Laramee CB, Lesperance L, Gause D
… +1 more, McLeod K
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959478
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Alarmed physiological monitors have become a standard part of the ICU. While the alarms generated by these monitors can be important indicators of an altered physiological condition, most are unhelpful to medical staff d...Alarmed physiological monitors have become a standard part of the ICU. While the alarms generated by these monitors can be important indicators of an altered physiological condition, most are unhelpful to medical staff due to a high incidence of false and clinically insignificant alarms. High numbers of false/insignificant alarms can lead to several adverse consequences such as increased patient anxiety,distraction of clinicians, and decreased efficiency in delivery of care. Furthermore, repeated false/insignificant alarms may increase the chance that healthcare providers ignore clinically significant alarms. In this paper we review the current state of intelligent alarm processing and describe an integrated systems methodology to extract clinically relevant information from physiological data. Such a method would aid significantly in the reduction of false alarms and provide nursing staff with a more reliable indicator of patient condition.
Shenoy KV, Santhanam G, Ryu SI
… +10 more, Afshar A, Yu BM, Gilja V, Linderman MD, Kalmar RS, Cunningham JP, Kemere CT, Batista AP, Churchland MM, Meng TH
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959477
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Neural prostheses have received considerable attention due to their potential to dramatically improve the quality of life of severely disabled patients. Cortically-controlled prostheses are able to translate neural activ...Neural prostheses have received considerable attention due to their potential to dramatically improve the quality of life of severely disabled patients. Cortically-controlled prostheses are able to translate neural activity from cerebral cortex into control signals for guiding computer cursors or prosthetic limbs. Non-invasive and invasive electrode techniques can be used to measure neural activity, with the latter promising considerably higher levels of performance and therefore functionality to patients. We review here some of our recent experimental and computational work aimed at establishing a principled design methodology to increase electrode-based cortical prosthesis performance to near theoretical limits. Studies discussed include translating unprecedentedly brief periods of "plan" activity into high information rate (6.5 bits/s)control signals, improving decode algorithms and optimizing visual target locations for further performance increases, and recording from chronically implanted arrays in freely behaving monkeys to characterize neuron stability. Taken together, these results should substantially increase the clinical viability of cortical prostheses.
Konofagou EE, Fung-Kee-Fung S, Luo J
… +1 more, Pernot M
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959476
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The heart is a mechanical pump that is electrically driven. We have previously shown that the contractility of the cardiac muscle can reliably be used in order to assess the extent of ischemia using myocardial elastograp...The heart is a mechanical pump that is electrically driven. We have previously shown that the contractility of the cardiac muscle can reliably be used in order to assess the extent of ischemia using myocardial elastography. Myocardial elastography estimates displacement and strain during the natural contraction of the myocardium using signal processing techniques on echocardiograms in order to assess the change in mechanical properties as a result of disease. In this paper, we showed that elastographic techniques can be used to estimate and image both the mechanics and electromechanics of normal and pathological hearts in vivo. In order to image the mechanics throughout the entire cardiac cycle, the minimum frame rate was determined to be on the order of 150 fps in a long-axis view and 300 fps in a short-axis view. The incremental and cumulative displacement and strains were measured and imaged for the characterization of normal function and differentiation from infracted myocardium. In order to image the electromechanical function, the incremental displacement was imaged inconsecutive cardiac cycles during end-systole in both dogs and humans. The contraction wave velocity in normal dogs was found to be twice higher than in normal humans and twice lower than in ischemic dogs. In conclusion, we have demonstrated that elastographic techniques can be used to detect and quantify the mechanics and electromechanics of the myocardium in vivo. Ongoing investigations entail assessment of myocardial elastography in characterizing and quantifying ischemia and infarction in vivo.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959475
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Articular cartilage is comprised of three histologic zones that exhibit different Young's moduli. In addition, with age and disease the moduli can be altered. Therefore,diagnosis of joint diseases can be accomplished by...Articular cartilage is comprised of three histologic zones that exhibit different Young's moduli. In addition, with age and disease the moduli can be altered. Therefore,diagnosis of joint diseases can be accomplished by detecting biomechanical properties of articular cartilage. In this report we investigate the feasibility of ultrasound elastography of bovine articular cartilage (n=5) employing instantaneous static compression using high-resolution (55MHz) ultrasound elastography in vitro as a potential arthroscopic technique. Elastograms were computed using cross-correlation technique and a gradient operator. The elastograms revealed near-zero strains within the samples, except at the articular surface and the interface between zones 1 and 2. The boundary conditions associated with the loading technique implemented herein that have to allow for a large acoustic window during imaging represent a fundamental challenge toward imparting local strains to the articular cartilage. Despite the complex boundary conditions, the feasibility of imaging strain within the cartilage during a sustained compression using elastographic techniques was demonstrated.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959473
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We introduce shape morphing approach to generate subject-specific finite element (FE) models. Different from the conventional approaches, our method generate individual (FE) model by applying spatial transformation to a...We introduce shape morphing approach to generate subject-specific finite element (FE) models. Different from the conventional approaches, our method generate individual (FE) model by applying spatial transformation to a reference model. It does not, therefore, require time-consuming works such as segmentation and mesh generation. The proposed method was applied to FE model generation of fingertips. The spatial trans-formation was computed using volume registration technique. The registration and the FE model morphing were carried out for two subjects. The morphing results showed good agreement in shape both for phalanxes and soft tissue.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959472
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This paper presents a fuzzy approach for contrast enhancement, based on two multi-scale transforms, namely wavelet and contourlet transforms. Separability and nondirectionality of conventional 2D wavelet transform, makes...This paper presents a fuzzy approach for contrast enhancement, based on two multi-scale transforms, namely wavelet and contourlet transforms. Separability and nondirectionality of conventional 2D wavelet transform, makes it unsuitable for sparsely representation of curve or line shaped image objects. On the other hand, the contourlet transform isa good alternative for this purpose. In this paper, coefficient enhancement, both in wavelet and contourlet spaces, is carried out by making use of simple fuzzy rules. These rules make the enhancement procedure more understandable and flexible. With this method, the knowledge and experience of the expert from the distribution of the coefficients can also be used in designing better enhancement functions. The proposed method is applied to both mentioned separable and nonseparable transforms. Implementation results demonstrate that this approach is very effective both in wavelet and contourlet spaces.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959471
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In medicine, the nature of an illness is often determined through behavioral or biological markers. The process of diagnosis becomes difficult when dealing with mental disorders since they rely primarily on behavioral ma...In medicine, the nature of an illness is often determined through behavioral or biological markers. The process of diagnosis becomes difficult when dealing with mental disorders since they rely primarily on behavioral markers. Schizophrenia is an example of a complex mental disorder that relies on aberrant behavior such as auditory hallucinations, dampening of emotions, paranoia, etc. This research is an attempt to determine a biological marker for schizophrenia through the use of functional magnetic resonance imaging (fMRI). In this paper, we propose a method of classification of schizophrenia and healthy controls, using a neural network approach and functional brain 'modes'estimated from resting state data using independent component analysis. A reliable technique for discriminating schizophrenia based upon fMRI would be a significant advance and may also provide additional information about the biological implications of mental illness.
Wu H, Xu G, Zhang S
… +3 more, Yang S, Li Y, Yan W
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959470
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The forward problem of the three dimensional electrical impedance tomography is presented in thorax model. Here potential distribution on the edge of the model measuring plan can be gotten by finite element method. The p...The forward problem of the three dimensional electrical impedance tomography is presented in thorax model. Here potential distribution on the edge of the model measuring plan can be gotten by finite element method. The potential distributions of inhaling and exhaling models are shown, and the opposite drive pattern are adopted with single drive current or multiple drive current. The forward problem is the base of the inverse problem in EIT research, and it is helpful to the monitor on thorax activities.
Okuno R, Yokoe M, Akazawa K
… +2 more, Abe K, Sakoda S
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959469
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The purpose of this study was to develop a finger taps acceleration measurement system for the quantitative diagnosis of Parkinson's disease. The system was composed of two 3-axis piezoelectric element accelerometers, a...The purpose of this study was to develop a finger taps acceleration measurement system for the quantitative diagnosis of Parkinson's disease. The system was composed of two 3-axis piezoelectric element accelerometers, a pair of touch sensors made of thin stainless steel sheets, an analog-digital(AD) converter and a personal computer (PC). Fingerstalls,with these sensors, were attached to subject's index finger and thumb. The acceleration and output of the touch sensors were recorded using the PC during the finger taps movements. Intervals between the single finger taps movements were calculated from the measured output of the touch sensors. Velocities during the single finger taps movements were calculated by integrating the measured acceleration. The amplitudes were calculated by integrating the velocities. The standard deviation of the single finger taps intervals, average of maximum single finger taps velocities and average of maximum single finger taps amplitudes were calculated from them. They were used as features for the quantitative diagnosis of Parkinson's disease. The developed system was used to conduct finger taps tests employing 27 normal subjects and 16 Parkinson's diseases subjects. The subjects were asked to execute continuous finger taps movement for 60 s. It was shown that the acceleration and output of the touch sensors could be measured and the features could be extracted.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959467
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Event-related potential (ERP) is a basic,non-invasive method of electrophysiological investigation. It can be used to assess aspects of human cognitive information processing. Recordings of ERPs from normal individuals h...Event-related potential (ERP) is a basic,non-invasive method of electrophysiological investigation. It can be used to assess aspects of human cognitive information processing. Recordings of ERPs from normal individuals have played an increasingly important role in our understanding of the mechanisms of attention. This paper focused on studies of specific cognitive subsystems such as visual pathway and attention with ERPs in different kinds of visual stimuli tasks using a 128-channel EEG system. The results have showed all potential amplitude of 19 electrodes varied largely with increasing stimuli task complexity and the P100, N200, P300 are elicited.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959466
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Due to the wide variety of equipment existing in clinical areas, there is an important question: which and how often electrical safety tests most be applied to the medical equipment. There are important differences about...Due to the wide variety of equipment existing in clinical areas, there is an important question: which and how often electrical safety tests most be applied to the medical equipment. There are important differences about the electrical safety, such as the electrical insulation or the hazard considering the connection between patient and electrical instrumentation. The objective of this work was to develop an Electrical Safety Priority Index for Medical Equipment(ESPIME) involving different classifications related with electrical safety, in order to provide a numeric code indicating the priority and frequency for applying the electrical safety tests to medical equipment. The index were applied to the medical equipment in critical care locations and the result,were used to defined which set of medical equipment would be the first for developing and applying electrical safety tests in a private hospital in Mexico City.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959465
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Providing health care effectively and efficiently involves putting together a great variety of resource inputs. Inputs or health technologies (HT) are human and physical resources - facilities and equipment, and consumab...Providing health care effectively and efficiently involves putting together a great variety of resource inputs. Inputs or health technologies (HT) are human and physical resources - facilities and equipment, and consumables including pharmaceuticals. In the complex health system environment, this wide range of technologies and related interventions produce an extraordinary array of different service outputs. The World Health Organization (WHO) embarked in mid-1990s on a major research and development initiative to design a methodology and tool that would allow for optimal, rational and systematic planning and management of healthcare technology interventions. These efforts culminated in the development of the Essential Healthcare Technology Package (EHTP),which has since been successfully applied in countries and by several WHO Technical Programs.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959464
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Patients with bilateral vestibular loss (BVL) of both central and peripheral origin experience multiple problems with balance and posture control, movement, and abnormal gait.Wicab, Inc. has developed the BrainPort balan...Patients with bilateral vestibular loss (BVL) of both central and peripheral origin experience multiple problems with balance and posture control, movement, and abnormal gait.Wicab, Inc. has developed the BrainPort balance device to transmit head position/orientation information normally provided by the vestibular system to the brain through a substitute sensory channel: electrotactile stimulation of the tongue. Head-orientation data (artificially sensed) serves as the input signal for the BrainPort balance device to control the movement of a small pattern of stimulation on the tongue that relates to head position in real-time. With training, the brain learns to appropriately interpret the information from the device and utilize it to function as it would with data from a normal-functioning natural sense. Ina total of 40 subjects trained with the BrainPort, 18 have been tested using standardized quantitative measurements of the treatment effects. A specialized set of exercises, testing, and training procedures has been developed that may serve as the course of intensive physical therapy with the BrainPort balance device. Our results demonstrate consistent positive and statistically significant balance rehabilitation effects independent of aging and etiology of balance deficit.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959463
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Ambulatory respiratory data was gathered using inductive lethysmography technology with synchronous ECG(LifeShirte , VivoMetrics, Ventura, CA) during a study to evaluate the effect of an anxiolytic on heart rate variabil...Ambulatory respiratory data was gathered using inductive lethysmography technology with synchronous ECG(LifeShirte , VivoMetrics, Ventura, CA) during a study to evaluate the effect of an anxiolytic on heart rate variability and respiratory pattern as indicators of anxiety state. Positive control (PCR; post-marketing, broadly prescribed anxiolytic)and placebo (PBO) data was included in the analysis. Tidal volume waveforms were the result of a weighted sum of the abdominal and rib cage IP bands according to the qualitative diagnostic calibration method. A breath detection algorithm was run to identify the beginning and end of inhalation in these waveforms. Several types of respiratory artifact are common with ambulatory, non-controlled recordings and a consistent and reliable means is necessary to identify and manage such artifacts. An automated approach was adopted to define a reliable breathing index for each breath that labels that breath as contaminated by artifact or not. The root mean square of successive differences (RMSSD) were computed on the tidal inspiratory volumes and total breath times for each epoch, both for all breaths and for only those breaths that were labeled as reliable. The results indicate that when a priori automated artifact detection is included, there is a significant linear decrease in both the volume and time indices for the PCR, whilst no significant differences were noted in the PBO group. Analyzing the data without prior marking of reliable breaths showed no significant results for either group. This study demonstrates the validity of ambulatory respiratory measurements as a means to assess anxiety and establishes the need to first identify reliable breathing periods prior to the analysis of ambulatory respiratory data.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959462
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In this paper a new ECG denoising scheme is proposed using a novel adaptive wavelet transform, named bionic wavelet transform (BWT), which had been first developed based on a model of the active auditory system. There ha...In this paper a new ECG denoising scheme is proposed using a novel adaptive wavelet transform, named bionic wavelet transform (BWT), which had been first developed based on a model of the active auditory system. There has been some outstanding features with the BWT such as nonlinearity, high sensitivity and frequency selectivity, concentrated energy distribution and its ability to reconstruct signal via inverse transform but the most distinguishing characteristic of BWT is that its resolution in the time-frequency domain can be adaptively adjusted not only by the signal frequency but also by the signal instantaneous amplitude and its first-order differential. Besides by optimizing the BWT parameters parallel to modifying a new threshold value, one can handle ECG denoising with results comparing to those of wavelet transform (WT). Preliminary tests of BWT application to ECG denoising were constructed on the signals of MIT-BIH database which showed high performance of noise reduction.
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959461
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A common practice in microarray analysis is to transform the microarray raw data (light intensity) by a logarithmic transformation, and the justification for this transformation is to make the distribution more symmetric...A common practice in microarray analysis is to transform the microarray raw data (light intensity) by a logarithmic transformation, and the justification for this transformation is to make the distribution more symmetric and Gaussian-like. Since this transformation is not universally practiced in all microarray analysis, we examined whether the discrepancy of this treatment of raw data affect the "high level"analysis result. In particular, whether the differentially ex-pressed genes as obtained by t-test, regularized t-test, or logistic regression have altered rank orders due to presence or absence of the transformation. We show that as much as 20%-40% of significant genes are "discordant" (significant only in one form of the data and not in both), depending on the test being used and the threshold value for claiming significance. The t-test is more likely to be affected by logarithmic transformation than logistic regression, and regularized t-test more affected than t-test. On the other hand, the very top ranking genes (e.g. upto top 20-50 genes, depending on the test) are not affected by the logarithmic transformation.
Cordovez JM, Clausen C, Moore LC
… +1 more, Solomon IC
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959460
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In this paper, we present a mathematic model designed to identify potential mechanisms responsible for the observed differences in pHi recovery in CO(2)-chemosensitive versus non-chemosensitive cells. The model suggests...In this paper, we present a mathematic model designed to identify potential mechanisms responsible for the observed differences in pHi recovery in CO(2)-chemosensitive versus non-chemosensitive cells. The model suggests that differences in pHi regulation may be dependent upon differences in the activation set-point of the internal modifier site of the Na(+)/H(+) exchanger (NHE).
Fan Y, Rao H, Giannetta J
… +4 more, Hurt H, Wang J, Davatzikos C, Shen D
Conf Proc IEEE Eng Med Biol Soc
· 2006 · PMID 17959459
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A number of neurological diseases are associated with structural and functional alterations in the brain. This paper presents a method of using both structural and functional MR images for brain disease diagnosis, by mac...A number of neurological diseases are associated with structural and functional alterations in the brain. This paper presents a method of using both structural and functional MR images for brain disease diagnosis, by machine learning and high-dimensional template warping. First, a high-dimensional template warping technique is used to complete morphological and functional representation for each individual brain in a template space, within a mass preserving framework. Then, statistical regional features are extracted to reduce the dimensionality of morphological and functional representation , as well as to achieve the robustness to registration errors and inter-subject variations. Finally, the most discriminative regional features are selected by a hybrid feature method for brain classification, using a nonlinear support vector machine. The proposed method has been applied to classifying the brain images of prenatally cocaine-exposed young adults from those of socioeconomically matched controls, resulting in 91.8% correct classification rate using a leave-one-out cross-validation. Comparison results show the effectiveness of our method and also the importance of simultaneously using both structural and functional images for brain classification.