1. |
- Alt Murphy, Margit, 1970, et al.
(author)
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Acceleration based activity metrics during subacute inpatient stroke rehabilitation
- 2016
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In: Procedia Technology, Biosensors 2016, 25-27 May, Göteborg, Sweden..
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Conference paper (other academic/artistic)abstract
- People after stroke have difficulties to reach sufficient physical activity level during their rehabilitation and particularly outside the therapy time. We aim to quantify activity levels and investigate differences in motor activity in weekdays and weekends in a subacute stage after stroke. Data from multiple three-axis accelerometers was collected during two 48h sessions in 11 patients. The activity level and symmetry indices were sensitive to variations in weekend and weekdays. This information is valuable in rehabilitation planning and management and enables identification of those in risk of low physical activity and inactivity.
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2. |
- Alt Murphy, Margit, 1970, et al.
(author)
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An upper body garment with integrated sensors for people with neurological disorders – early development and evaluation
- 2019
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In: BMC Biomedical Engineering. - : Springer Science and Business Media LLC. - 2524-4426. ; 1:3
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Journal article (peer-reviewed)abstract
- Background: To develop a novel wearable garment with integrated sensors for continuous monitoring of physiological and movement related variables to evaluate progression, tailor treatments and improve diagnosis in epilepsy, Parkinson’s disease and stroke. Methods: An iterative development process and evaluation of an upper body garment with integrated sensors included: identification of user needs, specification of technical and garment requirements, garment development and production as well as evaluation of garment design, functionality and usability. The project is a multidisciplinary collaboration with experts from medical, engineering, textile, and material science within the wearITmed consortium. The work was organized in regular meetings, task groups and hands-on workshops. User needs were identified using results from a mixed-methods systematic review, a focus group study and expert groups. Usability was evaluated in 19 individuals (13 controls, 6 patients with Parkinson’s disease) using semi-structured interviews and qualitative content analysis. Results: A prototype designed to monitor movements and heart rate was developed. The garment was well accepted by the users regarding design and comfort, although the users were cautious about the technology and suggested improvements. All electronic components passed a washability test. The most robust data was obtained from accelerometer and gyroscope sensors while the electrodes for heart rate registration were sensitive to motion. artefacts. The algorithm development within the wearITmed consortium has shown promising results. Conclusions: The prototype was accepted by the users. Technical improvements are needed, but preliminary data indicate that the garment has potential to be used as a tool for diagnosis and treatment selection and could provide added value for monitoring seizures in epilepsy, fluctuations in PD and activity levels in stroke. Future work aims to improve the prototype further, develop algorithms, and evaluate the functionality and usability in targeted patient groups. The potential of incorporating blood pressure and heart-rate variability monitoring will also be explored.
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3. |
- Alt Murphy, Margit, 1970, et al.
(author)
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Comparison of Accelerometer-Based Arm, Leg and Trunk Activity at Weekdays and Weekends During Subacute Inpatient Rehabilitation After Stroke
- 2019
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In: Journal of Rehabilitation Medicine. - : Medical Journals Sweden AB. - 1650-1977 .- 1651-2081. ; 51:6, s. 426-433
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Journal article (peer-reviewed)abstract
- Objective: To determine whether there are differences in arm, leg and trunk activity measured by acceleration between weekdays and weekends in people undergoing rehabilitation in the subacute stage after stroke. Patients: Twenty-eight individuals with stroke (mean age 55.4 years; severe to mild impairment) and 10 healthy controls. Methods: A set of 5 3-axial accelerometers were used on the trunk, wrists and ankles during 2 48-h sessions at weekdays and over a weekend. Day-time acceleration raw data were expressed as the signal magnitude area. Asymmetry between the affected and less-affected limb was calculated as a ratio. Results: Participants with stroke used their both arms and legs less at weekends than on weekdays (p<0.05, effect size 0.3 2-0.5 7). Asymmetry between the affected and less-affected arm was greater at weekends (p < 0.05, effect size 0.32). All activity measures, apart from the less-affected arm on weekdays, were lower in stroke compared with controls (p<0.05, effect size 0.4-0.8). No statistically significant differences were detected between weekday and weekend activity for the control group. One-third of participants perceived the trunk sensor as inconvenient to wear. Conclusion: Increased focus needs to be applied on activities carried out during weekends at rehabilitation wards.
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4. |
- Andersson, Sofi A., 1970, et al.
(author)
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Arm impairment and walking speed explain real-life activity of the affected Arm and leg after stroke
- 2021
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In: Journal of Rehabilitation Medicine. - : Foundation for Rehabilitation Information. - 1650-1977 .- 1651-2081. ; 53:6
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Journal article (peer-reviewed)abstract
- Objective: To determine to what extent accelerometer-based arm, leg and trunk activity is associated with sensorimotor impairments, walking capacity and other factors in subacute stroke. Design: Cross-sectional study. Patients: Twenty-six individuals with stroke (mean age 55.4 years, severe to mild motor impairment). Methods: Data on daytime activity were collected over a period of 4 days from accelerometers placed on the wrists, ankles and trunk. A forward stepwise linear regression was used to determine associations between free-living activity, clinical and demographic variables. Results: Arm motor impairment (Fugl-Meyer Assessment) and walking speed explained more than 60% of the variance in daytime activity of the more-affected arm, while walking speed alone explained 60% of the more-affected leg activity. Activity of the less-affected arm and leg was associated with arm motor impairment (R2=0.40) and independence in walking (R2=0.59). Arm activity ratio was associated with arm impairment (R2=0.63) and leg activity ratio with leg impairment (R2=0.38) and walking speed (R2=0.27). Walking-related variables explained approximately 30% of the variance in trunk activity. Conclusion: Accelerometer-based free-living activity is dependent on motor impairment and walking capacity. The most relevant activity data were obtained from more-affected limbs. Motor impairment and walking speed can provide some information about real-life daytime activity levels.
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5. |
- Johansson, Dongni, 1988, et al.
(author)
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Tonic-clonic seizure detection using accelerometry-based wearable sensors: A prospective, video-EEG controlled study
- 2019
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In: Seizure : the journal of the British Epilepsy Association. - : Elsevier BV. - 1059-1311 .- 1532-2688. ; 65, s. 48-54
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Journal article (peer-reviewed)abstract
- Purpose: The aim of this prospective, video-electroencephalography (video-EEG) controlled study was to evaluate the performance of an accelerometry-based wearable system to detect tonic-clonic seizures (TCSs) and to investigate the accuracy of different seizure detection algorithms using separate training and test data sets. Methods: Seventy-five epilepsy surgery candidates undergoing video-EEG monitoring were included. The patients wore one three-axis accelerometer on each wrist during video-EEG. The accelerometer data was band-pass filtered and reduced using a movement threshold and mapped to a time-frequency feature space representation. Algorithms based on standard binary classifiers combined with a TCS specific event detection layer were developed and trained using the training set. Their performance was evaluated in terms of sensitivity and false positive (FP) rate using the test set. Results: Thirty-seven available TCSs in 11 patients were recorded and the data was divided into disjoint training (27 TCSs, three patients) and test (10 TCSs, eight patients) data sets. The classification algorithms evaluated were K-nearest-neighbors (KNN), random forest (RF) and a linear kernel support vector machine (SVM). For the TCSs detection performance of the three algorithms in the test set, the highest sensitivity was obtained for KNN (100% sensitivity, 0.05 FP/h) and the lowest FP rate was obtained for RF (90% sensitivity, 0.01 FP/h). Conclusions: The low FP rate enhances the clinical utility of the detection system for long-term reliable seizure monitoring. It also allows a possible implementation of an automated TCS detection in free-living environment, which could contribute to ascertain seizure frequency and thereby better seizure management.
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6. |
- Karlsson, Helene, et al.
(author)
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Quality assurance of encapsulation architecture, including subsequent washing process for permanently mounted wearable sensors
- 2018
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In: 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac). - 9789526815053 ; , s. 14-23
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Conference paper (peer-reviewed)abstract
- The overall objective of the project wearITmed, Wearable sensors in smart textiles, is to develop a novel wearable sensor system demonstrator. This sensor system aims to monitor symptoms of neurological disorders such as epilepsy, Parkinson’s disease and stroke. The wearable sensor system demonstrator, including both integrated gyros/accelerometers and textile sensors, is useful for the evaluation of clinically relevant movement patterns and other physiological parameters, and further to establish disease discriminating and treatment responsive objective variables. The work presented in this paper is focused on ensuring that the wearable sensor system can be cleaned and washed without first removing the electronics. The work includes three main areas; the adhesion and architecture, the molding and finally the washing test performance. Standard wettability and peel tests (Volvo Standard STD 185–0001) were performed on standard test board IPC-B-5 and IPC-9202 test vehicle for selecting the best adhesive and encapsulation materials in form of an epoxy (Epotek 302–3M) and a medical approved silicone (Nusil MED-6019). The molded components were washtested (Standard SS-EN ISO 6330:2012) followed by testing of the electrical resistance (Standard IPC-9202). As a result a total of 22 garments were produced with four individually mounted boards in each garment. The tests showed that the wearable sensors passed the washing tests and were still functional after 10 repeated washing cycles without any change or degradation in resistance or sign of electrical failure. The wearable electronics therefore meets the requirements of being simultaneously resistant to; water, temperature (40 °C), chemical detergents and dynamic forces.
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7. |
- Montagnoli, Antonio, et al.
(author)
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Non-destructive phenotypic analysis of early stage tree seedling growth using an automated stereovision imaging method
- 2016
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In: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 7
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Journal article (peer-reviewed)abstract
- A plant phenotyping approach was applied to evaluate growth rate of containerized tree seedlings during the precultivation phase following seed germination. A simple and affordable stereo optical system was used to collect stereoscopic red-green-blue (RGB) images of seedlings at regular intervals of time. Comparative analysis of these images by means of a newly developed software enabled us to calculate (a) the increments of seedlings height and (b) the percentage greenness of seedling leaves. Comparison of these parameters with destructive biomass measurements showed that the height traits can be used to estimate seedling growth for needle-leaved plant species whereas the greenness trait can be used for broad-leaved plant species. Despite the need to adjust for plant type, growth stage and light conditions this new, cheap, rapid, and sustainable phenotyping approach can be used to study large-scale phenome variations due to genome variability and interaction with environmental factors.
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8. |
- Schaller, Vincent, 1979, et al.
(author)
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Motion of nanometer sized magnetic particles in a magnetic field gradient
- 2008
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 104:9, s. no:093918-
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Journal article (peer-reviewed)abstract
- Using magnetic particles with sizes in the nanometer range in biomedical magnetic separation has gained much interest recently due to their higher surface area to particle volume and lower sedimentation rates. In this paper, we report our both theoretical and experimental investigation of the motion of magnetic particles in a magnetic field gradient with particle sizes from 425 nm down to 50 nm. In the experimental measurements, we monitor the absorbance change of the sample volume as the particle concentration varies over time. We also implement a Brownian dynamics algorithm to investigate the influence of particle interactions during the separation and compare it to the experimental results for validation. The simulation agrees well with the measurements for particle sizes around 425 nm. Some discrepancies remain for smaller particle sizes, which may indicate that additional factors also influence the separation for the smaller size range. We observe that the separation process includes the formation of chainlike particle aggregates due to the magnetic dipole-dipole interactions between particles when subjected to an external magnetic field. We can also see that the hydrodynamic interaction between these chains contributes to reducing the separation time. In conclusion, we show that the formation of these particle aggregates, and to a less extent the hydrodynamic interactions between them contributes to significantly enhancing the particle separation process. © 2008 American Institute of Physics.
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10. |
- Soroudi, Azadeh, et al.
(author)
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Surface modification of textile electrodes to improve electrocardiography signals in wearable smart garment
- 2019
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In: Journal of materials science. Materials in electronics. - : Springer New York LLC. - 0957-4522 .- 1573-482X. ; 30:17, s. 16666-16675
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Journal article (peer-reviewed)abstract
- Recording high quality biosignals by dry textile electrodes is a common challenge in medical health monitoring garments. The aim of this study was to improve skin–electrode interface and enhance the quality of recorded electrocardiography (ECG) signals by modification of textile electrodes embedded in WearItMed smart garment. The garment has been developed for long-term health monitoring in patients suffering from epilepsy and Parkinson’s disease. A skin-friendly electro-conductive elastic paste was formulated to coat and modify the surface of the knitted textile electrodes. The modifications improved the surface characteristics of the electrodes by promoting a more effective contact area between skin and electrode owing to a more even surface, fewer pores, greater surface stability against touch, and introduction of humidity barrier properties. The modifications decreased the skin–electrode contact impedance, and consequently improved the recorded ECG signals obviously when low pressure was applied to the electrodes, therefore contributed to greater patient comfort. The created contact surface allowed the natural humidity of the skin/sweat to ease the signal transfer between the electrode and the body, while introducing a shorter settling time and retaining moisture over a longer time. Microscopic images, ECG signal measurements, electrode–skin contact impedance at different pressures and times, and water absorbency were measured and reported.
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