Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference最新文献

Suitable spatial filters were explored for inverse estimation of cortical potential imaging from the scalp electroencephalogram. The effects of incorporating signal and noise covariance into inverse procedures were examined by computer simulations and experimental study. The parametric Wiener filter (PWF) was applied to an inhomogeneous three-sphere head model under various signal and noise conditions. We also examined estimation methods for the signal covariance in PWF. The present simulation results suggest that the PWF with modified matrix transformation method has better performance. The proposed methods were applied to self-paced movement-related potentials In order to identify the anatomic substrate locations of neural generators in realistic head model. The proposed methods demonstrated that the contralateral premotor cortex was preponderantly activated In relation to movement performance.

The introduction of distributed ECG interpretation is currently limited by the computational capacity of a battery-operated wearable recorder. The relations between human experts in cardiology are generalized in this paper and considered as a pattern of co-operation between computerized interpretation centers. Studying the cardiologist's practice we found out that during the years the range of family doctors skills, their adaptations to the patient-specific needs and their communication with the regional experts were optimized. Extrapolation of this approach to the artificial networks assumes that only selected and commutable basic interpretation routines are implemented in a remote recorder limiting its costs, increasing the autonomy time and adaptability. While most of cases are resolved on local level, the complicated but not very frequent events are reported directly to the interpretive center, for automated or human-assisted interpretation. Such architecture, derived from natural task sharing, is believed to fulfil all the diagnostic requirements with minimum involvement of complicated equipment and at minimum costs of data transmission.

This paper presents an initial formal review of the suitability of currently available actuation technologies for use in fully implantable medical devices, with a focus on applications requiring linear motion. Examples of such applications are a mechatronic hydrocephalus shunt and implantable insulin pumps. Some general basic requirements for fully implantable devices are discussed, followed by an overview of potential actuators. Possible design concepts are presented for electromagnetic and shape memory technologies, including a comparison of their respective pros and cons. Methods of modeling and analysis are given to aid early decision-making processes for general design applications. Finally, other more complicated but attractive actuation possibilities are discussed.

Due to the large transmural variation in transmembrane potential following the application of strong electric shocks, it is thought that fluorescent photon scattering from depth plays a significant role in optical signal modulation at shock-end. For the first time, a model of photon scattering is used to accurately synthesize fluorescent signals over the irregular geometry of the rabbit ventricles following the application of such strong shocks. A bidomain representation of electrical activity is combined with finite element solutions to the photon diffusion equation, simulating both the excitation and emission processes, over an anatomically-based model of rabbit ventricular geometry and fiber orientation. Photon scattering from within a 3D volume beneath the epicardial optical recording site is shown to transduce differences in transmembrane potential within this volume through the myocardial wall. This leads directly to a significantly modulated optical signal response with respect to that predicted by the bidomain simulations, distorting epicardial virtual electrode polarization produced at shock-end. Furthermore, we show that this degree of distortion is very sensitive to the optical properties of the tissue, an important variable to consider during experimental mapping set-ups. These findings provide an essential first-step in aiding the interpretation of experimental optical mapping recordings following strong defibrillation shocks.

VALUE is a randomized controlled trial to evaluate the impact of a home telehealth program on the ability of frail elderly individuals to remain living independently in their own home as their self-care abilities decline. VALUE uses broadband access to provide virtual visits with a home care nurse, a Web portal for ordering assisted living services, physiological monitoring, and access to the Internet. Subjects were able to use the VALUE program technology without difficulty after a brief instruction session with the nurse.

A method is reported to accurately and precisely control temperature of a solution sample to investigate non-thermal effects of radio frequency radiation (RFR) on pharmaceuticals. This method utilizes a transverse electromagnetic (TEM) cell connected in series with a radiation source. The temperature of a sample under study, within the TEM cell, is regulated using a combination of a fiber-optic thermometer and thermo-electric cooler. It is shown that the sample temperature can be accurately controlled and maintained even under conditions where the RFR can increase the sample temperature via thermal mode. This methodology provides a well-controlled approach to investigate the non-thermal effects of RFR for a range of incident power intensities and frequencies and initial sample temperatures.

Speech transients are important cues for identifying and discriminating speech sounds. Yoo et al. and Tantibundhit et al. were successful in identifying speech transients and, emphasizing them, improving the intelligibility of speech in noise. However, their methods are computationally intensive and unsuitable for real-time applications. This paper presents a method to identify and emphasize speech transients that combines subband decomposition by the wavelet packet transform with variable frame rate (VFR) analysis and unvoiced consonant detection. The VFR analysis is applied to each wavelet packet to define a transitivity function that describes the extent to which the wavelet coefficients of that packet are changing. Unvoiced consonant detection is used to identify unvoiced consonant intervals and the transitivity function is amplified during these intervals. The wavelet coefficients are multiplied by the transitivity function for that packet, amplifying the coefficients localized at times when they are changing and attenuating coefficients at times when they are steady. Inverse transform of the modified wavelet packet coefficients produces a signal corresponding to speech transients similar to the transients identified by Yoo et al. and Tantibundhit et al. A preliminary implementation of the algorithm runs more efficiently.

A novel algorithm for performing registration of dynamic contrast-enhanced (DCE) MRI data of the breast is presented. It is based on an algorithm known as iterated dynamic programming originally devised to solve the stereo matching problem. Using artificially distorted DCE-MRI breast images it is shown that the proposed algorithm is able to correct for movement and distortions over a larger range than is likely to occur during routine clinical examination. In addition, using a clinical DCE-MRI data set with an expertly labeled suspicious region, it is shown that the proposed algorithm significantly reduces the variability of the enhancement curves at the pixel level yielding more pronounced uptake and washout phases.

The design of metal microelectrodes that produce minimal damage to tissue and can successfully record from and stimulate targeted neural structures necessitates a thorough understanding of the electrical phenomena generated in the tissue surrounding the electrodes. Computational modeling has been a primary strategy used to study these phenomena, and the Finite Element Method has proven to be a powerful approach. Much research has been directed toward the development of models for electrode recording and stimulation, but very few models reported in the literature thus far incorporate the effects of the electrode-electrolyte interface, which can be a source of very high impedance, and thus likely a key component of the system. To explore the effects that the electrode-electrolyte interface has upon the electric potential and current density surrounding metal microelectrodes, simulations of electrode-saline systems in which the electrodes were driven at AC potentials ranging from 10 mV to 500 mV and frequencies of 100 Hz to 10 kHz have been performed using the Finite Element Method. Solutions obtained using the thin layer approximation for the electrode-electrolyte interface was compared with those generated using a thin uniform layer, a representation that has previously appeared in the literature. Solutions using these two methods were similar in the linear regime of the interface however, the thin layer approximation has important advantages over its competitor including ease of application and low computational cost.

In the last decade, the possibility to noninvasively estimate cortical activity has been highlighted by the application of the techniques known as high resolution EEG. These techniques include a subject's multi-compartment head model (scalp, skull, dura mater, cortex) constructed from individual magnetic resonance images, multi-dipole source model, and regularized linear inverse source estimates of cortical current density. The aim of this paper is to demonstrate that the use of cortical activity estimated from noninvasive EEG recordings of motor imagery is useful in the context of a brain computer interface as compared with others scalp spatial filters usually used on-line.