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Lindahl, O. A., Bäcklund, T., Ramser, K., Liv, P., Ljungberg, B. & Bergh, A. (2021). A tactile resonance sensor for prostate cancer detection - Evaluation on human prostate tissue. Biomedical Engineering & Physics Express, 7(2), Article ID 025017.
Open this publication in new window or tab >>A tactile resonance sensor for prostate cancer detection - Evaluation on human prostate tissue
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2021 (English)In: Biomedical Engineering & Physics Express, E-ISSN 2057-1976, Vol. 7, no 2, article id 025017Article in journal (Refereed) Published
Abstract [en]

Prostate cancer surgery risks erectile problems and incontinence for the patient. An instrument for guiding surgeons to avoid nerve bundle damage and ensure complete cancer removal is desirable. We present a tactile resonance sensor made of PZT ceramics, mounted in a 3D motorized translation stage for scanning and measuring tissue stiffness for detecting cancer in human prostate. The sensor may be used during surgery for guidance, scanning the prostate surface for the presence of cancer, indicating migration of cancer cells into surrounding tissue. Ten fresh prostates, obtained from patients undergoing prostate cancer surgery, were cut into 0.5 cm thick slices. Each slice was measured for tissue stiffness at about 25 different sites and compared to histology for validation cancer prediction by stiffness. The statistical analysis was based on a total of 148 sites with non-cancer and 40 sites with cancer. Using a generalized linear mixed model (GLMM), the stiffness data predicted cancer with an area under the curve of 0.74, after correcting for overfitting using bootstrap validation. Mean prostate stiffness on the logarithmic scale (p = 0.015) and standardized Z-scores (p = 0.025) were both significant predictors of cancer. This study concludes that stiffness measured by the tactile resonance sensor is a significant predictor of prostate cancer with potential for future development towards a clinical instrument for surgical guidance.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2021
Keywords
prostate cancer, resonance sensor, stiffness
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-182116 (URN)10.1088/2057-1976/abe681 (DOI)000624514500001 ()2-s2.0-85103171622 (Scopus ID)
Available from: 2021-04-09 Created: 2021-04-09 Last updated: 2023-09-05Bibliographically approved
Bäcklund, T., Grip, H., Öhberg, F. & Sundström, N. (2021). Single sensor measurement of heel-height during the push-off phase of gait. Physiological Measurement, 42(10), Article ID 105016.
Open this publication in new window or tab >>Single sensor measurement of heel-height during the push-off phase of gait
2021 (English)In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 42, no 10, article id 105016Article in journal (Refereed) Published
Abstract [en]

Objective: In healthy gait a forceful push-off is needed to get an efficient leg swing and propulsion, and a high heel lift makes a forceful push-off possible. The power of the push-off is decreased with increased age and in persons with impaired balance and gait. The aim of this study was to evaluate whether a wearable equipment (Striton) and algorithms to estimate vertical heel-height during gait from a single optical distance sensor is reliable and feasible for clinical applications.

Approach: To assess heel-height with the Striton system an optical distance sensor was used to measure the distance to the floor along the shank. An algorithm was created to transform this measure to a vertical distance. The heel-height was validated in an experimental setup, against a 3D motion capture system (MCS), and test-retest and day-to-day tests were performed on 10 elderly persons. As a reference material 83 elderly persons were included, and heel-height was measured before and after surgery in four patients with the neurological disorder idiopathic normal pressure hydrocephalus (iNPH).

Main results: In the experimental setup the accuracy was high with a maximum error of 2% at all distances, target colours and inclination angles, and the correlation to the MCS was R = 0.94. Test-retest and day-to-day tests were equal within ±1.2 cm. Mean heel-height of the elderly persons was 16.5 ± 0.6 cm and in the patients with iNPH heel-height was increased from 11.2 cm at baseline to 15.3 cm after surgery.

Significance: Striton can reliably measure heel-height during gait, with low test-retest and day-to-day variability. The system was easy to attach, and simple to use, which makes it suitable for clinical applications.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2021
Keywords
heel-height, optical sensor, heel-height variability, push-off phase
National Category
Medical Engineering
Research subject
medical informatics
Identifiers
urn:nbn:se:umu:diva-182776 (URN)10.1088/1361-6579/ac325c (DOI)000723408600001 ()34678800 (PubMedID)2-s2.0-85122532235 (Scopus ID)
Note

Previously included in thesis in manuscript form. 

Available from: 2021-05-04 Created: 2021-05-04 Last updated: 2024-05-13Bibliographically approved
Bäcklund, T. (2021). Wearable systems and sensors for the assessment of motor control: Development and validation of methods for clinical assessment of idiopathic normal pressure hydrocephalus. (Doctoral dissertation). Umeå: Umeå Universitet
Open this publication in new window or tab >>Wearable systems and sensors for the assessment of motor control: Development and validation of methods for clinical assessment of idiopathic normal pressure hydrocephalus
2021 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Bärbara system och sensorer för bedömning av motorisk kontroll : Utveckling och validering av metoder för klinisk bedömning av idiopatisk normaltryckshydrocefalus
Abstract [en]

Human gait and balance are controlled by automatic processes in the central nervous system, and in sensory and proprioceptive systems. If a disturbance occurs in any of these complex structures, it may lead to balance and gait problems. Equally important are the systems controlling the upper extremity functions where reach, grasp and manipulation skills may be affected. For the neurodegenerative disease idiopathic normal pressure hydrocephalus (iNPH), balance and gait disturbances are cardinal symptoms. Motor control of the upper extremities is also affected. In clinic today, physical impairment of persons with iNPH is commonly visually assessed using subjective, course tests with ordinal scales with the risk of missing minor changes. There is a lack of objective and quantitative ways to measure motor control in daily patient care. The aim of this thesis was to develop and validate tools for objective assessment of parameters that affect motor control in persons with iNPH.

Postural stability in stance and walking was assessed using gyroscopes in patients with iNPH, healthy elderly (HE) and patients with ventriculomegaly (VM). Compared to HE, patients with iNPH had reduced postural stability and relied less on vision. iNPH patients also had a lower trunk sway velocity than VM during walking. The gyroscopic system could quantitatively assess postural deficits in iNPH, making it a potentially useful tool for diagnosis and for clinical follow-up. The differences found during gait also suggests that walking, rather than quiet stance, should be further investigated for facilitating differential diagnosis compared to other patient groups with ventriculomegaly.

The gait in patients with iNPH is according to guidelines defined as slow, shuffling with a low foot-lift, and wide based. To objectively quantify the latter two features, a system (Striton) was developed in-house to assess the increased distance between the feet and the peak heel-height at the push-off phase of the gait cycle. It was validated in experimental setups, compared to gold standard motion capture systems (MCS), on healthy elderly (HE), through test-retest and day-to-day evaluations, and in four patients with iNPH. Striton demonstrated high correlations, in step-width and in heel-height, compared with the MCS. The mean step-width in the HE was 5.2 ± 0.9 cm (mean±Standard Deviation) and the heel-height 16.7±0.6 cm. Test-retest and day-to-day variations were small, ±0.5 cm in step-width and ±1.2 cm in heel-height, and differences in the parameters were seen between HE and iNPH both before and after surgery. Thus, Striton has the potential of quantitatively assessing gait parameters in HE and iNPH in a valuable manner.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2021. p. 50
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 2130
Keywords
Gait, step-width, heel-heigt, balance, trunk sway, idiopathic normal pressure hydrocephalus, IMU, Inter-rater reliability, kinematics
National Category
Medical Engineering Neurology
Research subject
medical informatics
Identifiers
urn:nbn:se:umu:diva-182784 (URN)978-91-7855-523-9 (ISBN)978-91-7855-524-6 (ISBN)
Public defence
2021-06-04, Betula, Norrlands Universitetssjukhus, Umeå, 09:00 (Swedish)
Opponent
Supervisors
Note

Disputationen sänds även via Zoom.

Available from: 2021-05-12 Created: 2021-05-04 Last updated: 2021-12-06Bibliographically approved
Bäcklund, T., Öhberg, F., Johansson, G., Grip, H. & Sundström, N. (2020). Novel, clinically applicable method to measure step-width during the swing phase of gait. Physiological Measurement, 41(6), Article ID 065005.
Open this publication in new window or tab >>Novel, clinically applicable method to measure step-width during the swing phase of gait
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2020 (English)In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 41, no 6, article id 065005Article in journal (Refereed) Published
Abstract [en]

Objective: Step-width during walking is an indicator of stability and balance in patients with neurological disorders, and development of objective tools to measure this clinically would be a great advantage. The aim of this study was to validate an in-house-developed gait analysis system (Striton), based on optical and inertial sensors and a novel method for stride detection, for measuring step-width during the swing phase of gait and temporal parameters.

Approach: The step-width and stride-time measurements were validated in an experimental setup, against a 3D motion capture system and on an instrumented walkway. Further, test-retest and day-to-day variability were evaluated, and gait parameters were collected from 87 elderly persons (EP) and four individuals with idiopathic normal pressure hydrocephalus (iNPH) before/after surgery.

Main results: Accuracy of the step-width measurement was high: in the experimental setup mean error was 0.08 +/- 0.25 cm (R = 1.00) and against the 3D motion capture system 0.04 +/- 1.12 cm (R = 0.98). Test-retest and day-to-day measurements were equal within +/- 0.5 cm. Mean difference in stride time was -0.003 +/- 0.008 s between Striton and the instrumented walkway. The Striton system was successfully applied in the clinical setting on individuals with iNPH, which had larger step-width (6.88 cm, n = 4) compared to EP (5.22 cm, n = 87).

Significance: We conclude that Striton is a valid, reliable and wearable system for quantitative assessment of step-width and temporal parameters during gait. Initial measurements indicate that the newly defined step-width parameter differs between EP and patients with iNPH and before/after surgery. Thus, there is potential for clinical applicability in patients with reduced gait stability.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2020
Keywords
gait, swing phase, step-width, inertial measurement unit, wearable, optical sensor
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-173753 (URN)10.1088/1361-6579/ab95ed (DOI)000548816000001 ()32442989 (PubMedID)2-s2.0-85087528902 (Scopus ID)
Available from: 2020-07-31 Created: 2020-07-31 Last updated: 2024-07-02Bibliographically approved
Öhberg, F., Bäcklund, T., Sundström, N. & Grip, H. (2019). Portable Sensors Add Reliable Kinematic Measures to the Assessment of Upper Extremity Function. Sensors, 19(5), Article ID 1241.
Open this publication in new window or tab >>Portable Sensors Add Reliable Kinematic Measures to the Assessment of Upper Extremity Function
2019 (English)In: Sensors, E-ISSN 1424-8220, Vol. 19, no 5, article id 1241Article in journal (Refereed) Published
Abstract [en]

Ordinal scales with low resolution are used to assess arm function in clinic. These scales may be improved by adding objective kinematic measures. The aim was to analyze within-subject, inter-rater and overall reliability (i.e., including within-subject and inter-rater reliability) and check the system's validity of kinematic measures from inertial sensors for two such protocols on one person. Twenty healthy volunteers repeatedly performed two tasks, finger-to-nose and drinking, during two test sessions with two different raters. Five inertial sensors, on the forearms, upper arms and xiphoid process were used. Comparisons against an optical camera system evaluated the measurement validity. Cycle time, range of motion (ROM) in shoulder and elbow were calculated. Bland-Altman plots and linear mixed models including the generalizability (G) coefficient evaluated the reliability of the measures. Within-subject reliability was good to excellent in both tests (G = 0.80-0.97) and may serve as a baseline when assessing upper extremities in future patient groups. Overall reliability was acceptable to excellent (G = 0.77-0.94) for all parameters except elbow axial rotation in finger-to-nose task and both elbow axial rotation and flexion/extension in drinking task, mainly due to poor inter-rater reliability in these parameters. The low to good reliability for elbow ROM probably relates to high within-subject variability. The sensors provided good to excellent measures of cycle time and shoulder ROM in non-disabled individuals and thus have the potential to improve today's assessment of arm function.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
inter-rater reliability, inertial sensor, kinematics, upper limb, arm function
National Category
Physiotherapy
Identifiers
urn:nbn:se:umu:diva-158105 (URN)10.3390/s19051241 (DOI)000462540400260 ()30870999 (PubMedID)2-s2.0-85062987798 (Scopus ID)
Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2023-03-24Bibliographically approved
Bäcklund, T., Öhberg, F., Grip, H., Johansson, G. & Sundström, N. (2018). O 035 - A novel method to measure step width during the swing phase of gait. Gait & Posture, 65, 71-72
Open this publication in new window or tab >>O 035 - A novel method to measure step width during the swing phase of gait
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2018 (English)In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 65, p. 71-72Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physiotherapy
Identifiers
urn:nbn:se:umu:diva-203638 (URN)10.1016/j.gaitpost.2018.06.053 (DOI)30146313 (PubMedID)2-s2.0-85052087299 (Scopus ID)
Available from: 2023-01-19 Created: 2023-01-19 Last updated: 2024-07-02Bibliographically approved
Lindahl, O. A., Ramser, K., Bäcklund, T., Ljungberg, B. & Bergh, A. (2018). Prostate cancer detection ex vivo combining Raman spectroscopy and tactile resonance technology. In: Eskola, H Vaisanen, O Viik, J Hyttinen, J (Ed.), EMBEC & NBC 2017: . Paper presented at Joint Conference of the European Medical and Biological Engineering Conference (EMBEC) / Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC), JUN, 2017, Tampere, FINLAND (pp. 193-196). SPRINGER-VERLAG SINGAPORE PTE LTD
Open this publication in new window or tab >>Prostate cancer detection ex vivo combining Raman spectroscopy and tactile resonance technology
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2018 (English)In: EMBEC & NBC 2017 / [ed] Eskola, H Vaisanen, O Viik, J Hyttinen, J, SPRINGER-VERLAG SINGAPORE PTE LTD , 2018, p. 193-196Conference paper, Published paper (Refereed)
Abstract [en]

Prostate cancer is the most common cancer for men in the western world. The most prevalent curative treatment is radical prostatectomy. However, prostate surgery can give unwanted side effects and there is a need for an instrument that can provide decision support to the surgeon during surgery on the presence of cancer cells in the surgical margin. A dual modality probe, combining Raman spectroscopy and tactile resonance technology, has been used for detecting cancer in fresh human prostate tissue. The tactile resonance modality measures the tissue stiffness and Raman spectroscopy depicts the molecular content in tissue, both related to cancer. After ethical approval, the study investigated the potential of the dual-modality probe by testing its ability to differentiate between normal and cancerous prostate tissue ex vivo. It also investigated the minimal amount of measurement points needed to securely detect cancer on the surface of prostate tissue. Measurements on three prostate tissue slices show that the tactile resonance modality measuring stiffness was able to detect differences between normal and cancerous tissue on a significant level of 90%, but the sample size was too low to draw any firm conclusions. It was also suggested from the study results that the high wavenumber region in the Raman spectrum can give valuable information about cancer in prostate tissue. A number of 24 measurement points were enough for detecting cancer in prostate slices in this study. It can be suggested from this study that combining these two sensor modalities is promising for accurate detection of prostate cancer that is needed during prostate surgery, but more measurements including more prostates must be performed before the full value of the study result can be established.

Place, publisher, year, edition, pages
SPRINGER-VERLAG SINGAPORE PTE LTD, 2018
Series
IFMBE Proceedings, ISSN 1680-0737 ; 65
Keywords
Raman spectroscopy, tactile resonance technology, prostate cancer, radical prostatectomy, surgical margin
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-155049 (URN)10.1007/978-981-10-5122-7_49 (DOI)000449778900049 ()2-s2.0-85021733002 (Scopus ID)978-981-10-5121-0 (ISBN)978-981-10-5122-7 (ISBN)
Conference
Joint Conference of the European Medical and Biological Engineering Conference (EMBEC) / Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC), JUN, 2017, Tampere, FINLAND
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2023-03-23Bibliographically approved
Bäcklund, T., Frankel, J., Israelsson, H., Malm, J. & Sundström, N. (2017). Trunk sway in idiopathic normal pressure hydrocephalus: quantitative assessment in clinical practice. Gait & Posture, 62-70, Article ID 54.
Open this publication in new window or tab >>Trunk sway in idiopathic normal pressure hydrocephalus: quantitative assessment in clinical practice
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2017 (English)In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, p. 62-70, article id 54Article in journal (Refereed) Published
Abstract [en]

Background: In diagnosis and treatment of patients with idiopathic normal pressure hydrocephalus (iNPH), there is need for clinically applicable, quantitative assessment of balance and gait. Using a body worn gyroscopic system, the aim of this study was to assess postural stability of iNPH patients in standing, walking and during sensory deprivation before and after cerebrospinal fluid (CSF) drainage and surgery. A comparison was performed between healthy elderly (HE) and patients with various types of hydrocephalus (ventriculomegaly (VM)).

Methods: Trunk sway was measured in 31 iNPH patients, 22 VM patients and 58 HE. Measurements were performed at baseline in all subjects, after CSF drainage in both patient groups and after shunt surgery in the iNPH group.

Results: Preoperatively, the iNPH patients had significantly higher trunk sway compared to HE, specifically for the standing tasks (p < 0.001). Compared to VM, iNPH patients had significantly lower sway velocity during gait in three of four cases on firm support (p < 0.05). Sway velocity improved after CSF drainage and in forward-backward direction after surgery (p < 0.01). Compared to HE both patient groups demonstrated less reliance on visual input to maintain stable posture.

Conclusions: INPH patients had reduced postural stability compared to HE, particularly during standing, and for differentiation between iNPH and VM patients sway velocity during gait is a promising parameter. A reversible reduction of visual incorporation during standing was also seen. Thus, the gyroscopic system quantitatively assessed postural deficits in iNPH, making it a potentially useful tool for aiding in future diagnoses, choices of treatment and clinical follow-up. 

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Idiopathic normal pressure hydrocephalus, Trunk sway, Balance, Gait, Gyroscope
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:umu:diva-138239 (URN)10.1016/j.gaitpost.2017.02.017 (DOI)000405044400011 ()28259041 (PubMedID)2-s2.0-85014113899 (Scopus ID)
Available from: 2017-08-16 Created: 2017-08-16 Last updated: 2023-03-23Bibliographically approved
Hellström, T., Lindahl, O., Bäcklund, T., Karlsson, M., Hohnloser, P., Bråndal, A., . . . Wester, P. (2016). An intelligent rollator for mobility impaired persons, especially stroke patients. Journal of Medical Engineering & Technology, 40(5), 270-279
Open this publication in new window or tab >>An intelligent rollator for mobility impaired persons, especially stroke patients
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2016 (English)In: Journal of Medical Engineering & Technology, ISSN 0309-1902, E-ISSN 1464-522X, Vol. 40, no 5, p. 270-279Article in journal (Refereed) Published
Abstract [en]

An intelligent rollator (IRO) was developed that aims at obstacle detection and guidance to avoid collisions and accidental falls. The IRO is a retrofit four-wheeled rollator with an embedded computer, two solenoid brakes, rotation sensors on the wheels and IR-distance sensors. The value reported by each distance sensor was compared in the computer to a nominal distance. Deviations indicated a present obstacle and caused activation of one of the brakes in order to influence the direction of motion to avoid the obstacle. The IRO was tested by seven healthy subjects with simulated restricted and blurred sight and five stroke subjects on a standardised indoor track with obstacles. All tested subjects walked faster with intelligence deactivated. Three out of five stroke patients experienced more detected obstacles with intelligence activated. This suggests enhanced safety during walking with IRO. Further studies are required to explore the full value of the IRO.

Place, publisher, year, edition, pages
Taylor & Francis, 2016
Keywords
Assistive technology, intelligent walker, stroke
National Category
Clinical Medicine Medical Engineering
Identifiers
urn:nbn:se:umu:diva-131356 (URN)10.3109/03091902.2016.1167973 (DOI)27078084 (PubMedID)2-s2.0-84963611927 (Scopus ID)
Available from: 2017-02-13 Created: 2017-02-13 Last updated: 2024-07-02Bibliographically approved
Eklund, A., Bäcklund, T. & Henein, M. Y. (2013). Natural angioplasty as a mechanical effect of exercise [Letter to the editor]. International Journal of Cardiology, 168(3), 3083-3085
Open this publication in new window or tab >>Natural angioplasty as a mechanical effect of exercise
2013 (English)In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 168, no 3, p. 3083-3085Article in journal, Letter (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
Angioplasty, Exercise, Coronary stenosis
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-79945 (URN)10.1016/j.ijcard.2013.04.084 (DOI)000326184400291 ()23643420 (PubMedID)2-s2.0-84885608539 (Scopus ID)
Available from: 2013-09-04 Created: 2013-09-04 Last updated: 2023-03-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7431-8335

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