Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Automatism”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed1994

Manual and automatic gallstone dissolution with methyl tert-butyl ether.

The aim of the study was to establish the efficiency of cholesterol gallstone dissolution with methyl tert-butyl ether in a large group of patients and to compare the results of patients treated manually by a nurse or using an automatic pump. Gallbladder puncture was successful in 228 patients (99%). After 9 hr, 211 patients (91%) were stone-free; 144 (68%) of them left the hospital on the fourth day. In radiolucent stones not isodense with bile on a CT scan, dissolution rate decreased by 10%, treatment time was prolonged by 40%. Forty-two of the 228 patients were selected for the hand-syringed group, 42 patients, who matched these patients in stone size and number, were treated with an automatic pump (Baxter). Stone burden in matched pairs was comparable. Stones dissolved in 96% of the patients in both groups. Sludge remained in the gallbladder in 52% after manual treatment and 60% after automatic therapy. Side effects were identical in both groups. None of the side effects were pump-related. Automatic therapy reduced the time needed by the nurse to treat each patient by 70%.

Catheterization↗
PubMed2005

Automatic analysis of immunocytochemically stained tissue samples.

An automatic colour image segmentation and cell counting software system has been developed for immunocytochemical analysis of stained tissue samples. The system was designed to count the total number of positive and negative cells in tissue samples treated with cytokine DNA probes from pigs naturally parasitised with Taenia solium metacestodes, using in situ hybridisation. A reaction index was calculated as the ratio of the number of cells with a positive reaction to the total number of cells (positives plus negatives) for each of five different probes. The objectives of automatic counting were to improve the reproducibility of the analysis and reduce the processing time of large image batches. A fast KNN classifier was used for colour segmentation. Watershed segmentation combined with edge detection was used to isolate individual cells that were then automatically labelled, using the results of the corresponding colour segmented image. Validation was performed on 122 non-training digital images with a total of 1069 positive cells and 1459 negative cells, with the following results: a mean true positive rate of 90.2% for positive cells and a mean true positive rate of 85.4% for negative cells. The corresponding mean false positive rates were 9.6% and 6.6%. The mean reaction index error of the automatic analysis was 5.35%. The processing of each digital image took 10 s on a Pentium IV PC.

Animals↗
PubMed1991

Validated method for automatic detection of lung sound crackles.

Crackling lung sounds are associated with many pulmonary diseases. Their occurrence reflects the quality and the severity of the disease. An automatic method for crackle detection is developed, based on analysing the spectral stationarity of the lung sound. The method is validated by studying the crackles of 20 adult patients; 10 with fibrosing alveolitis (FA) and 10 with bronchiectasis (BE). The number of crackles detected by the automatic method in inspiratory cycles is compared to the number of crackles counted from time-expanded waveforms by two expert observers. The total number of inspiratory cycles studied is 117 and that of crackles 1064. The method has a sensitivity of 89 per cent and a positive predictivity of 88 per cent for patients with FA, and 80 per cent and 83 per cent respectively, for patients with BE. The linear correlation coefficients between the numbers of crackles counted by the automatic method and by the observers is 0.86 (p less than 0.001) for the patients with FA and 0.93 (p less than 0.001) for the patients with BE. The values refer to whole inspiratory cycles. The new automatic method seems reliable enough for clinical and scientific purposes. It enables a rapid and objective analysis of large materials with crackling lung sounds.

Aged↗
PubMed1999

Automatic detection of the electrocardiogram T-wave end.

Various methods for automatic electrocardiogram T-wave detection and Q-T interval assessment have been developed. Most of them use threshold level crossing. Comparisons with observer detection were performed due to the lack of objective measurement methods. This study followed the same approach. Observer assessments were performed on 43 various T-wave shapes recorded: (i) with 100 mm s-1 equivalent paper speed and 0.5 mV cm-1 sensitivity; and (ii) with 160 mm s-1 paper speed and vertical scaling ranging from 0.07 to 0.02 mV cm-1, depending on the T-wave amplitude. An automatic detection algorithm was developed by adequate selection of the T-end search interval, improved T-wave peak detection and computation of the angle between two 10 ms long adjacent segments along the search interval. The algorithm avoids the use of baseline crossing and direct signal differentiation. It performs well in cases of biphasic and/or complex T-wave shapes. Mean differences with respect to observer data are 13.5 ms for the higher gain/speed records and 14.7 ms for the lower gain/speed records. The algorithm was tested with 254 various T-wave shapes. Comparisons with two other algorithms are presented. The lack of a 'gold standard' for the T-end detection, especially if small waves occur around it, impeded adequate interobserver assessment and evaluation of automatic methods. It is speculated that a simultaneous presentation of normal and high-gain records might turn more attention to this problem. Automatic detection methods are in fact faced with 'high-gain' data, as high-resolution analogue-to-digital conversion is already widely used.

Algorithms↗
PubMed1997

An easy and reproducible semi-automatic method for the evaluation of 99mTc-galactosyl human serum albumin.

99mTc-galactosyl human serum albumin (99mTc-GSA) scintigraphy is a new method for evaluating liver function. This scintigraphy is useful for evaluating the severity of liver diseases. The indices evaluating hepatic function include the receptor index (LHL15) and the index of blood clearance (HH15). These indices are calculated on the basis of the regions of interest (ROIs) for both whole liver and heart, and are susceptible to the ROIs over heart and liver. At present, there is no standard method for determining ROIs. We attempted to establish a standard method which shall not be subject to inter and/or intra operator variation. A computer program to determine heart and liver ROIs semi-automatically was developed. Ten patients (12 instances) were studied with 99mTc-GSA, and HH15 and LHL15 were calculated on the basis of the ROIs obtained manually and semi-automatically by 3 different operators independently. Blood sampling and gamma-counting yielded blood clearance data. The ICG R15 was compared with each index in 34 patients. The time needed for ROI determination was reduced from 2-3 minutes for the manual method to 0.5-0.8 minutes for the semi-automatic method. The % coefficients of variation (% CVs) of HH15 and LHL15 were improved in the order manual-inter observer (M-inter), manual-intra observer (M-intra) and semi-automated-inter observer (SA-inter); % CVs of HH15 were 2.26% for M-inter, 1.55% for M-intra and 0.07% for SA-inter, and % CVs of LHL15 were 2.29% for M-inter, 0.46% for M-intra and 0.07% for SA-inter. The correlation of HH15 and LHL15 among M-inter, M-intra and SA-inter was good. Comparison of indices obtained by manual and semi-automatic methods with blood clearance data obtained by blood sampling and gamma-counting showed good correlations and no significant differences. The comparison with ICG R15 showed that HH15 and LHL15 by the semi-automated method gave better correlation that that by the manual method. A newly developed semi-automated method improved data processing time and deviation of indices in 99mTc-GSA studies. This method should substitute for manual ROI determination.

Automation↗
PubMed2001

[Sensor-induced rate adaptation: sensor systems and tuning. Manual versus automatic tuning].

BACKGROUND: Rate adaptive stimulation represents an established therapeutic option in the management of cardiac rhythm disturbance. To realize a physiologic heart rate in patients with chronotopic incompetence several different sensor systems were developed. Due to the requirements of a physiologic pacemaker with all algorithms and therapeutic functions complex pacemaker systems were created. The realization of an automatic rate optimization was given by self adjusting algorithm or new sensor systems (closed loop systems). Comparing data respecting automatic vs manual sensor adjustment are not present. The automatic sensor adjustment was examined only in small patient groups. CONCLUSION: This studies indicated that most patients could be adjusted by the automatic function. Nevertheless, out of technical reasons a small group of patients could not be adjusted. The verification of the correct individual rate response in all patients treated with rate response pacemakers belongs to the physicians obligation.

Adult↗
PubMed2001

Retrograde facilitation of memory by triazolam: effects on automatic processes.

RATIONALE: Retrieval processes have been implicated as a potential mechanism by which benzodiazepines can produce retrograde memory facilitation. OBJECTIVES: This study tested the degree to which benzodiazepine-induced retrograde facilitation of memory was due to an enhancement of automatic retrieval processes. METHODS: Forty healthy adults were randomly assigned to one of three dose conditions (double-blind), under which they received 0.0 mg (placebo), 0.125 mg, or 0.25 mg of the short-acting benzodiazepine triazolam (Halcion). Subjects studied a list of words just prior to dose administration. One hour after dose administration, subjects performed a word-stem completion task which tested their retrieval of the studied words. A process-dissociation procedure was used to estimate the degree to which retrieval was under the influence of memory processes that were automatic (i.e., unintentional) versus controlled (i.e., intentional). RESULTS: Subjects who received active doses of triazolam displayed a greater probability of using studied words as stem completions. Estimates of memory processes showed a greater influence of automatic influences during memory retrieval under triazolam doses. CONCLUSIONS: The findings indicate that retrograde memory facilitation following benzodiazepine administration does not necessarily reflect an improved ability to intentionally retrieve information but could instead reflect increased responsiveness to cues that automatically elicit retrieval of pre-drug information.

Adolescent↗
PubMed1998

Semi-automatic segmentation of gated blood pool emission tomographic images by watersheds:application to the determination of right and left ejection fractions.

Tomographic multi-gated blood pool scintigraphy (TMUGA) is a widely available method which permits simultaneous assessment of right and left ventricular ejection fractions. However, the widespread clinical use of this technique is impeded by the lack of segmentation methods dedicated to an automatic analysis of ventricular activities. In this study we evaluated how a watershed algorithm succeeds in providing semi-automatic segmentation of ventricular activities in order to measure right and left ejection fractions by TMUGA. The left ejection fractions of 30 patients were evaluated both with TMUGA and with planar multi-gated blood pool scintigraphy (PMUGA). Likewise, the right ejection fractions of 25 patients were evaluated with first-pass scintigraphy (FP) and with TMUGA. The watershed algorithm was applied to the reconstructed slices in order to group together the voxels whose activity came from one specific cardiac cavity. First, the results of the watershed algorithm were compared with manual drawing around left and right ventricles. Left ejection fractions evaluated by TMUGA with the watershed procedure were not significantly different (p=0. 30) from manual outlines whereas a small but significant difference was found for right ejection fractions (p=0.004). Then right and left ejection fractions evaluated by TMUGA (with the semi-automatic segmentation procedure) were compared with the results obtained by FP or PMUGA. Left ventricular ejection fractions evaluated by TMUGA showed an excellent correlation with those evaluated by PMUGA (r=0. 93; SEE=5.93%; slope=0.99; intercept = 4.17%). The measurements of these ejection fractions were significantly higher with TMUGA than with PMUGA (P<0.01). The interoperator variability for the measurement of left ejection fractions by TMUGA was 4.6%. Right ventricular ejection fractions evaluated by TMUGA showed a good correlation with those evaluated by FP (r = 0.81; SEE = 6.68%; slope = 1.00; intercept = 0.85%) and were not significantly different (P = 0.42). The interoperator variability with TMUGA was 6.7% for the right ventricle. Thus, the watershed algorithm proposed is an efficient segmentation tool for the semi-automatic analysis of right and left ventricular ejection fractions by TMUGA. Further studies are necessary to check whether this procedure can be used to evaluate ventricular volumes and cardiac outflow.

Algorithms↗
PubMed2004

Late-arterial and portal-venous phase imaging of the liver with a multislice CT scanner in patients without circulatory disturbances: automatic bolus tracking or empirical scan delay?

The value of automatic bolus tracking in late-arterial and portal-venous phase imaging of the liver with a multislice CT scanner as compared with fixed time-delay examination in patients without circulatory disturbances is evaluated. For the evaluation of known or suspected liver disease, 98 multiphase contrast-enhanced CT examinations including double late-arterial phase imaging were randomized into either scanning with a scan delay of 30 s from the beginning of contrast material injection or scanning with automatic bolus tracking. Contrast material was injected at 0.07 ml/kg body weight/s over 30 s. Contrast enhancement in each acquisition was measured in the aorta, portal vein, liver, pancreas and hepatocellular carcinomas. The density difference between hepatocellular carcinomas and the hepatic parenchyma was calculated. The mean time to the first-pass acquisition as determined by automatic bolus tracking was 29.6 s. No statistically significant difference was observed between the two groups either in any enhancement in any acquisition or in the lesion-to-liver density difference. The use of automatic bolus tracking in late-arterial and portal-venous phase hepatic CT does not significantly improve the degree of contrast enhancement in the aorta, portal vein, liver and pancreas or lesion-to-liver conspicuity in patients without circulatory disturbances.

Adult↗
PubMed2001

Biphasic spiral CT of the liver: automatic bolus tracking or time delay?

The aim of this study was to evaluate the value of automatic bolus tracking for biphasic spiral CT of the liver in comparison with time delay examinations. Forty patients scheduled for a biphasic spiral CT of the liver randomly were examined either with time delay of 25 s for the arterial phase and 55 s for the portal-venous phase (n = 20), or with an automatic scan start triggered by contrast enhancement in the aorta (n = 20). Examinations were performed with 120 ml of contrast material and a flow rate of 4.0 ml/s. Density measurements of the aorta, of the liver parenchyma, and of the spleen were obtained by means of regions of interest (ROI). The end of the arterial phase was considered when hepatic parenchymal enhancement was greater than 20 HU. In all patients of the group with automatic bolus tracking arterial scanning was completed in the arterial phase of the liver. In 25 % of patients with fixed time delay, however, an enhancement of liver parenchyma during arterial phase greater than 20 HU was observed. During the portal-venous phase there was no significant difference in parenchymal enhancement between both groups. Automatic bolus tracking allows an individualized timing of the arterial phase in biphasic spiral CT of the liver. The timing is more accurate than in time delay scanning.

Adult↗
PubMed2005

Intelligibility of laryngectomees' substitute speech: automatic speech recognition and subjective rating.

Substitute speech after laryngectomy is characterized by restricted aero-acoustic properties in comparison with laryngeal speech and has therefore lower intelligibility. Until now, an objective means to determine and quantify the intelligibility has not existed, although the intelligibility can serve as a global outcome parameter of voice restoration after laryngectomy. An automatic speech recognition system was applied on recordings of a standard text read by 18 German male laryngectomees with tracheoesophageal substitute speech. The system was trained with normal laryngeal speakers and not adapted to severely disturbed voices. Substitute speech was compared to laryngeal speech of a control group. Subjective evaluation of intelligibility was performed by a panel of five experts and compared to automatic speech evaluation. Substitute speech showed lower syllables/s and lower word accuracy than laryngeal speech. Automatic speech recognition for substitute speech yielded word accuracy between 10.0 and 50% (28.7+/-12.1%) with sufficient discrimination. It complied with experts' subjective evaluations of intelligibility. The multi-rater kappa of the experts alone did not differ from the multi-rater kappa of experts and the recognizer. Automatic speech recognition serves as a good means to objectify and quantify global speech outcome of laryngectomees. For clinical use, the speech recognition system will be adapted to disturbed voices and can also be applied in other languages.

Humans↗
PubMed2004

Fuzzy logic automatic control of the Phoenix-7 total artificial heart.

Automatic physiological control of the pneumatic Phoenix-7 total artificial heart (TAH) occupies a pivotal position for clinical application of the device. We developed a fuzzy logic automatic control algorithm for the Phoenix-7. The object of the automatic control system is to regulate the cardiac output at a level desirable for the given preload. The system uses cardiac output-type fuzzy pressure control combined with expert knowledge, most of which is of the form "If condition, then action." As a demonstration of the utility of the control algorithm, the effects of inlet air pressures, aortic pressure, pulmonary artery pressure, and heart rate on the cardiac output were analyzed. In addition, an in vitro experiment was carried out that verified good performance of the control algorithm. This fuzzy logic control algorithm possesses the potential for totally automatic operation, eliminating any need for manual intervention under variable hemodynamic conditions.

Automation↗
PubMed1975

Effect of manganese chloride and Verapamil on automaticity of digitalized Purkinje fibers.

The effects of manganese chloride (MnCl2) and verapamil on automaticity of digitlazied Purkinje fibers were studied using conventional microelectrode techniques. The stduied wer made in isolated, spontaneously beating Purkinje prearations. Quabain alone consistently increased the automatic rate, whereas no such increase was observed when the preparations were superfused with a mixture of ouabain adn MnCl2. MnCl2 was also shown to be effective is suppressing the enhanced automaticity induced by ouabain. Mncl2 alone did not have a significant effect on the spontaneous rate of Purkinje fibers. The effect of verapamil was similar to that of MnCl2 in preventing and suppressing the ouabain-induced increase in automaticity. MnCl2 and verapamil have been shown to inhibt tha slow inward calcium current of cardiac fibers. The results therefore suggest that an inward calcium ion current may play a role in the development of digitalis-induced increase in the stope of phase 4 depolarization in Purkinje fibers.

Animals↗
PubMed1993

Changes in early 'automatic' postural responses associated with the prior-planning and execution of a compensatory step.

There is growing interest in the perturbation-evoked stepping response as an important element in the movement repertoire to maintain upright stance. It is possible that there is an important relationship between the well-documented, early 'automatic' postural responses and subsequent stepping responses. In this study, we characterize changes in early 'automatic' postural responses associated with the prior-planning and execution of a compensatory (i.e. stabilizing) stepping response. Seven subjects were tested on a 'moveable' platform which could translate in the anterior-posterior direction. The subjects' responses were analyzed for two different tasks: (1) 'constrained' (keep feet in place), and (2) perturbation-cued 'reaction time' stepping (step when the platform moves). Only responses to forward platform translations were analyzed in this study. Responses for each of these tasks were evoked using two different perturbation magnitudes. The higher magnitude was sufficiently large to evoke stepping responses in a large proportion of the 'constrained' trials despite instructions not to step. We compared the magnitude of the early evoked postural reactions between trials when subjects had pre-planned a stepping response against trials characterized by either (1) no stepping or (2) unplanned stepping responses. The results revealed that the early 'automatic' responses in tibialis anterior were always present in all subjects and all tasks. However, the evoked 'automatic' responses were approximately 36% smaller (over the first 50 ms) when followed by a pre-planned stepping response ('reaction-time' task). This task-related difference was similar for both perturbation magnitudes i.e. it occurred regardless of whether the 'constrained' tasks involved feet-in-place responses (small perturbations) or stepping responses (large perturbations).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Automatic seizure detection: improvements and evaluation.

Improvements to an existing automatic seizure detection program are described. They are aimed at taking into account a larger temporal context and thus improving the specificity of the detections. Results were evaluated on 293 recordings from 49 patients, totaling 5303 h of 16-channel recording. They showed that 24% of the 244 seizures recorded were missed by the automatic detection; in 41% of the seizures, the patient alarm was not pressed but the computer made detections. The false detection rate was of the order of 1 false detection per hour of recording. Conclusions are: (1) automatic seizure detection must be used in conjunction with a patient alarm button since some seizures, having poorly defined EEG activity, are not detected; (2) the automatic detection allowed capture of many seizures, clinical and subclinical, for which the alarm was not pressed; (3) the low false detection rate indicates that lower detection threshold could be used, yielding better seizure detection.

Adolescent↗
PubMed1996

Clinical application of automatic integrative interpretation of awake background EEG: quantitative interpretation, report making, and detection of artifacts and reduced vigilance level.

Methods for the automatic detection of artifacts and vigilance level of the EEG record were developed for a preprocessing procedure for the automatic integrative interpretation of awake background EEG. All equations for the detection were derived such that they would conform to the procedure that an EEGer adopts for visual EEG inspection. The automatic EEG interpretation system was improved by adding the proposed preprocessing procedure and gave satisfactory interpretation results for the EEG data even contaminated with artifacts or in the drowsy state. The automatic EEG interpretation method proposed here is suggested for clinical use as an assistant tool for EEGers and physicians.

Arousal↗
PubMed1976

Tricyclic antidepressants and cardiac conduction: changes in ventricular automaticity.

Ventricular dysrhythmias result from changes in the automaticity or the conduction properties of the specialized conduction system. Tricyclic antidepressants have been reported to cause ventricular dysrhythmias in humans and experimental animals. Consequently, it seemed to interest to determine whether these substances influence ventricular automaticity. Ventricular rhythm was produced in anesthetized dogs by blocking atrioventricular conduction. Low doses of imipramine, amitriptyline and nortriptyline resulted in small but significant increases in automaticity. Relatively high doses of these agents suppressed automaticity markedly. These changes could play a role in the development of dysrhythmias.

Amitriptyline↗
PubMed1991

The time course of automatic lexical access and aging.

This study addresses the issue of cognitive slowing in the elderly by examining the time course of automatic lexical access. College-aged subjects typically show a brief rise time (300-500 msec) for lexical access. In the present study, we examine whether there are changes in rapid, automatized access routines with age. Elderly and college-aged subjects performed a lexical decision task wherein semantically related words embedded in a continuous list were presented one at a time with a varying (300-1500 msec) inter-word interval. The use of a continuous list, a repeated word, and a very short inter-stimulus interval allowed automatic lexical access to be straightforwardly examined. The elderly subjects showed an onset of automatic lexical access that was similar in time frame to that for college-age subjects. These findings suggest that wherever the locus of age-related slowing may be, it is not in the early, language-specific processing devices that mediate lexical access.

Adult↗