| 11. |
- Ertzgaard, Per, et al.
(författare)
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A new way of assessing arm function in activity using kinematic Exposure Variation Analysis and portable inertial sensors - A validity study
- 2016
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Ingår i: Manual Therapy. - : Elsevier BV. - 1356-689X .- 1532-2769. ; 21, s. 241-249
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Tidskriftsartikel (refereegranskat)abstract
- Portable motion systems based on inertial motion sensors are promising methods, with the advantage compared to optoelectronic cameras of not being confined to a laboratory setting. A challenge is to develop relevant outcome measures for clinical use. The aim of this study was to characterize elbow and shoulder motion during functional tasks, using portable motion sensors and a modified Exposure Variation Analysis (EVA) and evaluate system accuracy with optoelectronic cameras. Ten healthy volunteers and one participant with sequel after stroke performed standardised functional arm tasks. Motion was registered simultaneously with a custom developed motion sensor system, including gyroscopes and accelerometers, and an optoelectronic camera system. The EVA was applied on elbow and shoulder joints, and angular and angular velocity EVA plots was calculated. The EVA showed characteristic patterns for each arm task in the healthy controls and a distinct difference between the affected and unaffected arm in the participant with sequel after stroke. The accuracy of the portable system was high with a systematic error ranging between -1.2 degrees and 2.0 degrees. The error was direction specific due to a drift component along the gravity vector. Portable motion sensor systems have high potential as clinical tools for evaluation of arm function. EVA effectively illustrates joint angle and joint angle velocity patterns that may capture deficiencies in arm function and movement quality. Next step will be to manage system drift by including magnetometers, to further develop clinically relevant outcome variables and apply this for relevant patient groups.
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| 12. |
- Ertzgaard, Per, 1958-
(författare)
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Studies on Spasticity from an Interventional Perspective
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on interventional aspects of spasticity, but has a very holistic approach, grounded in the specialty of Rehabilitation medicine. This means capturing the effects of spasticity, on such a complex biological system as the human being, living in a psychosocial context affecting the situation. When evaluating spasticity there are a number of levels of evidence. The first of course, understanding what we mean with spasticity, where there unfortunately is no consensus. The second level is to study if our treatments affect spasticity in a positive direction. The third is to grasp if a decrease in spasticity improve or normalize patient’s movement patterns. The fourth level investigates if improvement in movement patterns improve patient’s ability to perform activities; and the fifth level, comprising whether this intervention improves life satisfaction. Finally, on a societal level, we wish to investigate whether the improvement in life satisfaction or health related quality of life would motivate society to fund the intervention.Paper I on Goal Attainment Scaling pointed out necessary aspects to consider when using this instrument. This relates, among other things, to the need of learning (“the art of”) goal setting and deciding the purpose of the measurements. Research and clinical use puts different demands on the instrument, for the latter time-efficiency and simplicity to use being most important. For research, it is important to be able to register deterioration, and this can be achieved using the 6-step version.In paper II, concerning validation of the portable motion system, we showed this system to be valid for short-term measurements and that the use of Exposure Variation Analysis (EVA) seems to be a valuable tool for graphically elucidating different movements. The equipment needs further development in handling long-term measurements (which is effectuated), and norms for normal movements in different activities has to be produced. The discriminative value of EVA needs confirmation in coming studies. For the future, there is the intriguing possibility of long-term measurements in patients’ every-day life, thereby getting objective measures on how our patients use their abilities, thus capturing the difference between what you can do and what you actually do.The results from paper III demonstrated a large inequality in Sweden regarding the accessibility of BoNT-A treatment for spasticity. We could also show that treatment with BoNT-A is sound from a health-economic perspective, accounting for the uncertainty of data via the sensitivity analysis. For the future, we need to explore if this inequality also exists for other modes of spasticity treatments, e.g. multidisciplinary spasticity treatment and ITB pumps, and in other countries.In paper IV evaluating multifocal TES, the results could not confirm efficacy with the treatment according to the protocol of the manufacturer. The results have to be interpreted with care, as low compliance and frequent adverse events made deduction not captured in the RCT study. Further studies are needed in a number of areas, e.g. what is the optimal stimulation frequency, what patients can gain from the treatment and how should adjunct treatment be organized.In this thesis, I have had the privilege to explore different methods of evaluating spasticity interventions from a multimodal perspective as a starting point in an effort to understand more of this intriguing phenomenon. Some of the research questions above are already in the “pipeline” for coming studies; others are to be planned by our research group and others.
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| 13. |
- Escala-Garcia, Maria, et al.
(författare)
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A network analysis to identify mediators of germline-driven differences in breast cancer prognosis
- 2020
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the underlying genetic drivers of the heritability of breast cancer prognosis remains elusive. We adapt a network-based approach to handle underpowered complex datasets to provide new insights into the potential function of germline variants in breast cancer prognosis. This network-based analysis studies similar to 7.3 million variants in 84,457 breast cancer patients in relation to breast cancer survival and confirms the results on 12,381 independent patients. Aggregating the prognostic effects of genetic variants across multiple genes, we identify four gene modules associated with survival in estrogen receptor (ER)-negative and one in ER-positive disease. The modules show biological enrichment for cancer-related processes such as G-alpha signaling, circadian clock, angiogenesis, and Rho-GTPases in apoptosis.
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| 14. |
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| 15. |
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| 16. |
- Fredrik, Öhberg, et al.
(författare)
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Gait analysis using a portable motion sensor system : measurements in subjects with hip implant as compared with healthy controls
- 2013
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Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 38:suppl 1, s. 99-100
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.Fig. 1. Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)Figure optionsFig. 2. HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)Figure optionsDiscussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.Reference[1]J. Favre, B.M. Jolles, O. Siegrist, K. AminianQuaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement
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| 17. |
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| 18. |
- Grip, Helena, et al.
(författare)
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A new approach to measure functional stability of the knee based on changes in knee axis orientation
- 2013
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Ingår i: Journal of Biomechanics. - Oxford : Elsevier. - 0021-9290 .- 1873-2380. ; 46:5, s. 855-862
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Tidskriftsartikel (refereegranskat)abstract
- There is a lack of measures that quantify functional knee stability, which is of particular relevance in knee rehabilitation. Therefore, the aim of this study was to investigate the usefulness of knee finite helical axis (FHA) variables in 33 healthy subjects during two different functional tasks; One leg side hop (SH) and Two Leg Squat (TLS), and to investigate correlations of these variables with laxity. Laxity was assessed with a KT-1000 arthrometer and the Beighton Hypermobility Score. Movements were registered with an optical motion capture system. Knee rotation and translation were defined by a six degree of freedom segment model. FHA was calculated for finite steps of 20 degrees knee flexion, based on error simulations. We computed the FHA inclination, the translation along FHA and an FHA Direction Index quantifying directional changes. All variables were repeatable (average ICCs similar to 0.97 during TLS and similar to 0.83 during SH). The lower functional knee stability in SH was reflected by a significantly higher FHA Direction Index and a larger medio-lateral FHA inclination compared to those in TLS. The superior-inferior inclination was smaller during Landing in SH compared to Take-Off and TLS. Translation along FHA was generally small as expected in healthy subjects. Beighton Hypermobility Score and KT-1000 values had weak but significant correlations with FHA Direction Index and FHA translation, which show that laxity influences the functional knee stability. We conclude that FHA measures were sensitive enough to discriminate between SH and TLS. The next step is to investigate the usability of these measures in subjects with knee injury.
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| 19. |
- Grip, Helena, 1973-
(författare)
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Biomechanical assessment of head and neck movements in neck pain using 3D movement analysis
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Three-dimensional movement analysis was used to evaluate head and neck movement in patients with neck pain and matched controls. The aims were to further develop biomechanical models of head and neck kinematics, to investigate differences between subjects with non-specific neck pain and whiplash associated disorders (WAD), and to evaluate the potential of objective movement analysis as a decision support during diagnosis and follow-up of patients with neck pain. Fast, repetitive head movements (flexion, extension, rotation to the side) were studied in a group of 59 subjects with WAD and 56 controls. A back propagation artificial neural network classified vectors of collected movement variables from each individual according to group membership with a predictivity of 89%. The helical axis for head movement were analyzed in two groups of neck pain patients (21 with non-specific neck pain and 22 with WAD) and 24 matched controls. A moving time window with a cut-off angle of 4° was used to calculate finite helical axes. The centre of rotation of the finite axes (CR) was derived as the 3D intersection point of the finite axes. A downward migration of the axis during flexion/extension and a change of axis direction towards the end of the movements were observed. CR was at its most superior position during side rotations and at its most inferior during ball catching. This could relate to that side rotation was mainly done in the upper spine, while all cervical vertebrae were recruited to stabilize the head in the more complex catching task. Changes in movement strategy were observed in the neck pain groups: Neck pain subjects had lower mean velocities and ranges of movements as compared with controls during ball catching, which could relate to a stiffer body position in neck pain patients in order to stabilize the neck. In addition, the WAD group had a displaced axis position during head repositioning after flexion, while CR was displaced during fast side rotations in the non-specific neck pain group. Pain intensity correlated with axis and CR position, and may be one reason for the movement strategy changes. Increased amount of irregularities in the trajectory of the axis was found in the WAD group during head repositioning, fast repetitive head movements and catching. This together with an increased constant repositioning error during repositioning after flexion indicated motor control disturbances. A higher group standard deviation in neck pain groups indicated heterogeneity among subjects in this disturbance. Wireless motion sensors and electro-oculography was used simultaneously, as an initial step towards a portable system and towards a method to quantify head-eye co-ordination deficits in individuals with WAD. Twenty asymptomatic control subjects and six WAD subjects with eye disturbances (e.g. dizziness and double vision) were studied. The trial-to-trial repeatability was moderate to high for all evaluated variables (single intraclass correlation coefficients >0.4 in 28 of 32 variables). The WAD subjects demonstrated decreased head velocity, decreased range of head movement during gaze fixation and lowered head stability during head-eye co-ordination as possible deficits. In conclusion, kinematical analyses have a potential to be used as a support for physicians and physiotherapists for diagnosis and follow-up of neck pain patients. Specifically, the helical axis method gives information about how the movement is performed. However, a flexible motion capture system (for example based on wireless motion sensors) is needed. Combined analysis of several variables is preferable, as patients with different neck pain disorders seem to be a heterogeneous group.
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| 20. |
- Grip, Helena, et al.
(författare)
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Cervical helical axis characteristics and its center of rotation during active head and upper arm movements-comparisons of whiplash-associated disorders, non-specific neck pain and asymptomatic individuals.
- 2008
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Ingår i: Journal of Biomechanics. - : Springer. - 0021-9290 .- 1873-2380. ; 41:13, s. 2799-2805
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Tidskriftsartikel (refereegranskat)abstract
- The helical axis model can be used to describe translation and rotation of spine segments. The aim of this study was to investigate the cervical helical axis and its center of rotation during fast head movements (side rotation and flexion/extension) and ball catching in patients with non-specific neck pain or pain due to whiplash injury as compared with matched controls. The aim was also to investigate correlations with neck pain intensity. A finite helical axis model with a time-varying window was used. The intersection point of the axis during different movement conditions was calculated. A repeated-measures ANOVA model was used to investigate the cervical helical axis and its rotation center for consecutive levels of 15 degrees during head movement. Irregularities in axis movement were derived using a zero-crossing approach. In addition, head, arm and upper body range of motion and velocity were observed. A general increase of axis irregularity that correlated to pain intensity was observed in the whiplash group. The rotation center was superiorly displaced in the non-specific neck pain group during side rotation, with the same tendency for the whiplash group. During ball catching, an anterior displacement (and a tendency to an inferior displacement) of the center of rotation and slower and more restricted upper body movements implied a changed movement strategy in neck pain patients, possibly as an attempt to stabilize the cervical spine during head movement.
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