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ABSTRACT: INTRODUCTION: The electrocardiogram (ECG) is a recording of the electrical activity of the heart. It is commonly used to non-invasively assess the cardiac activity of a patient. Since 1938, ECG data has been visualised as 12 scalar traces (known as the standard 12-lead ECG). Although this is known as the standard approach, there has been a myriad of alternative methods proposed to visualise ECG data. The purpose of this paper is to provide an overview of these methods and to introduce the field of ECG visualisation to early stage researchers. A scientific purpose is to consider the future of ECG visualisation within routine clinical practice. METHODS: This paper structures the different ECG visualisation methods using four categories, i.e. temporal, vectorial, spatial and interactive. Temporal methods present the data with respect to time, vectorial methods present data with respect to direction and magnitude, spatial methods present data in 2D or 3D space and interactive methods utilise interactive computing to facilitate efficient interrogation of ECG data at different levels of detail. CONCLUSION: Spatial visualisation has been around since its introduction by Waller and vector based visualisation has been around since the 1920s. Given these approaches have already been given the 'test of time', they are unlikely to be replaced as the standard in the near future. Instead of being replaced, the standard is more likely to be 'supplemented'. However, the design and presentation of these ECG visualisation supplements need to be universally standardised. Subsequent to the development of 'standardised supplements', as a requirement, they could then be integrated into all ECG machines. We recognise that without intuitive software and interactivity on mobile devices (e.g. tablet PCs), it is impractical to integrate the more advanced ECG visualisation methods into routine practice (i.e. epicardial mapping using an inverse solution).
Journal of electrocardiology 02/2013; · 1.08 Impact Factor
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ABSTRACT: BACKGROUND: Reduced lead systems utilizing patient-specific transformation weights have been reported to achieve superior estimates than those utilizing population-based transformation weights. We report upon the effects of ischemic-type electrocardiographic changes on the estimation performance of a reduced lead system when utilizing patient-specific transformation weights and population-based transformation weights. METHOD: A reduced lead system that used leads I, II, V2 and V5 to estimate leads V1, V3, V4, and V6 was investigated. Patient-specific transformation weights were developed on electrocardiograms containing no ischemic-type changes. Patient-specific and population-based transformations weights were assessed on 45 electrocardiograms with ischemic-type changes and 59 electrocardiograms without ischemic-type changes. RESULTS: For patient-specific transformation weights the estimation performance measured as median root mean squared error values (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 27.5 μV vs. 95.8 μV, P<.001; V3, 33.9 µV vs. 65.2 µV, P<.001; V4, 24.8 μV vs. 62.0 μV, P<.001; V6, 11.7 μV vs. 51.5 μV, P<.001). The median magnitude of ST-amplitude difference 60 ms after the J-point between patient-specific estimated leads and actual recorded leads (no ischemic-type changes vs. ischemic-type changes) was found to be (V1, 18.9 μV vs. 61.4 μV, P<.001; V3, 14.3 μV vs. 61.1 μV, P<.001; V4, 9.7 μV vs. 61.3 μV, P<.001; V6, 5.9 μV vs. 46.0 μV, P<.001). CONCLUSION: The estimation performance of patient-specific transformations weights can deteriorate when ischemic-type changes develop. Performance assessment of patient-specific transformation weights should be performed using electrocardiographic data that represent the monitoring situation for which the reduced lead system is targeted.
Journal of electrocardiology 09/2012; · 1.08 Impact Factor
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ABSTRACT: Personalization and context-aware applications have attracted increasing amounts of attention over recent years due to the emergence of pervasive computing applications. Nevertheless, it still remains a challenge to meet the needs of users while they are on the move. This paper introduces a novel approach for providing personalized, context-aware assistance services for users in mobile environments. Central to the approach is the use of ontological user profile modeling which captures various characteristics of a user in order to create a unique set of profile information. In addition, user profiles can adapt to changing user behavior, thus enabling services to respond to evolving user needs and preferences. We describe the overall system architecture of the proposed approach with special emphasis being placed on the user profile modelling and its expected utility based on a typical use case scenario, i.e., using a smart-phone to address the problem of the outdoor mobility of a person with Dementia. A prototype based on the Android OS is used to illustrate the application. The use of everyday technology for a real world problem highlights the potential and utility of our approach.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:6390-3.
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ABSTRACT: Walking is often cited as the best form of activity for persons over the age of 60. In this paper we outline the development and evaluation of a smart garment system that aims to monitor the wearer's wellbeing and activity regimes during walking activities. Functional requirements were ascertained using a combination of questionnaires and two workshops with a target cohort. The requirements were subsequently mapped onto current technologies as part of the technical design process. In this paper we outline the development and second round of evaluations of a prototype as part of a three-phase iterative development cycle. The evaluation was undertaken with 6 participants aged between 60 and 73 years of age. The results of the evaluation demonstrate the potential role that technology can play in the promotion of activity regimes for the older population.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:2100-3.
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ABSTRACT: Vectorcardiograpic (VCG) parameters can supplement the diagnostic information of the 12-lead electrocardiogram (ECG). Nevertheless, the VCG is seldom recorded in modern-day practice. A common approach today is to derive the Frank VCG from the standard 12-lead ECG (distal limb electrode positions). There is, to date no direct method that allows for a transformation from 12-lead ECGs with proximal limb electrode positions (Mason-Likar (ML) 12-lead ECG), to Frank VCGs. In this research, we develop such a transformation (ML2VCG) by means of multivariate linear regression on a training data set of 545 ML 12-lead ECGs and corresponding Frank VCGs that were both extracted surface potential maps (BSPMs). We compare the performance of the ML2VCG method against an alternative approach (2step method) that utilizes two existing transformations that are applied consecutively (ML 12-lead ECG to standard 12-lead ECG and subsequently to Frank VCG). We quantify the performance of ML2VCG and 2step on an unseen test dataset (181 ML 12-lead ECGs and corresponding Frank VCGs again extracted from BSPMs) through root mean squared error (RMSE) values, calculated over the QRST, between actual and transformed Frank leads. The ML2VCG transformation achieved a reduction of the median RMSE values for leads X (13.9µV; p<.001), Y (15.1µV; p<.001) and Z (2.6µV; p=.001) when compared to the 2step transformation. Our results show that the 2step method may not be optimal when transforming ML 12-lead ECGs to Frank VCGs. The utilization of the herein developed ML2VCG transformation should thus be considered when transforming ML 12-lead ECGs to Frank VCGs.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:677-80.
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Franka J M Meiland,
Ans I E Bouman,
Stefan Sävenstedt,
Sanne Bentvelzen,
Richard J Davies,
Maurice D Mulvenna, Chris D Nugent,
Ferial Moelaert,
Marike E Hettinga,
Johan E Bengtsson,
Rose-Marie Dröes
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ABSTRACT: To evaluate a newly developed integrated digital prosthetic, the COGKNOW Day Navigator (CDN), to support persons with mild dementia in their daily lives, with memory, social contacts, daily activities and safety.
A user participatory method was applied in the development process, which consisted of three iterative 1-year cycles with field tests in Amsterdam, Belfast and Luleå. In the successive cycles 16, 14 and 12 persons with dementia and their carers participated. Data on usability were collected by means of interviews, observations, questionnaires, logging and diaries. The CDN prototype consists of a touch screen, a mobile device, sensors and actuators.
The evaluation showed that persons with dementia and carers valued the CDN overall as user-friendly and useful. Conclusions regarding the effectiveness of the system in daily life were limited due to insufficient duration of the testing period caused by delays in development and some instability of the final prototype.
With the suggested adaptations, the CDN is expected to be a useful tool for supporting community-dwelling persons with mild dementia and their carers.
Aging and Mental Health 02/2012; 16(5):584-91. · 1.37 Impact Factor
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ABSTRACT: Accelerometers are widely accepted as practical wearable devices capable of measuring and assessing physical activity. These devices may, however, be subject to errors which could impact on their ability to acquire an accurate step count. A limited number of studies have examined the effects of body mass index (BMI) on the accuracy of accelerometers functioning as step counters. It has been suggested that BMI may not be the best indicator of adiposity. The aim of the present study was to assess the effects of BMI and abdominal volume on the accuracy of a step count obtained from a tri-axial accelerometer. Accelerometers were placed directly onto the skin at the chest, waist and lower back of 12 participants. Participants then walked on a motorized treadmill at 0.89 m/s and 1.34 m/s. Analysis of the results indicated that BMI and abdominal volume did not affect the accuracy of the step count obtained from accelerometers under any conditions. Walking speed, however, had a significant effect with step count accuracy decreasing at the slower speed.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2011; 2011:3656-9.
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ABSTRACT: The interoperability of the Electrocardiogram (ECG) between heterogeneous systems has been facilitated by not one, but a number of predefined open storage formats. To improve the techniques currently used, it is important to define the similarities and the differences between these ECG storage formats.
This paper presents a review of 9 formats used to store the ECG. Three of the predominant formats, namely, SCP-ECG, DICOM-ECG, and HL7 aECG are reviewed in detail along with the undertaking of a SWOT analysis. The remaining formats have been examined to a lesser extent as they are not as predominant in the literature.
This study suggests that a plethora of open ECG formats, all aiming to promote interoperability has the opposite effect of adding more complexity. This paper discusses whether a format supporting a variety of diagnostic modalities is more advantageous than a format that only supports the ECG. It is conclusive that a general purpose format such as DICOM solves more interoperability issues, however, no general purpose format currently exists that fulfils the requirements of all users. As a result, the healthcare industry has been bombarded with custom storage formats, i.e., a format for storing the resting ECG, a format for storing the ambulatory ECG, a format for storing the ECG in clinical trials, a format for storing ECG data on mobile devices etc. This study then examines which implementation method is more suited to encode ECG data, i.e. binary or XML. Binary encoding has been used in the past to store the ECG, however, unlike binary, XML files are human readable, searchable and provide a better form of semantics. Based on analysis within this work it is speculated that XML may overtake binary as the preferred implementation method for encoding ECG data since it has already made a huge impact in the healthcare industry.
It can be concluded that there is a wide range of vastly different techniques used to store the ECG. Although the specifications of these formats are openly available, neither has been internationally adopted to be used with all ECG machines. Therefore, there remains a lack of global interoperability of ECG information.
International Journal of Medical Informatics 07/2011; 80(10):681-97. · 2.41 Impact Factor
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ABSTRACT: The prevalence of Parkinson's disease (PD) is increasing due to an ageing population. It is an unpredictable disease which requires regular assessment and monitoring. Current techniques used to assess PD are subjective. Clinicians observe movements made by a patient and subsequently rate the level of severity of, for example tremor or slowness of movement. Within this work, we have developed and evaluated a prototype computer-based assessment tool capable of collecting information on the movement difficulties present in PD. Twenty participants took part in an assessment of the tool, 10 of whom were diagnosed with PD and 10 were without the disease. Following the usage of the tool, it was found that there was a significant difference (p = 0.038) in the speed of movement between the two groups. We envisage that this tool could have the potential to enable more objective clinical conclusions to be made.
Computer Methods in Biomechanics and Biomedical Engineering 05/2011; 15(10):1081-92. · 0.85 Impact Factor
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Toward Useful Services for Elderly and People with Disabilities - 9th International Conference on Smart Homes and Health Telematics, ICOST 2011, Montreal, Canada, June 20-22, 2011. Proceedings; 01/2011
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ERCIM News. 01/2011; 2011.
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IEEE Transactions on Information Technology in Biomedicine. 01/2011; 15:54-61.
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5th International Conference on Pervasive Computing Technologies for Healthcare, PervasiveHealth 2011, Dublin, Ireland, May 23-26, 2011; 01/2011
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IEEE Transactions on Information Technology in Biomedicine. 01/2011; 15:47-53.
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4th International Conference on Biomedical Engineering and Informatics, BMEI 2011, Shanghai, China, October 15-17, 2011; 01/2011
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Pervasive and Mobile Computing. 01/2011; 7:285-286.
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Technology and health care: official journal of the European Society for Engineering and Medicine 01/2011; 19(4):295-306.
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Toward Useful Services for Elderly and People with Disabilities - 9th International Conference on Smart Homes and Health Telematics, ICOST 2011, Montreal, Canada, June 20-22, 2011. Proceedings; 01/2011
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Advances in Computational Intelligence - 11th International Work-Conference on Artificial Neural Networks, IWANN 2011, Torremolinos-Málaga, Spain, June 8-10, 2011, Proceedings, Part II; 01/2011
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Ambient Intelligence - Software and Applications - 2nd International Symposium on Ambient Intelligence, ISAmI 2011, Salamanca, Spain, April 6-8, 2011; 01/2011
