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N. Shanmathi  M. Jagannath 《IRBM》2018,39(5):359-367

Background

Remote health monitoring plays a major role in handling the critical situation of patients and avoiding death and also enhancing the quality of healthcare services. The effective real time monitoring with accurate decision has to be made in advance with the help of decision making system by continuously acquiring biosignals.

Objectives

The main objective was to outline the research on remote patient health monitoring system that constitutes the multimodal biosignal acquisition system, thereby providing multi-label classification and clinical decision support system (CDSS).

Methods and results

A review was conducted with search terms such as multi-label classification, clinical decision support system, context-awareness and remote health monitoring. The study criteria included the randomized clinical trials evaluating the impact of efficient remote health monitoring system which incorporates CDSS for context-awareness systems by correlating several vital signs. From the total papers (n=52) which were included in the review, the major concentration of the review is multi-label classification (n=21, 40%). Further, this article included the review in context-awareness methods (n=5, 10%), clinical decision support systems (n=12, 23%), different means of biosignal acquisition and pre-processing (n=5, 10%), databases and software techniques for developing learning algorithms (n=3, 6%) and from general category (n=6, 12%). Several studies were effectively included which provides faster diagnosis for critically ill-patients. It is decisive for the critically ill-patients to be treated at the right time with proper and effective treatment which can be done efficiently using the CDSS and multi-label classification. The disease labels are classified as single and multi-labels where multi-label classification includes the disease labels for the correlated multiple vital signs and single label classification includes disease labels for individual vital signs. Further, on developing the logical learning model using multi-label classification, decision support system can be enhanced using context-awareness methods to predict the future vital signs, thereby providing an alert to the patients or doctors to take necessary actions.

Conclusion

The proposed system includes the model that provides the correlations of several biosignals like electrocardiogram (ECG), peripheral capillary oxygen saturation (SPO2), body temperature and heartbeat, thereby identifying the critical situations and making the decisions using CDSS that helps in taking the necessary clinical interventions.  相似文献   

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Purpose

Today's orthotics should be designed to apply the external orthosis moment to the knee joint solely during the stance phase instead of the entire gait cycle. The aim of this study was to validate the reliability of a simple device for measuring forces at the leg–orthosis interface and describe the behavior of an innovating dynamic unloader knee brace built to interrupt its mechanical action during large knee flexion (swing phase of gait).

Methods

A compression testing machine was used to apply known (standard) forces to the device (modeled forces) and the results were compared.

Results

The low absolute mean bias (4%), the narrow agreement limits associated with the Bland and Altman analysis as well as the significant linear correlation (r=0.99; p<0.001) validate the agreement between standard and modeled forces. Likewise, the low standard error of measurement between trials (1.3%) and the intraclass correlation coefficient (1.00) reflect high test-retest reliability.

Conclusion

These results demonstrate the validity of the proposed device for measuring constraints induced by the dynamic unloader knee brace. An example of an application is provided through an orthosis moment calculation using kinematic data, which reveal a changeable mechanical action, necessary to improve comfort resulting in potentially better compliance.  相似文献   

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Y. Matanga  K. Djouani  A. Kurien 《IRBM》2018,39(5):324-333

Context

Sensorimotor rhythms (SMR) have been the neuronal phenomena of choice in non-invasive EEG-based endogenous brain computer interfaces (BCIs) for more than two decades and SMR-based BCIs have achieved the highest degree of freedom control so far. Nevertheless, they are subject to long periods of training prior to attaining a satisfactory level of control requiring users to learn to modulate their rhythms. The goal of this work is to analyse this problem, discuss the causes of the slow rise in performance and provide recommendations on alternative solutions to quicken control attainment.

Methods

The study has been conducted by both theoretical and empirical analysis. A theoretical model has been developed that explains the principle operation of SMR-based BCIs focusing on major performance contributors respectively the user, periodic feature selection and the translation model thus contrasting user adaptation and machine learning. Five able-bodied subjects (age: 26±2.55) participated in six sessions of online computer cursor control experiments over three weeks to evaluate control attainment performances and gather data for statistical analysis (~1152 trials per subject). Correlation (r2) between user control features and target position over sessions was assessed as an estimate of neural adaptation and the predictive power of the translation algorithm (10 × 10 fold cross-validation) was calculated over sessions as an estimate of machine adaptation. Auxiliary performance metrics were evaluated.

Results

Features-target correlation increased over sessions, while at the same time the predictive accuracy (R2) of the translation model remained averagely steady and very low (Rbest2=0.04) demonstrating continuous user adaptation and low model predictive accuracy. Periodic feature selection was theoretically discussed to be very instrumental and its relevance was empirically illustrated.

Conclusions

The study concludes that the slow control attainment in SMR-based BCIs is due to its reliance on user training (neural adaptation) which is adaptive but too slow in the context of SMR modulations and due to the weak decoding of the neuronal phenomenon utilised by the user. As a recommendation, the optimality of the feature selection algorithm could be looked at to guarantee the use of the most relevant features. However and most importantly the predictive power of the translation model should be significantly improved in order to quicken control attainment as thereafter the control attainment effort could be shifted from neural adaptation to machine learning.  相似文献   

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Objective

The aims of this study, to investigate the interaction among heart rate variability (HRV), respiratory, systolic arterial blood pressure variability (SABPV) and systolic arterial pressure interval variability (APIV) signals for understanding of cardiovascular control.

Methods

In this study, three methods referred as adaptive continuous Morlet wavelet transform (ADCMWT), adaptive Stockwell transform (ADST) and adaptive modified Stockwell transform (ADMST) was used to assess the accuracy (AC) of time-varying spectral coherence (TVSC). The adaptation of these estimators was based on maximum energy concentration measurement. The capability to correct temporal localization of time–frequency regions was validated on synthetic time series data modeled as dynamic characteristics of cardiovascular signals.

Results

The results on synthetic simulated data show that the ADCMWT method allows for the temporal localization of the time–frequency regions with higher accuracy (AC > 96.074% for SNR ≥ 0 dB), compared to ADST (AC > 90.71% for SNR ≥ 0 dB) and ADMST (AC > 84.45% for SNR ≥ 5 dB). Further, the ADCMWT was applied to real cardiovascular data obtained from Fantasia standard data base and grouped as, 8 young subjects (4M + 4F, age range 23–32) and 8 elderly subjects (4M + 4F, age range 70–82) for estimating the TVSC in low frequency (LF) band (0.04 Hz–0.15 Hz) and high frequency (HF) band (0.15 Hz–0.4 Hz) of HRV spectrum. The global result depict that the median value of interquartile range of coherency between HRV-SABPV and HRV-APIV signals in LF and HF band were significantly (p=0.00001) lower in elderly group subjects compared to young group subjects. The coupling between HRV-Respiratory signals in LF band was not significantly affected with the aging of healthy subjects. However, this coupling in HF band significantly reduced in elderly compare to young group subjects (p=0.0125).

Conclusion

The comparative study shows that the time-varying spectra and accurate localization of coupling between two physiological signals can be affected by energy concentration. The ADCMWT at w0=6, could be an alternative, possibly more suitable and highly accurate method for assessment and detection of time varying spectral and coherence components of cardiovascular time series.  相似文献   

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In this paper, we quantify the extent to which shoulder orientation, upper-arm electromyography (EMG), and forearm EMG are predictors of distal arm joint angles during reaching in eight subjects without disability as well as three subjects with a unilateral transhumeral amputation and targeted reinnervation. Prior studies have shown that shoulder orientation and upper-arm EMG, taken separately, are predictors of both elbow flexion/extension and forearm pronation/supination. We show that, for eight subjects without disability, shoulder orientation and upper-arm EMG together are a significantly better predictor of both elbow flexion/extension during unilateral (R2=0.72) and mirrored bilateral (R2=0.72) reaches and of forearm pronation/supination during unilateral (R2=0.77) and mirrored bilateral (R2=0.70) reaches. We also show that adding forearm EMG further improves the prediction of forearm pronation/supination during unilateral (R2=0.82) and mirrored bilateral (R2=0.75) reaches. In principle, these results provide the basis for choosing inputs for control of transhumeral prostheses, both by subjects with targeted motor reinnervation (when forearm EMG is available) and by subjects without target motor reinnervation (when forearm EMG is not available). In particular, we confirm that shoulder orientation and upper-arm EMG together best predict elbow flexion/extension (R2=0.72) for three subjects with unilateral transhumeral amputations and targeted motor reinnervation. However, shoulder orientation alone best predicts forearm pronation/supination (R2=0.88) for these subjects, a contradictory result that merits further study.  相似文献   

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We compare two constitutive models proposed to model the elastinous constituents of an artery. Holzapfel and Weizsäcker [1998. Biomechanical behavior of the arterial wall and its numerical characterization. Comput. Biol. Med. 28, 377–392] attribute a neo-Hookean response, i.e. Ψ=c(I1-3)), to the elastin whilst Zulliger et al. [2004a. A strain energy function for arteries accounting for wall composition and structure. J. Biomech. 37, 989–1000] propose Ψ=c(I1-3)3/2. We analyse these constitutive models for two specific cases: (i) uniaxial extension of an elastinous sheet; (ii) inflation of a cylindrical elastinous membrane. For case (i) we illustrate the functional relationships between: (a) the Cauchy stress (CS) and the Green–Lagrange (GL) strain; (b) the tangent modulus (gradient of the CS–GL strain curve) and linearised strain. The predicted mechanical responses are compared with recent uniaxial extension tests on elastin [Gundiah, N., Ratcliffe, M.B., Pruitt, L.A., 2007. Determination of strain energy function for arterial elastin: experiments using histology and mechanical tests. J. Biomech. 40, 586–594; Lillie, M.A., Gosline, J.M., 2007a. Limits to the durability of arterial elastic tissue. Biomaterials 28, 2021–2031; 2007b. Mechanical properties of elastin along the thoracic aorta in the pig. J. Biomech. 40, 2214–2221]. The neo-Hookean model accurately predicts the mechanical response of a single elastin fibre. However, it is unable to accurately capture the mechanical response of arterial elastin, e.g. the initial toe region of arterial elastin (if it exists) or the gradual increase in modulus of arterial elastin that occurs as it is stretched. The alternative constitutive model (n=32) yields a nonlinear mechanical response that departs from recent uniaxial test data mentioned above, for the same stretch range. For case (ii) we illustrate the pressure–circumferential stretch relationships and the gradients of the pressure–circumferential stretch curves: significant qualitative differences are observed. For the neo-Hookean model, the gradient decreases rapidly to zero, however, for n=32, the gradient decreases more gradually to a constant value. We conclude that whilst the neo-Hookean model has limitations, it appears to capture more accurately the mechanical response of elastin.  相似文献   

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