma has potential to change clinical care, optimise patient centred care and improve efficiency and clinical decision making during rehabilitation. This in turn can contribute to improved clinical effectiveness, patient outcome and patient satisfaction with potential service and economic cost savings. This study has ethical approval (IRAS 287781/REC 20/PR/0712).

Tutorial: Analysis of motor unit discharge characteristics from high-density surface EMG signals.

Recent work demonstrated that it is possible to identify motor unit discharge times from high-density surface EMG (HDEMG) decomposition. Since then, the number of studies that use HDEMG decomposition for motor unit investigations has increased considerably. Although HDEMG decomposition is a semi-automatic process, the analysis and interpretation of the motor unit pulse trains requires a thorough inspection of the output of the decomposition result. Here, we report guidelines to perform an accurate extraction of motor unit discharge times and interpretation of the signals. This tutorial includes a discussion of the differences between the extraction of global EMG signal features versus the identification of motor unit activity for physiological investigations followed by a comprehensive guide on how to acquire, inspect, and decompose HDEMG signals, and robust extraction of motor unit discharge characteristics.

Common disbalance in the brain parenchyma of dementias: Phospholipid profile analysis between CADASIL and sporadic Alzheimer's disease.

Sporadic Alzheimer's disease (SAD) is the most common form of dementia, and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most frequent hereditary ischemic small vessel disease of the brain. Relevant biomarkers or specific metabolic signatures could provide powerful tools to manage these diseases. Therefore, the main goal of this study was to compare the postmortem frontal cortex gray matter, white matter and cerebrospinal fluid (CSF) between a cognitively healthy group and CADASIL and SAD groups. We evaluated 352 individual lipids, belonging to 13 lipid classes/subclasses, using mass spectrometry, and the lipid profiles were subjected to multivariate analysis to discriminate between the dementia groups (CADASIL and SAD) and healthy controls. The main lipid molecular species showing greater discrimination by partial least squares-discriminant analysis (PLS-DA) and a higher significance multivariate correlation (sMC) index were as follows: phosphatidylserine (PS) PS(44:7) and lysophosphatidylethanolamine (LPE) LPE(18:2) in gray matter (GM); phosphatidylethanolamine (PE) PE(32:2) and phosphatidylcholine PC PC(44:6) in white matter (WM), and ether PE (ePE) ePE(38:2) and ether PC (ePC) ePC(34:3) in CSF. Common phospholipid molecular species were obtained in both dementias, such as PS(44:7) and lyso PC (LPC) LPC(22:5) in GM, PE(32:2) in WM and phosphatidic acid (PA) PA(38:5) and PC(42:7) in CFS. Our exploratory study suggests that phospholipids (PLs) involved in neurotransmission alteration, connectivity impairment and inflammation response in GM, WM and CSF are a transversal phenomenon affecting dementias such as CADASIL and SAD independent of the etiopathogenesis, thus providing a possible common prodromal phospholipidic biomarker of dementia.

Non-traumatic chronic shoulder pain is not associated with changes in rotator cuff interval tendon thickness.

OBJECTIVE: To determine whether the thickness of the rotator interval tendons is different when comparing both symptomatic and non-symptomatic sides in people with chronic shoulder pain, and to those free of pain. Furthermore, to calculate the level of association between the rotator interval tendon thicknesses and perceived shoulder pain-function. DESIGN: A cross-sectional, observational study. METHOD: The supraspinatus, subscapularis and biceps brachii tendon thickness of sixty two patients with chronic shoulder pain were determined from standardized ultrasonography measures performed on both shoulders, whereas only the dominant arm was measured for the control subjects. FINDINGS: Supraspinatus, subscapularis and biceps brachii tendon thickness was comparable between sides in the symptomatic group and was also comparable between the symptomatic and asymptomatic participants. In addition, the correlation between the tendon thickness and shoulder pain-function was non-significant. INTERPRETATIONS: Tendon thickness was unaltered in people with chronic shoulder pain. These findings do not rule out the possibility that other changes in the tendon are present such as changes in the elastic properties and cell population and this should be explored in future studies.

Alterations in jaw clenching force control in people with myogenic temporomandibular disorders.

Isometric bite force control, via measures of force accuracy, force steadiness and force proprioception, was assessed in patients with myogenic temporomandibular disorders (TMDs) compared to healthy controls. Twelve people with myogenic TMDs and twelve age- and gender-matched asymptomatic controls performed maximal voluntary contractions (MVC) of unilateral jaw clenching followed by submaximal isometric contractions, with and without visual feedback of force, at 10, 30 50% and 70% MVC. Force performance was assessed with indices of accuracy (mean distance, MD) and precision (standard deviation, SD) and reported as a percentage of the MVC. A mixed-effect model was used to evaluate differences in MVC, MD and SD. The MVC was lower in the TMD group when clenching either ipsilateral or contralateral to the side of greatest pain (p < 0.05). No difference in MD was observed between groups. The SD depended on the interaction between group and painful side (p = 0.04) with the TMD group displaying higher SD when executing the task with the most painful side when compared to the ipsilateral or contralateral sides of the control group. The reduced maximal bite force and force steadiness observed in people with myogenic pain may interfere with masticatory function and should be considered when planning therapeutic interventions for TMDs.

Relieving phantom limb pain with multimodal sensory-motor training.

OBJECTIVE: The causes for the disabling condition of phantom limb pain (PLP), affecting 85% of amputees, are so far unknown, with few effective treatments available. Sensory feedback based strategies to normalize the motor commands to control the phantom limb offer important targets for new effective treatments as the correlation between phantom limb motor control and sensory feedback from the motor intention has been identified as a possible mechanism for PLP development. APPROACH: Ten upper-limb amputees, suffering from chronic PLP, underwent 16 days of intensive training on phantom-limb movement control. Visual and tactile feedback, driven by muscular activity at the stump, was provided with the aim of reducing PLP intensity. MAIN RESULTS: A 32.1% reduction of PLP intensity was obtained at the follow-up (6 weeks after the end of the training, with an initial 21.6% reduction immediately at the end of the training) reaching clinical effectiveness for chronic pain reduction. Multimodal sensory-motor training on phantom-limb movements with visual and tactile feedback is a new method for PLP reduction. SIGNIFICANCE: The study results revealed a substantial reduction in phantom limb pain intensity, obtained with a new training protocol focused on improving phantom limb motor output using visual and tactile feedback from the stump muscular activity executed to move the phantom limb.