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Publications (10 of 13) Show all publications
Yang, L., Lu, K., Forsman, M., Lindecrantz, K., Seoane, F., Ekblom, Ö. & Eklund, J. (2019). Evaluation of physiological workload assessment methods using heart rate and accelerometry for a smart wearable system. Ergonomics
Open this publication in new window or tab >>Evaluation of physiological workload assessment methods using heart rate and accelerometry for a smart wearable system
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2019 (English)In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847Article in journal (Other academic) Accepted
Abstract [en]

Work metabolism (WM) can be accurately estimated by oxygen consumption (VO2), which is commonly assessed by heart rate (HR) in field studies. However, the VO2–HR relationship is influenced by individual capacity and activity characteristics. The purpose of this study was to evaluate three models for estimating WM compared with indirect calorimetry, during simulated work activities. The techniques were: the HR-Flex model; HR branched model, combining HR with hip-worn accelerometers (ACC); and HR + arm-leg ACC model, combining HR with wrist- and thigh-worn ACC. Twelve participants performed five simulated work activities and three submaximal tests. The HR + arm-leg ACC model had the overall best performance with limits of agreement (LoA) of −3.94 and 2.00 mL/min/kg, while the HR-Flex model had −5.01 and 5.36 mL/min/kg and the branched model, −6.71 and 1.52 mL/min/kg. In conclusion, the HR + arm-leg ACC model should, when feasible, be preferred in wearable systems for WM estimation.

Keywords
Heart rate; work metabolism; motion sensing; wearable sensors; risk assessment; estimation models
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-239148 (URN)10.1080/00140139.2019.1566579 (DOI)000468779800007 ()2-s2.0-85062366366 (Scopus ID)
Funder
AFA Insurance, 150039
Note

QC 20190218

Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2019-06-11Bibliographically approved
Lu, K., Yang, L., Abtahi, F., Lindecrantz, K., Rödby, K. & Seoane, F. (2019). Wearable cardiorespiratory monitoring system for unobtrusive free-living energy expenditure tracking. In: IFMBE Proceedings: . Paper presented at World Congress on Medical Physics and Biomedical Engineering, WC 2018, 3 June 2018 through 8 June 2018 (pp. 433-437). Springer (1)
Open this publication in new window or tab >>Wearable cardiorespiratory monitoring system for unobtrusive free-living energy expenditure tracking
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2019 (English)In: IFMBE Proceedings, Springer, 2019, no 1, p. 433-437Conference paper, Published paper (Refereed)
Abstract [en]

In this work, we want to introduce combined heart rate and respiration monitoring for more accurate energy expenditure tracking on free-living subjects. We have developed a wearable cardiorespiratory monitoring system with unobtrusive heart rate measurement and ventilation estimation function for this purpose. The system is based on a garment with integrated textile electrodes for one-lead electrocardiogram and impedance pneumography measurements. A pilot experiment has been performed to prove the concept and to evaluate the characteristics of heart rate and ventilation estimated by our system in relation to energy expenditure. In the experiment, ventilation shows a better linearity in relation to the energy expenditure at the low intensity region than heart rate. Based on these characteristics, a model combining heart rate and ventilation for energy expenditure estimation is proposed which shows a significantly lower estimation error than the heart rate only model.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Energy expenditure, Impedance pneumography, Wearable devices, Biomedical engineering, Patient monitoring, Wearable technology, Energy expenditure estimation, Estimation function, Heart rate measurements, Respiration monitoring, Textile electrodes, Heart
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-236338 (URN)10.1007/978-981-10-9035-6_80 (DOI)000450908300080 ()2-s2.0-85048260818 (Scopus ID)
Conference
World Congress on Medical Physics and Biomedical Engineering, WC 2018, 3 June 2018 through 8 June 2018
Funder
VINNOVA
Note

QC 20181109

Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2018-12-11Bibliographically approved
Lu, K., Holzmann, M., Abtahi, F., Lindecrantz, K., Lindqvist, P. G. & Nordström, L. (2018). Fetal heart rate short term variation during labor in relation to scalp blood lactate concentration. Acta Obstetricia et Gynecologica Scandinavica, 97(10), 1274-1280
Open this publication in new window or tab >>Fetal heart rate short term variation during labor in relation to scalp blood lactate concentration
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2018 (English)In: Acta Obstetricia et Gynecologica Scandinavica, ISSN 0001-6349, E-ISSN 1600-0412, Vol. 97, no 10, p. 1274-1280Article in journal (Refereed) Published
Abstract [en]

IntroductionFetal heart rate short term variation (STV) decreases with severe chronic hypoxia in the antenatal period. However, only limited research has been done on STV during labor. We have tested a novel algorithm for a valid baseline estimation and calculated STV. To explore the value of STV during labor, we compared STV with fetal scalp blood (FBS) lactate concentration, an early marker in the hypoxic process. Material and methodsSoftware was developed which estimates baseline frequency using a novel algorithm and thereby calculates STV according to Dawes and Redman in up to four 30-minute blocks prior to each FBS. Cardiotocography traces from 1070 women in labor who had had FBS performed on 2134 occasions were analyzed. ResultsIn acidemic cases (lactate >4.8mmol/L; Lactate Pro), median STV 30minutes prior to FBS was 7.10milliseconds compared with 6.09milliseconds in the preacidemic (4.2-4.8mmol/L) and 5.23milliseconds in the normal (<4.2mmol/L) groups (P<.05). There was a positive correlation between lactate and STV (rho=0.16-0.24; P<.05). Median lactate concentration in cases with STV <3.0milliseconds (n=160) was 2.3mmol/L. When 2 FBS were performed within 60minutes the change rate of lactate correlated to STV (rho=0.33; P<.001). Cases with increasing lactate concentration had a median STV of 5.29milliseconds vs 4.41milliseconds in those with decreasing lactate (P<.001). ConclusionsIn the early stages of intrapartum hypoxia, STV increases, contrary to findings regarding chronic hypoxia in the antenatal period. The increase in the adrenergic surge is a likely explanation.

Place, publisher, year, edition, pages
Wiley, 2018
Keywords
computer analysis, fetal heart rate monitoring, fetal scalp blood sampling, hypoxia, intrapartum, lactate, short-term variation
National Category
Obstetrics, Gynecology and Reproductive Medicine
Identifiers
urn:nbn:se:kth:diva-235432 (URN)10.1111/aogs.13390 (DOI)000444070900017 ()29799630 (PubMedID)2-s2.0-85052990496 (Scopus ID)
Note

QC 20180927

Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2018-10-22Bibliographically approved
Lu, K., Holzmann, M., Abtahi, F., Lindecrantz, K., Lindqvist, P. & Nordström, L. (2018). Fetal heart rate short term variation (STV) during labour in relation to early stages of hypoxia: An observational study. British Journal of Obstetrics and Gynecology, 125, 55-55
Open this publication in new window or tab >>Fetal heart rate short term variation (STV) during labour in relation to early stages of hypoxia: An observational study
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2018 (English)In: British Journal of Obstetrics and Gynecology, ISSN 1470-0328, E-ISSN 1471-0528, Vol. 125, p. 55-55Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Obstetrics, Gynecology and Reproductive Medicine
Identifiers
urn:nbn:se:kth:diva-227233 (URN)000430280500136 ()
Note

QC 20180514

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-05-14Bibliographically approved
Gyllencreutz, E., Lu, K., Lindecrantz, K., Lindqvist, P., Nordström, L., Holzmann, M. & Abtahi, F. (2018). Validation of a computerised algorithm to quantify fetal heart rate deceleration area: An observational study. British Journal of Obstetrics and Gynecology, 125, 54-54
Open this publication in new window or tab >>Validation of a computerised algorithm to quantify fetal heart rate deceleration area: An observational study
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2018 (English)In: British Journal of Obstetrics and Gynecology, ISSN 1470-0328, E-ISSN 1471-0528, Vol. 125, p. 54-54Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Medical Image Processing
Identifiers
urn:nbn:se:kth:diva-227232 (URN)000430280500135 ()
Note

QC 20180514

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-05-14Bibliographically approved
Gyllencreutz, E., Lu, K., Lindecrantz, K., Lindqvist, P. G., Nordström, L., Holzmann, M. & Abtahi, F. (2018). Validation of a computerized algorithm to quantify fetal heart rate deceleration area. Acta Obstetricia et Gynecologica Scandinavica, 97(9), 1137-1147
Open this publication in new window or tab >>Validation of a computerized algorithm to quantify fetal heart rate deceleration area
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2018 (English)In: Acta Obstetricia et Gynecologica Scandinavica, ISSN 0001-6349, E-ISSN 1600-0412, Vol. 97, no 9, p. 1137-1147Article in journal (Refereed) Published
Abstract [en]

IntroductionReliability in visual cardiotocography interpretation is unsatisfying, which has led to the development of computerized cardiotocography. Computerized analysis is well established for antenatal fetal surveillance but has yet not performed sufficiently during labor. We aimed to investigate the capacity of a new computerized algorithm compared with visual assessment in identifying intrapartum fetal heart rate baseline and decelerations. Material and methodsIn all, 312 intrapartum cardiotocography tracings with variable decelerations were analyzed by the computerized algorithm and visually examined by two observers, blinded to each other and the computer analysis. The width, depth and area of each deceleration was measured. Four cases (>100 variable decelerations) were subjected to in-depth detailed analysis. The outcome measures were bias in seconds (width), beats per minute (depth), and beats (area) between computer and observers using Bland-Altman analysis. Interobserver reliability was determined by calculating intraclass correlation and Spearman rank analysis. ResultsThe analysis (312 cases) showed excellent intraclass correlation (0.89-0.95) and very strong Spearman correlation (0.82-0.91). The detailed analysis of >100 decelerations in four cases revealed low bias between the computer and the two observers; width 1.4 and 1.4 seconds, depth 5.1 and 0.7 beats per minute, and area 0.1 and -1.7 beats. This was comparable to the bias between the two observers: 0.3 seconds (width), 4.4 beats per minute (depth) and 1.7 beats (area). The intraclass correlation was excellent (0.90-.98). ConclusionA novel computerized algorithm for intrapartum cardiotocography analysis is as accurate as gold standard visual assessment, with high correlation and low bias.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
Cardiotocography, computer-assisted signal processing, deceleration, fetal monitoring, interobserver variation
National Category
Obstetrics, Gynecology and Reproductive Medicine
Identifiers
urn:nbn:se:kth:diva-233267 (URN)10.1111/aogs.13370 (DOI)000440679900010 ()29768660 (PubMedID)2-s2.0-85051058017 (Scopus ID)
Note

QC 20180816

Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
Yang, L., Lu, K., Abtahi, F., Lindecrantz, K., Seoane, F., Forsman, M. & Eklund, J. (2017). A pilot study of using smart clothes for physicalworkload assessment. In: JOY AT WORK: . Paper presented at Conference Proceedings of Nordic Ergonomics Society 49th Annual Conference (pp. 169-170). Lund, Sweden
Open this publication in new window or tab >>A pilot study of using smart clothes for physicalworkload assessment
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2017 (English)In: JOY AT WORK, Lund, Sweden, 2017, p. 169-170Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Lund, Sweden: , 2017
Keywords
Energy expenditure estimation, pulmonary ventilation, heart rate.
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:kth:diva-227864 (URN)978-91-7753-152-4 (ISBN)
Conference
Conference Proceedings of Nordic Ergonomics Society 49th Annual Conference
Note

QC 20180614

Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-06-14Bibliographically approved
Gyllencreutz, E., Lu, K., Abtahi, F., Lindecrantz, K., Nordström, L., Lindqvist, P. & Holzmann, M. (2017). Characteristics of variable decelerations and prediction of fetal acidemia. Paper presented at 37th Annual Pregnancy Meeting of the Society-for-Maternal-Fetal-Medicine (SMFM), JAN 23-28, 2017, Las Vegas, NV. American Journal of Obstetrics and Gynecology, 216(1), S507-S507
Open this publication in new window or tab >>Characteristics of variable decelerations and prediction of fetal acidemia
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2017 (English)In: American Journal of Obstetrics and Gynecology, ISSN 0002-9378, E-ISSN 1097-6868, Vol. 216, no 1, p. S507-S507Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Obstetrics, Gynecology and Reproductive Medicine
Identifiers
urn:nbn:se:kth:diva-219522 (URN)000414256403203 ()
Conference
37th Annual Pregnancy Meeting of the Society-for-Maternal-Fetal-Medicine (SMFM), JAN 23-28, 2017, Las Vegas, NV
Note

QC 20171208

Available from: 2017-12-08 Created: 2017-12-08 Last updated: 2017-12-08Bibliographically approved
Wollmann, T., Abtahi, F., Eghdam, A., Seoane, F., Lindecrantz, K., Haag, M. & Koch, S. (2016). User-Centred Design and Usability Evaluation of a Heart Rate Variability Biofeedback Game. IEEE Access, 4, 5531-5539
Open this publication in new window or tab >>User-Centred Design and Usability Evaluation of a Heart Rate Variability Biofeedback Game
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2016 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 4, p. 5531-5539Article in journal (Refereed) Published
Abstract [en]

Background and objective: Reduced heart rate variability (HRV) is an indicatorof a malfunctioning autonomic nervous system. Resonant frequencybreathing is a potential non-invasive means of intervention for improvingthe balance of the autonomic nervous system and increasing HRV. However,such breathing exercises are regarded as boring and monotonous tasks.The use of gaming elements (gamification) or a full gaming experience is awell-recognised method for achieving higher motivation and engagement invarious tasks. However, there is limited documented knowledge on how todesign a game for breathing exercises. In particular, the influence of additionalinteractive elements on the main course of training has not yet beenexplored. In this study, we evaluated the satisfaction levels achieved usingdifferent game elements and how disruptive they were to the main task, i.e.,paced breathing training.

Methods: An Android flight game was developed with three game modes thatdiffer in the degrees of multitasking they require. Design, development and evaluation were conducted using a user-centred approach, including contextanalysis, the design of game principle mock-ups, the selection of game principlesthrough a survey, the design of the game mechanics and GUI mock-up,icon testing and the performance of a summative study through user questionnairesand interviews. A summative evaluation of the developed gamewas performed with 11 healthy participants (ages 40-67) in a controlled setting.Results: The results confirm the potential of video games for motivatingplayers to engage in HRV biofeedback training. The highest training performanceon the first try was achieved through pure visualisation rather thanin a multitasking mode. Players had higher motivation to play the morechallenging game and were more interested in long-term engagement.Conclusion: A framework for gamified HRV biofeedback research is presented.It has been shown that multitasking has considerable influence onHRV biofeedback and should be used with an adaptive challenge level.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Keywords
Autonomic nervous system;Biofeedback;Bioinformatics;Biological control systems;Games;Heart rate variability;Informatics;Multitasking;Patient rehabilitation;Resonant frequency;Consumer Health Informatics (CHI);Exergaming;Gamification for Health;Heart Rate Variability (HRV) Biofeedback;Patient Motivation;Usability
National Category
Human Computer Interaction Other Medical Engineering
Research subject
Medical Technology; Computer Science
Identifiers
urn:nbn:se:kth:diva-191359 (URN)10.1109/ACCESS.2016.2601882 (DOI)000395469000001 ()2-s2.0-85027047802 (Scopus ID)
Note

QC 20160907

Available from: 2016-08-30 Created: 2016-08-30 Last updated: 2018-09-19Bibliographically approved
Abtahi, F., Lu, K., Dizon, M., Johansson, M., Seoane, F. & Lindecrantz, K. (2015). Evaluating Atrial Fibrillation Detection Algorithm based on Heart Rate Variability analysis. In: Medicinteknikdagarna: . Paper presented at Medicinteknikdagarna 2015, Svensk förening för medicinsk teknik och fysik. Uppsala: Svensk förening för medicinsk teknik och fysik
Open this publication in new window or tab >>Evaluating Atrial Fibrillation Detection Algorithm based on Heart Rate Variability analysis
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2015 (English)In: Medicinteknikdagarna, Uppsala: Svensk förening för medicinsk teknik och fysik , 2015Conference paper, Poster (with or without abstract) (Refereed)
Place, publisher, year, edition, pages
Uppsala: Svensk förening för medicinsk teknik och fysik, 2015
Keywords
HRV Analysis, Heart Rate
National Category
Medical Engineering
Research subject
Människan i vården
Identifiers
urn:nbn:se:kth:diva-181861 (URN)
Conference
Medicinteknikdagarna 2015, Svensk förening för medicinsk teknik och fysik
Note

QCR 20160303

Available from: 2016-02-03 Created: 2016-02-05 Last updated: 2017-04-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4853-7731

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