10 results on '"Martin Björk"'
Search Results
2. The impact of visuospatial and executive function on activity performance and outcome after robotic or conventional gait training, long-term after stroke—as part of a randomized controlled trial
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Maria Bergqvist, Marika C Möller, Martin Björklund, Jörgen Borg, and Susanne Palmcrantz
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Medicine ,Science - Abstract
Introduction Visuospatial and executive impairments have been associated with poor activity performance sub-acute after stroke. Potential associations long-term and in relation to outcome of rehabilitation interventions need further exploration. Aims To explore associations between visuospatial and executive function and 1) activity performance (mobility, self-care and domestic life) and 2) outcome after 6 weeks of conventional gait training and/or robotic gait training, long term (1–10 years) after stroke. Methods Participants (n = 45), living with stroke affecting walking ability and who could perform the items assessing visuospatial/executive function included in the Montreal Cognitive Assessment (MoCA Vis/Ex) were included as part of a randomized controlled trial. Executive function was evaluated using ratings by significant others according to the Dysexecutive Questionnaire (DEX); activity performance using 6-minute walk test (6MWT), 10-meter walk test (10MWT), Berg balance scale, Functional Ambulation Categories, Barthel Index and Stroke Impact Scale. Results MoCA Vis/Ex was significantly associated with baseline activity performance, long-term after stroke (r = .34-.69, p < .05). In the conventional gait training group, MoCA Vis/Ex explained 34% of the variance in 6MWT after the six-week intervention (p = 0.017) and 31% (p = 0.032) at the 6 month follow up, which indicate that a higher MoCA Vis/Ex score enhanced the improvement. The robotic gait training group presented no significant associations between MoCA Vis/Ex and 6MWT indicating that visuospatial/executive function did not affect outcome. Rated executive function (DEX) presented no significant associations to activity performance or outcome after gait training. Conclusion Visuospatial/executive function may significantly affect activity performance and the outcome of rehabilitation interventions for impaired mobility long-term after stroke and should be considered in the planning of such interventions. Patients with severely impaired visuospatial/executive function may benefit from robotic gait training since improvement was seen irrespective of visuospatial/executive function. These results may guide future larger studies on interventions targeting long-term walking ability and activity performance. Trial registration clinicaltrials.gov (NCT02545088) August 24, 2015.
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- 2023
3. Development, Test and Flight of the SMART-1 Attitude and Orbit Control System
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Peter Rathsman, Sten Berge, Martin Björk, Per Bodin, Anders Edfors, and Joakim Kugelberg
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Engineering ,Software ,Spacecraft ,business.industry ,Hardware-in-the-loop simulation ,Trajectory ,Orbit (dynamics) ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Code generation ,Propulsion ,business ,Lunar orbit ,Simulation - Abstract
*This paper presents results from the development, test and flight of the SMART-1 Attitude and Orbit Control System (AOCS). SMART-1 was captured in lunar orbit on November 16, 2004 after more than one year of travel around the earth since its launch on September 27, 2003. The arrival to the moon marks the completion of the primary mission objective which is to demonstrate the use of Electric Primary Propulsion in a low-thrust transfer trajectory. The arrival to the moon also marked the start of the lunar science observation phase. The Swedish Space Corporation is the prime contractor for the SMART-1 spacecraft. The paper explains how the SMART-1 AOCS was developed and tested. The AOCS flight software was produced using automatic code generation. The use of automatic code generation has proven to be an efficient development approach in which accurate code models have been available throughout the development cycle of the software. The code has been developed starting from early analysis models. These models were integrated into one single AOCS subsystem model which was split up into one simulator part and one flight software part. The simulator part was delivered to the real-time spacecraft system simulator while the flight software part was integrated into the over-all on-board software. All the way through this development, it has been possible to simulate the AOCS subsystem in a MATLAB/Simulink environment using the very parts from which code was generated for the system simulator as well as the on-board software. The availability of these accurate code models has been useful for development of tests on unit and system level involving different degrees of hardware in the loop. The paper explains how the software was developed and how it was used in these different levels of testing. The paper also explains how the accurate code models have been used for analysis of in-flight performance.
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- 2005
4. The SMART-1 Attitude and Orbit Control System: Flight Results from the First Mission Phase
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Anders Edfors, Per Bodin, Joakim Kugelberg, Martin Björk, Sten Berge, Helmut Meier, Ton van Overbeek, Peter Rathsman, Giuseppe D. Racca, and Luca Stagnaro
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Computer science ,business.industry ,Orbit Attitude and Maneuvering System ,Control system ,Phase (waves) ,Orbit (control theory) ,Aerospace engineering ,Graveyard orbit ,Orbit insertion ,business - Published
- 2004
5. Unequal physical activity among children with cerebral palsy in Sweden—A national registry study
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Frida Degerstedt, Martin Björklund, Britt‐Inger Keisu, and Birgit Enberg
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inequality ,leisure ,norms ,physical education ,youth ,Medicine - Abstract
Abstract Aim To examine the extent to which sex, country of birth, and functional aspects influence participation in physical education and physical leisure activity among children with cerebral palsy (CP) in Sweden. Methods This national cross‐sectional registry study included children with CP aged 6 to 18 years who participated in the Swedish national quality registry, the Cerebral Palsy Follow‐up Program, CPUP, in 2015. Comparisons and associations between sex, country of birth, and functional aspects and physical leisure/physical education were examined using chi‐squared and multivariable logistic regression analysis. Results The study included 1935 children. Of them, 1625 (87%) reported participating in physical education and 989 (53%) reported participating in physical leisure activity. Children born in Sweden had higher odds of participating in physical education (OR: 1.99; 95% CI: 1.20‐3.28) and physical leisure activity (OR: 2.51; 95% CI: 1.70‐3.72) compared with children born outside Europe. Greater impairment of gross motor function was associated with lower participation levels. Boys participated slightly more frequently in leisure activities than girls. Conclusion Enhancing social inclusion with regard to disability, birth country, and sex are important and achievable goals for policymakers and practitioners for promoting participation in physical activity for children and adolescents with CP.
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- 2021
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6. Effects of neuromuscular training on knee proprioception in individuals with anterior cruciate ligament injury: a systematic review and GRADE evidence synthesis
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Ashokan Arumugam, Charlotte K Häger, Martin Björklund, and Sanna Mikko
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Medicine - Abstract
Objective To systematically review and summarise the evidence for the effects of neuromuscular training compared with any other therapy (conventional training/sham) on knee proprioception following anterior cruciate ligament (ACL) injury.Design Systematic Review.Data sources PubMed, CINAHL, SPORTDiscus, AMED, Scopus and Physical Education Index were searched from inception to February 2020.Eligibility criteria Randomised controlled trials (RCTs) and controlled clinical trials investigating the effects of neuromuscular training on knee-specific proprioception tests following a unilateral ACL injury were included.Data extraction and synthesis Two reviewers independently screened and extracted data and assessed risk of bias of the eligible studies using the Cochrane risk of bias 2 tool. Overall certainty in evidence was determined using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tool.Results Of 2706 articles retrieved, only 9 RCTs, comprising 327 individuals with an ACL reconstruction (ACLR), met the inclusion criteria. Neuromuscular training interventions varied across studies: whole body vibration therapy, Nintendo-Wii-Fit training, balance training, sport-specific exercises, backward walking, etc. Outcome measures included joint position sense (JPS; n=7), thresholds to detect passive motion (TTDPM; n=3) or quadriceps force control (QFC; n=1). Overall, between-group mean differences indicated inconsistent findings with an increase or decrease of errors associated with JPS by ≤2°, TTDPM by ≤1.5° and QFC by ≤6 Nm in the ACLR knee following neuromuscular training. Owing to serious concerns with three or more GRADE domains (risk of bias, inconsistency, indirectness or imprecision associated with the findings) for each outcome of interest across studies, the certainty of evidence was very low.Conclusions The heterogeneity of interventions, methodological limitations, inconsistency of effects (on JPS/TTDPM/QFC) preclude recommendation of one optimal neuromuscular training intervention for improving proprioception following ACL injury in clinical practice. There is a need for methodologically robust RCTs with homogenous populations with ACL injury (managed conservatively or with reconstruction), novel/well-designed neuromuscular training and valid proprioception assessments, which also seem to be lacking.PROSPERO registration number CRD42018107349.
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- 2021
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7. Systematic review of quantitative imaging biomarkers for neck and shoulder musculoskeletal disorders
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Judith E. Gold, David M. Hallman, Fredrik Hellström, Martin Björklund, Albert G. Crenshaw, Svend Erik Mathiassen, Mary F. Barbe, and Sayed Ali
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MRI ,MSD ,Near-infrared spectroscopy ,Pain ,Ultrasound ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Abstract Background This study systematically summarizes quantitative imaging biomarker research in non-traumatic neck and shoulder musculoskeletal disorders (MSDs). There were two research questions: 1) Are there quantitative imaging biomarkers associated with the presence of neck and shoulder MSDs?, 2) Are there quantitative imaging biomarkers associated with the severity of neck and shoulder MSDs? Methods PubMed and SCOPUS were used for the literature search. One hundred and twenty-five studies met primary inclusion criteria. Data were extracted from 49 sufficient quality studies. Results Most of the 125 studies were cross-sectional and utilized convenience samples of patients as both cases and controls. Only half controlled for potential confounders via exclusion or in the analysis. Approximately one-third reported response rates. In sufficient quality articles, 82% demonstrated at least one statistically significant association between the MSD(s) and biomarker(s) studied. The literature synthesis suggested that neck muscle size may be decreased in neck pain, and trapezius myalgia and neck/shoulder pain may be associated with reduced vascularity in the trapezius and reduced trapezius oxygen saturation at rest and in response to upper extremity tasks. Reduced vascularity in the supraspinatus tendon may also be a feature in rotator cuff tears. Five of eight studies showed an association between a quantitative imaging marker and MSD severity. Conclusions Although research on quantitative imaging biomarkers is still in a nascent stage, some MSD biomarkers were identified. There are limitations in the articles examined, including possible selection bias and inattention to potentially confounding factors. Recommendations for future studies are provided.
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- 2017
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8. Systematic review of biochemical biomarkers for neck and upper-extremity musculoskeletal disorders
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Judith E Gold, David M Hallman, Fredrik Hellström, Martin Björklund, Albert G Crenshaw, Mats Djupsjobacka, Marina Heiden, Svend Erik Mathiassen, George Piligian, and Mary F Barbe
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neck ,lipids ,systematic review ,upper-extremity ,triglycerides ,serotonin ,upper-extremity musculoskeletal disorder ,tendon injury ,muscle injury ,collagen repair ,collagen degradation ,biochemical biomarker ,musculoskeletal disorder ,muscle metabolite ,inflammation ,biomarker ,pain ,Public aspects of medicine ,RA1-1270 - Abstract
OBJECTIVE: This study systematically summarizes biochemical biomarker research in non-traumatic musculoskeletal disorders (MSD). Two research questions guided the review: (i) Are there biochemical markers associated with neck and upper-extremity MSD? and (ii) Are there biochemical markers associated with the severity of neck and upper-extremity MSD? METHODS: A literature search was conducted in PubMed and SCOPUS, and 87 studies met primary inclusion criteria. Following a quality screen, data were extracted from 44 articles of sufficient quality. RESULTS: Most of the 87 studies were cross-sectional and utilized convenience samples of patients as both cases and controls. A response rate was explicitly stated in only 11 (13%) studies. Less than half of the studies controlled for potential confounding through restriction or in the analysis. Most sufficient-quality studies were conducted in older populations (mean age in one or more analysis group >50 years). In sufficient-quality articles, 82% demonstrated at least one statistically significant association between the MSD and biomarker(s) studied. Evidence suggested that: (i) the collagen-repair marker TIMP-1 is decreased in fibro proliferative disorders, (ii) 5-HT (serotonin) is increased in trapezius myalgia, and (iii) triglycerides are increased in a variety of MSD. Only 5 studies showed an association between a biochemical marker and MSD severity. CONCLUSION: While some MSD biomarkers were identified, limitations in the articles examined included possible selection bias, confounding, spectrum effect (potentially heterogeneous biomarker associations in populations according to symptom severity or duration), and insufficient attention to comorbid conditions. A list of recommendations for future studies is provided.
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- 2016
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9. Direction-Specific Impairments in Cervical Range of Motion in Women with Chronic Neck Pain: Influence of Head Posture and Gravitationally Induced Torque.
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Thomas Rudolfsson, Martin Björklund, Åsa Svedmark, Divya Srinivasan, and Mats Djupsjöbacka
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Medicine ,Science - Abstract
Cervical range of motion (ROM) is commonly assessed in clinical practice and research. In a previous study we decomposed active cervical sagittal ROM into contributions from lower and upper levels of the cervical spine and found level- and direction-specific impairments in women with chronic non-specific neck pain. The present study aimed to validate these results and investigate if the specific impairments can be explained by the neutral posture (defining zero flexion/extension) or a movement strategy to avoid large gravitationally induced torques on the cervical spine.Kinematics of the head and thorax was assessed in sitting during maximal sagittal cervical flexion/extension (high torque condition) and maximal protraction (low torque condition) in 120 women with chronic non-specific neck pain and 40 controls. We derived the lower and upper cervical angles, and the head centre of mass (HCM), from a 3-segment kinematic model. Neutral head posture was assessed using a standardized procedure.Previous findings of level- and direction-specific impairments in neck pain were confirmed. Neutral head posture was equal between groups and did not explain the direction-specific impairments. The relative magnitude of group difference in HCM migration did not differ between high and low torques conditions, lending no support for our hypothesis that impairments in sagittal ROM are due to torque avoidance behaviour.The direction- and level-specific impairments in cervical sagittal ROM can be generalised to the population of women with non-specific neck pain. Further research is necessary to clarify if torque avoidance behaviour can explain the impairments.
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- 2017
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10. Affect-focused psychodynamic psychotherapy for depression and anxiety through the Internet: a randomized controlled trial
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Robert Johansson, Martin Björklund, Christoffer Hornborg, Stina Karlsson, Hugo Hesser, Brjánn Ljótsson, Andréas Rousseau, Ronald J. Frederick, and Gerhard Andersson
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Depression ,Anxiety ,Psychotherapy ,Psychodynamic therapy ,Internet ,Affect ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Background. Psychodynamic psychotherapy is a psychological treatment approach that has a growing empirical base. Research has indicated an association between therapist-facilitated affective experience and outcome in psychodynamic therapy. Affect-phobia therapy (APT), as outlined by McCullough et al., is a psychodynamic treatment that emphasizes a strong focus on expression and experience of affect. This model has neither been evaluated for depression nor anxiety disorders in a randomized controlled trial. While Internet-delivered psychodynamic treatments for depression and generalized anxiety disorder exist, they have not been based on APT. The aim of this randomized controlled trial was to investigate the efficacy of an Internet-based, psychodynamic, guided self-help treatment based on APT for depression and anxiety disorders.Methods. One hundred participants with diagnoses of mood and anxiety disorders participated in a randomized (1:1 ratio) controlled trial of an active group versus a control condition. The treatment group received a 10-week, psychodynamic, guided self-help treatment based on APT that was delivered through the Internet. The treatment consisted of eight text-based treatment modules and included therapist contact (9.5 min per client and week, on average) in a secure online environment. Participants in the control group also received online therapist support and clinical monitoring of symptoms, but received no treatment modules. Outcome measures were the 9-item Patient Health Questionnaire Depression Scale (PHQ-9) and the 7-item Generalized Anxiety Disorder Scale (GAD-7). Process measures were also included. All measures were administered weekly during the treatment period and at a 7-month follow-up.Results. Mixed models analyses using the full intention-to-treat sample revealed significant interaction effects of group and time on all outcome measures, when comparing treatment to the control group. A large between-group effect size of Cohen’s d = 0.77 (95% CI: 0.37–1.18) was found on the PHQ-9 and a moderately large between-group effect size d = 0.48 (95% CI: 0.08–0.87) was found on the GAD-7. The number of patients who recovered (had no diagnoses of depression and anxiety, and had less than 10 on both the PHQ-9 and the GAD-7) were at post-treatment 52% in the treatment group and 24% in the control group. This difference was significant, χ2(N = 100, d f = 1) = 8.3, p < .01. From post-treatment to follow-up, treatment gains were maintained on the PHQ-9, and significant improvements were seen on the GAD-7.Conclusion. This study provides initial support for the efficacy of Internet-delivered psychodynamic therapy based on the affect-phobia model in the treatment of depression and anxiety disorders. The results support the conclusion that psychodynamic treatment approaches may be transferred to the guided self-help format and delivered via the Internet.
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- 2013
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