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| 2. |
- Elcadi, Guilherme H.
(författare)
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Near infrared spectroscopy for assessing oxygenation and hemodynamics in the upper extremities of healthy subjects and patients with work-related muscle pain
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The prevalence of work-related muscle pain (WRMP) is large in the general population in the industrialized world. Despite significant advances over recent years in some research areas, the mechanisms of why WRMP occurs and the pathophysiological mechanisms behind the disorders are still unclear. One suggested explanation is that WRMP is caused initially by a limitation of the local muscle circulation and oxidative metabolism. There is a lack of objective methods to gauge the development and diagnosis of WRMP. Near infrared spectroscopy (NIRS) is a non-invasive technique that allows for determinations of oxygenation and blood flow. The purpose of this thesis was to evaluate NIRS (1) as a method for measuring muscle oxygenation and hemodynamics for the extensor carpi radialis (ECR) and trapezius descendens muscles (TD), and (2) to investigate whether variables measured by NIRS differed between patients diagnosed with WRMP and healthy subjects. Several variables of NIRS were produced and investigated. These included muscle oxygenation (StO2%), changes during contractions (∆StO2%) and StO2% recovery (Rslope), total hemoglobin (HbT) as an indication of blood volume and its changes during contractions (∆HbT). In addition, for the ECR, by applying an upper arm venous occlusion (VO) HbTslope increase as a surrogate of blood flow, and for both VO and arterial occlusion (AO) HHbslope increase (i.e. deoxyhemoglobin slope) as a surrogate of oxygen consumption were variables of interest. A first objective was to determine how StO2% and HbT responded to various contraction forces and how it related to muscle activation measured by electromyography (EMG). For both muscles isometric contractions of 10, 30, 50 and 70% of maximal voluntary contraction (MVC) were maintained for 20 s each by healthy males and females; additionally a 10% MVC contraction was sustained for 5 min. For the different contraction levels, predictable relationships were seen between ∆StO2% and force, and between ∆StO2% and EMG RMS amplitude. The general trend was a decrease in ∆StO2% with increasing force and increasing EMG. Females showed a tendency for a higher oxygen use (i.e., drop in StO2%) for the ECR over force levels than males and a higher RMS% MVC for the TD. For the 10% MVC contraction sustained for 5 min gender specific changes over time for HbT and RMS for the ECR, and for StO2% for the TD muscle were seen. A second objective was to determine the day-to-day reliability of NIRS variables for the ECR and TD muscles at group level (Pooled data) and at gender level (males and females). Measurements were performed on two occasions separated by 4-6 days and intraclass correlation coefficients (ICC) and limits of agreement (LOA) were determined as reliability and reproducibility indicators, respectively. Variables tested were ∆StO2% during submaximal isometric contractions of 10, 30, 50 and 70% MVC and StO2% recovery (Rslope) after contractions and after AO. For the ECR, HbTslope as an indication of blood flow (using VO) and HHbslope as a surrogate of oxygen consumption for both VO and AO were computed. For ∆StO2% for the ECR the highest ICC was at 30% MVC for both the pooled data and at gender level. For the TD ICCs were comparably high for 30, 50, 70 % MVC (for both muscles the ∆StO2% at 10% MVC showed the lowest ICC). Further, females showed a higher ICC than males for contraction levels of 50 and 70% MVC. For both muscles, LOA for ∆StO2% was lowest at 10% and highest at 50 and 70% MVC. For the ECR Rslope ICCs were high for all contraction levels, but was lower for AO; LOA was lowest at 70% MVC. For the TD, Rslope ICCs were also high for all contraction levels and LOA was lowest at 30 % MVC. ICC for HbTslope was the lowest of all variables tested. For HHbslope ICC was higher for AO than for VO, and LOA was lower for AO. A third objective was to determine if there were differences between healthy subjects and patients diagnosed with WRMP in ∆StO2% and ∆HbT responses during varying submaximal contractions (10, 30, 50 and 70% MVC), and StO2% recovery (Rslope) immediately after contractions and AO. Additional variables tested in the ECR at rest were HHbslope to indicate oxygen consumption (using AO) and HbTslope as an indication of blood flow. There were no differences between groups in ∆StO2% and ∆HbT variables during the contractions or Rslope in the recovery after contractions or AO. Furthermore, HbTslope was not different between groups However, oxygen consumption for the ECR and StO2% for the TD at rest were significantly greater for healthy subjects compared to patients. A fourth objective was to determine if there were differences in StO2% and HbT between healthy subjects and WRMP patients during a 12 min sustained contraction of 15 % MVC. In addition, the protocol included a recovery period of 30 min. Prior to contraction, as well as during the recovery period, HbTslope as a surrogate of blood flow was determined for the ECR. Neither the ECR nor the TD exhibited significant differences between groups for StO2% and HbT during the contraction. For the TD patients showed a lower StO2% value at rest and throughout the contraction than healthy subjects. For the ECR HbT during the sustained contraction the general trend was an initial decrease with gradual increase throughout the contraction for both groups. For HbTslope no differences were seen between patients and healthy subjects before the sustained contraction and during the recovery period for both muscles.NIRS is deemed a suitable technique for assessing physiological measurements of the upper extremity, including for day-to-day testing.NIRS was not able to distinguish between the patients with WRMP and controls. A concern in the thesis is the characteristics of the patient group in being equally active in recreational sports, actively working, and similar in muscle strength as controls. Thus, applying NIRS for studying a more severe patient group could yield different results.
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- Elcadi, Guilherme H., 1966-, et al.
(författare)
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Shoulder and forearm oxygenation and myoelectric activity in patients with work related muscle pain and healthy subjects
- 2013
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Ingår i: European Journal of Applied Physiology. - New York : Springer. - 1439-6319 .- 1439-6327. ; 113:5, s. 1103-1115
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Tidskriftsartikel (refereegranskat)abstract
- We tested hypotheses of (i) reduced oxygen usage, oxygen recovery, blood flow and oxygen consumption; and (ii) increased muscle activity for patients diagnosed with work related muscle pain in comparison to healthy controls. Oxygenation was measured with near infrared spectroscopy (NIRS), and muscle activity with EMG for the extensor carpi radialis (ECR) and trapezius descendens (TD) muscles. Eighteen patients with diffuse neck-shoulder-arm pain and seventeen controls (matched in age and sex) were equipped with NIRS and EMG probes. After determining an individual’s maximum voluntary contraction (MVC) force, short term (20 sec) isometric contractions for the ECR and TD of 10%, 30%, 50% and 70% MVC generated ∆StO2% and StO2% recovery (Rslope) from NIRS, and RMS%max from EMG signals. In addition, upper arm venous (VO) and arterial (AO) occlusions generated slopes of total hemoglobin (HbTslope) and deoxyhemoglobin (HHbslope) for the resting ECR as surrogates of blood flow and oxygen consumption, respectively. Mixed Model analyses, t-tests, and Mann-Whitney test were used to assess differences between groups. There was no significant difference in MVC between groups for either muscle. Also, ∆StO2%, Rslope for either muscle, and ECR-HbTslope were not different between groups, thus our hypotheses of reduced oxygen use, recovery, and blood flow for patients were not confirmed. However, patients had a significantly lower ECR-HHbslope confirming our hypothesis of reduced consumption. Further, there was no difference in RMS%max during contractions meaning that the hypothesis of increased activity for patients was not confirmed. When taking into account the number of NIRS variables studied, differences we found between our patient group and healthy controls (i.e. in forearm oxygen consumption and shoulder oxygen saturation level) may be considered modest. Overall our findings may have been impacted by the fact that our patients and controls were similar in muscle strength, which is in contrast to previous studies.
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| 5. |
- Flodgren, Gerd, 1961-, et al.
(författare)
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Changes in interstitial noradrenaline, trapezius muscle activity and oxygen saturation during low-load work and recovery
- 2009
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 107:1, s. 31-42
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Tidskriftsartikel (refereegranskat)abstract
- Both physical as well as mental demands result in an increased activity in the sympathetic nervous system (SNS) with changes in blood-pressure and heart-rate. Through local release of catecholamines, e.g. noradrenaline (NAd) SNS exerts various actions at the muscle level. The aims of this study were to investigate the effects of low-load repetitive work alone and in combination with mental demands on local muscle interstitial noradrenaline concentration [NAd]i, muscle activity and oxygenation, assessed with microdialysis, surface electromyography, and near-infrared spectroscopy, respectively. Healthy females (n = 15) were exposed to (1) 30 min repetitive work (RW) and (2) 30 min repetitive work with superimposed mental load (RWML) on two different occasions. Muscle [NAd]i and muscle activity increased significantly in response to RW, but did not increase further during RWML. For RW, [NAd]i was found to be inversely correlated to muscle activity. Oxygenation decreased significantly during work, independently of occasion. Our findings indicate that low-load work causes significantly increased trapezius muscle [NAd]i in healthy females, and short periods of superimposed mental load do not add to this increase and further, that both muscle activity and oxygenation were unaffected by the superimposed mental load.
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| 6. |
- Flodgren, Gerd, et al.
(författare)
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Combining microdialysis and near infrared spectroscopy for studying effects of low-load repetitive work on the intramuscular chemistry in trapezius myalgia
- 2010
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Ingår i: Journal of Biomedicine and Biotechnology. - : Hindawi Limited. - 1110-7243 .- 1110-7251. ; 2010
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological research provides strong evidence for a link between repetitive work (RW) and the development of chronic trapezius myalgia (TM). The aims were to further elucidate if an accumulation of sensitising substances or impaired oxygenation is evident in painful muscles during RW. Females with TM (n=14) were studied during rest, 30 min RW and 60 min recovery. Microdialysate samples were obtained to determine changes in [glutamate], [PGE2], [lactate], and [pyruvate] relative to work. Muscle oxygenation (%StO2) was assessed using near-infrared spectroscopy. During work all investigated substances, except PGE2, increased significantly: [glutamate] (54%, P<0.0001), [lactate] (26%, P<0.005), [pyruvate] (19%, P<0.0001), while the %StO2 decreased (P<0.05). During recovery [PGE2] decreased (P<0.005), [lactate] remained increased (P<0.001), [pyruvate] increased progressively (P<0.0001), and %StO2 had returned to baseline. Changes in substance concentrations and oxygenation in response to work indicate normal increase in metabolism but no ongoing inflammation in subjects withTM.
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| 9. |
- Wiitavaara, Birgitta, et al.
(författare)
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Prevalence, diagnostics, and management of musculoskeletal disorders in primary health care in Sweden : an investigation of 2000 randomly selected patient records
- 2017
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Ingår i: Journal of Evaluation In Clinical Practice. - : Wiley. - 1356-1294 .- 1365-2753. ; 23:2, s. 325-332
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Tidskriftsartikel (refereegranskat)abstract
- Background. To improve the care of patients suffering from musculoskeletal disorders (MSD) further knowledge regarding the prevalence, diagnostics and management of different MSD in primary care is required. Thus the aims of this study were: -to investigate the prevalence of patients seeking care due to different MSD at primary health care centres (PHCs); -to chart different factors as symptoms, diagnosis, and actions prescribed for patients that visited the PHCs due to MSD; and -to make comparisons regarding differences due to gender, age, and rural or urban PHC.Methods. 2000 patient records for patients in working age were randomly selected equally distributed on one rural and one urban PHC. A 3-year period was reviewed retrospectively. For all patient records age, sex, occupation, occupational activity, date of visit, if it was a new or re-visit, cause to the visit, and diagnosis related to the visit were registered. For visits due to MSD the location of the patients symptoms, which symptoms were described in the patient record, the type of those symptoms, which actions were prescribed to resolve the patients problems, and also sickleave prior to and after the visit, were registered. Data was analysed using cross tabulation, multidimensional Chi-square (Pearson), and a probability level of p < .05.Results. The prevalence of MSD was high, almost 60 % of the patients had some sort of MSD symptoms, either at the day for visit or the reviewed 3 year period, and a bit higher among women than men. Upper and lower limb problems were most common. Symptoms were most prevalent in the young and middle age-groups. The patients got a variety of different diagnoses, and between 13-35 % of the patients did not receive a MSD-diagnose despite having MSD-symptoms. There was a great variation in how the cases were handled. Medication and sick leave certificates were most common while work-related rehabilitation was less common. Conclusion. The present study points out some weaknesses regarding diagnostics and management of MSD in primary care. Further studies to compare the results regarding diagnoses for musculoskeletal symptoms and measures taken to solve the patients’ problems would be of interest.
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