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At least 757 records · Page 42Linked to original sources
PubMed1982

Automatic recognition of epileptic seizures in the EEG.

During prolonged EEG monitoring of epileptic patients, the continuous EEG tracing may be replaced by a selective recording of ictal and interictal epileptic activity. We have described previously methods for the EEG recording of seizures with overt clinical manifestations and for the automatic detection of spikes. This paper describes a method for the automatic detection of seizures in the EEG, independently of the presence of clinical signs; it is based on the decomposition of the EEG into elementary waves and the detection of paroxysmal bursts of rhythmic activity having a frequency between 3 and 20 c/sec. Simple procedures are used to measure the amplitude of waves relative to the background, their duration and rhythmicity. The evaluation of the method on 24 surface recordings (average duration 12.4 h) and 44 recordings from intracerebral electrodes (average duration 18.7 h) indicated that it was capable of recognizing numerous types of seizures. False detections due to non-epileptiform rhythmic EEG bursts and to artefacts were quite frequent but were not a serious problem because they did not unduly lengthen the EEG tracing and they could be easily identified by the electroencephalographer. The program can perform on-line and simultaneously the automatic recognition of spikes and of seizures in 16 channels.

Brain↗
PubMed1984

Analysis of EEG changes with carotid clamping by selective analog filtering, matched inverse digital filtering and automatic adaptive segmentation: a comparative study.

A comparative evaluation was made of 3 methods for possible use in a system for automatic evaluation and signaling of significant EEG changes associated with carotid clamping. The methods were: (1) selective analog filtering in two frequency bands ("fast'--4-20 c/sec; and "slow'--0.8-1.0 c/sec); (2) inverse digital filtering, a computer-based method in which a filter is formed from a pre-clamping EEG baseline such that only frequency components different from the baseline components appear in the filter output; and (3) automatic adaptive segmentation, a computer-based method of detecting and signaling EEG changes by comparison of the autocorrelogram of a pre-clamping reference sample with that from an equal-duration sample "seen' through a progressively moving window in the post-clamping period. For the analyses, portions of ink-recorded monitoring EEGs previously interpreted as showing changes consequent to carotid clamping were transferred to a cassette tape recorder system by means of a multichannel photo-optical scanning system. Of the 3 methods, automatic adaptive segmentation was clearly the best. For selective analog filtering, the thresholds for a significant change were difficult to set. Inverse digital filtering was unsatisfactory because of its insensitivity to changes in the amplitude frequency components already present, although new frequency components could be detected. An incidental finding was that a slow-speed write-out of the analog filter outputs provided a good visual indication of EEG changes.

Brain↗
PubMed1986

Automatic analysis of sleep records with static charge sensitive bed.

An automatic analysis of movements detected by the static charge sensitive bed (SCSB) was developed for the study of sleep and breathing disturbances (apnoeas) during sleep. Three signals on separate channels are analysed: one relating to body movements, one to respiratory movements and one to movements of the heart (ballistocardiogram). The analysis can be made on-line or from tape recordings. With a portable microcomputer the records and analyses can be carried out at home or on the ward without any professional personnel. The system can be preset to start and to end recording automatically. The subject just has to lie down. The automatic analysis of body movements on the basis of their amplitude and duration yields criteria for scoring of sleep into 'wakefulness,' 'quiet sleep' and 'active sleep.' A simple hypnogram and the statistics on the durations and proportions of these stages are printed. Simultaneous SCSB and polygraphic records were made on healthy subjects. Comparison of the two types of sleep scoring showed that the results agreed during 81% of the time. The amplitudes of the movements detected on the 3 channels are integrated in epochs and the results of this analysis are represented in a compressed graphic form which allows easy visualization of the overnight records. The pattern of 'respiratory movements' reveals whether the breathing has been regular, irregular or periodic.

Adult↗
PubMed1991

Event-related potentials and eyeblink responses in automatic and controlled processing: effects of age.

Seventeen young (mean age = 20.2 years old) and 16 elderly (mean age = 72.6 years old) women were tested with event-related potential (ERP) paradigms designed to elicit responses in reaction time tasks and to a startling noise burst. EEG was analyzed from 17 standard 10-20 electrode sites. Reaction time and performance data suggested that the elderly did not perform worse than the young. Nevertheless, the physiological responses of the elderly differed significantly from those of the young. While the task-dependent P3s at Pz were smaller in the elderly than in the young, the automatic P3 was smaller yet. The distribution of both types of P3 across the scalp was more uniform in the elderly than in the young. Single-trial analyses revealed that the P3 amplitude differences at Pz were not due to latency dispersal of single trials. Single-trial startle eye blink responses to intense noise bursts during the automatic paradigm were considerably less frequent in the elderly, although their individual startle blinks were actually larger. The data demonstrate that the electrophysiological responses of the elderly are different from the young both in tasks eliciting automatic responses and in tasks requiring controlled processing.

Adult↗
PubMedDate not supplied

Suppression of ventricular automaticity by antidysrhythmic agents.

In view of the potentially important role of automaticity in the genesis of ventricular dysrhythmias, the effects of four widely used antidysrhythmic agents on ventricular automaticity were examined in anesthetized dogs at doses previously shown to antagonize experiments induced rhythm disturbances. Quinidine, and particularly procainamide, lidocaine and propranolol slowed ventricular rate in A-V blocked dogs. Quinidine and procainamide but particularly the last two agents also markedly prolonged overdrive suppression. Thus, all four substances depressed automaticity. However, propranolol was effective at doses substantially lower than those required to antagonize several experimental dysrhythmias.

Animals↗
PubMed1976

Automatic registration of behaviour related to dopamine and noradrenaline transmission.

In a search for behavioural tests where certain behaviours related to dopamine and noradrenaline transmission can be recorded automatically we have developed and tested an automatic version of the hole board. The test measures two behaviour variables: the open field variable defined as the number of interruptions of photocell beams symmetrically covering an open field area and the 'hole' variable, defined as the number of head-dips into holes recorded by photocell beams positioned underneath the floor of the cage. The method was evaluated by observations of the rats concomitant with the automatic registrations. The animals were tested on dopamine agonistic drugs, which were found to decrease the 'hole' counts and cause an increase in the open field counts as compared to saline injected controls. d-Amphetamine which is known to increase the release of dopamine as well as of noradrenaline caused an increase in both the open field counts and the 'hole' counts. The increase in 'hole' counts caused by d-amphetamine was reduced when the animals were pretreated with a dopamine-beta-hydroxylase inhibitor (FLA 63) or a noradrenaline receptor blocker (phenoxybenzamine). These results suggests that the increase in the 'hole' variable was related to an increased noradrenaline transmission while the increase in the open field variable was related to an increased dopamine transmission. The lowest dose of apomorphine caused a behavioural inhibition which may be explained by a preferential stimulation of dopamine autoreceptors.

Amphetamine↗
PubMed1982

Biphasic effects of acetylstrophanthidin on automaticity in guinea pig ventricular muscle.

The effects of acetylstrophanthidin (AS) on depolarization-induced automaticity and contractility of guinea pig papillary muscle were studied in a single sucrose gap chamber with microelectrode and current-clamp techniques. The concentration used, 1.4-1.8 microM, never induced automaticity in preparations at their normal resting potential. Twenty min after superfusion with AS, action potential duration (APD) was prolonged and the force of contraction increased. These were associated with an increase in slope of phase 4 depolarization and an increase in the membrane resistance (Rm) of muscles depolarized with small constant current pulses. With longer (50-80 min) periods of AS superfusion, APD became shorter, Rm decreased to less than predrug values, and in depolarized preparations, the slope of phase 4 decreased. Contractility remained unchanged throughout this second phase. All of these effects were fully reversible upon 60 min of superfusion with AS-free Tyrode solution. We suggest that the biphasic effects of AS on the automaticity of depolarized ventricular muscle cells are caused by an initial decrease followed by a later increase in transmembrane potassium conductance.

Animals↗
PubMed1988

Theophylline antagonizes the effect of diazepam on ventricular automaticity.

The effect of diazepam on ventricular automaticity induced by a local injury was investigated in the isolated right ventricle of the rat in the presence of the diazepam central antagonist, RO 15-1788, and of the adenosine antagonist, theophylline. Theophylline but not RO 15-1788 antagonized the inhibitory effect induced by diazepam on ventricular automaticity. The inhibitory effect of adenosine but not that of 2-chloroadenosine was potentiated in the presence of diazepam. The results suggest that the inhibitory effect of diazepam on ventricular automaticity results from the inhibition of adenosine uptake.

Adenosine↗
PubMed1982

A personal reference retrieval system for medium sized computers allowing automatic data entry from ONLINE databases.

A series of programs has been developed for the storage and retrieval of bibliographic references, which allow automatic cross-referencing of the stored entries. Reference retrieval becomes successively faster as more searches are performed and references are automatically sub-grouped under indexed terms allow complete sub-sets to be scanned independently. The indexing allows complete sub-collections of references to be printed, e.g. for a review, with no further searching requirements. This style of retrieval is conceptually similar to card systems in use by many scientists and should enable a rapid familiarization with the retrieval system. The editing features of the programs provide for the direct collection of references from large ONLINE databases (e.g. MEDLINE) and the automatic entering of the references into the personal data collection. The programs provide reliable storage of references for individual scientists, so that their collections from library databases, or from manual input may be updated and searched quickly.

Abstracting and Indexing↗
PubMed1989

Automatic speech recognition--can it improve the man-machine interface in medical expert systems?

Computer-aided medical diagnosis has existed for two decades, but has not yet attained widespread acceptance among physicians. It is proposed that automatic speech recognition may be a significant factor in the eventual acceptance of the technology by the medical profession. The current state-of-the-art of automatic speech recognition is briefly surveyed, and problems with the technology are discussed. A potential natural language interface with DIAG, an expert system for aiding in dermatologic diagnosis, is described. A system that has been developed for accepting input of body parts in freestyle format is presented as a prototype for a natural language interface with an automatic speech recognition device.

Diagnosis, Computer-Assisted↗
PubMed1995

Adenosine and ventricular automaticity.

Adenosine is considered a cardiodepressant agent due to its negative chronotropic and inotropic effects. However, the effect of adenosine on ventricular automaticity is less well established since both an increase and a decrease in ventricular automaticity have been reported. The experimental and clinical evidence dealing with the effects of adenosine on ventricular automaticity as well as the possible mechanisms involved, is presented in this review.

Adenosine↗
PubMed1979

The variation of the mean spinability of human cervical mucus throughout the various stages of reproductive life. Automatic measurement and statistical study.

The evolution of the mean spinability value of human cervical mucus was studied by means of an automatic device throughout the menstrual cycle and pregnancy and during and after the onset of menopause. The automatic measurement brings to light the major drawbacks presented by manual methods: values previously obtained should be considered as underestimated. The mean spinability value recorded from cyclic mucus exhibits a very significant increase at mid-cycle. Graphical analysis demonstrates that only small differences in the mean spinability value occur as pregnancy proceeds. A progressive and regular decrease in the mean spinability value can be recorded from the very beginning of the menopause. However, the spinability values observed in premenopausal mucus are noticeably higher than those recorded after the onset of the menopause. The numeric data furnished by the automatic measurement are discussed in terms of statistics.

Cervix Mucus↗
PubMed1996

Lateralization of brain mechanisms underlying automatic and controlled forms of spatial orienting of attention.

Unilateral Spatial Neglect (USN) can be considered as a defect in spatial orienting of attention toward the half space contralateral to the damaged hemisphere. Since the classical work of Brain, W.R. Brain 64:224-272 (1941), several authors have emphasized that this defect is definitely more frequent and severe in patients with right brain damage, but the reason for this hemispheric asymmetry has remained controversial. Several investigations conducted with different experimental paradigms in different laboratories have shown that only automatic orienting of attention toward stimuli arising in the half space contralateral to the damaged hemisphere is disrupted in USN, whereas controlled, volitional orienting can be more or less completely spared. The hypothesis that at the level of the right hemisphere, spatial orienting of attention may be mainly prompted by automatic mechanisms may, therefore, be advanced. By contrast, the left hemisphere might play a leading role in mechanisms underlying volitional orienting of attention. According to this model, recovery from USN could be due to substitution of the lost automatic orienting mechanisms with the spread volitional orienting mechanisms subserved by the intact left hemisphere.

Attention↗
PubMed1983

An automatic neuron reconstruction system.

Most contemporary neuron tracing systems are semi-automatic; that is, an operator follows neuron branches in a microscope or on a data tablet and instructs a computer when to record a spatial sample. A list of such samples is then used to generate a display of the neuron and to summarize statistically its structure. The tracing is tedious, and the operator must make subjective decisions about point types, thus biasing the results. A fully automatic system in which the computer views the image through a television digitizing system has been constructed. The computer follows the fibers and recognizes branchpoints and fiber endings. The coordinates, types of points, and fiber diameters are recorded in computer memory. An operator is required only to start the tracing of a fiber and to help the computer when it becomes "confused". The results are mixed. The computer can follow fibers quite successfully and can determine branches and endings with some success, but the procedure is an order of magnitude more slow than that of a skilled operator using a well-designed semi-automatic system.

Computers↗
PubMed1993

An automatized computer-method utilizing Procomm Plus and DataEase (4.2) PC and SAS (6.06) mainframe software for isolated, perfused guinea-pig heart studies.

A powerful, time sharing and automatized method of a comprehensive data analysis for isolated, perfused guinea-pig heart studies is described. Data are collected using DataEase PC software (version 4.2) into forms with data fields specified for vital parameters consistently recorded in isolated, perfused heart studies (HR, CBF, PEAKPRESSURE, DPDT, MVO2). After running, DataEase reports the data and information is uploaded to an IBM 3081D mainframe computer on each day of heart experiment and data collection. The uploading process, the data archival and the statistical analyses are automatized by Procomm Plus commands written in Aspect Source Program (.ASP) Files for logging, data transforming and file management procedures. The ASPCOMP.EXE compiler compiles these .ASP files into Aspect Script eXecutable (.ASX) programs, which run on the PC in our laboratory and activate WYLBUR (IBM 3081D Batch-job service and Command file processor) edited files in the mainframe's electronic devices then upload, backup and save data into these files. SAS EXE files containing program instructions for the data analyzing system are then forced by Procomm Plus to operate over the data just uploaded. SAS reads the DATA files by its INFILE facility and performs comprehensive statistical analyses and produces hard output including graphics and JOB reports of dose-response- and logaritmic scale curves for delivery to team members. This computerized and automatized method developed for isolated, perfused guinea-pig heart studies is capable of performing multiple file transfer, sophisticated statistical analyses and graphic procedures after one keystroke on the PC (Alt-F5 in Procomm Plus section) and also facilitates a consistent and convenient method for planning, controlling and standardizing experiments. The method is based on an interactive computer conversation between the PC in the laboratory and the remote's WYLBUR editor. No human presence is needed; however, in case of failure, Procomm Plus gives one of the team members supervising the system a phone call in order to get human help.

Animals↗
PubMed1995

IT-based evaluation and automatic improvement of the quality of intraoral radiographs.

The quality of intraoral radiographs made in dental practices is too often not adequate for diagnostic purposes. This necessitates standardized measures for the quality of intraoral radiographs and controlled techniques for automatic image improvement. For the evaluation of the quality of digitized intraoral radiographs the authors have defined two parameters which enable the measurement of radiographic image quality with regard to contrast and gray value distribution. A two-dimensional feature space based on these parameters is used for separation of images with 'good diagnostic quality' from images with 'insufficient diagnostic quality'. Specific image improvement techniques based on piecewise linear gray scale transformation allow the automatic improvement of over- and under-exposed radiographs as well as the automatic improvement of suspected pathological regions of interest.

Humans↗
PubMed1996

Automatic image analysis of antibody assays to measles virus.

A system for the automatic analysis of 24-well plates used in antibody assays to measles virus has been designed and developed based on digitising the information on the plate through a CCD camera, displaying the image and then analysing it using image processing methods. The system is being used in the analysis of sera from individuals vaccinated against measles and has been compared with the previous method where the plates were assessed by eye. The results from both methods are very similar although the manual method consisted of counting numbers of plaques (clear areas in the cells of the plate) and the automatic method measured plaque area. The automatic method is much faster than the original method and prevents operator fatigue. It does not deal, at present, with anomalies such as partially filled wells but could be developed to do so by incorporating intelligence into the system.

Antibodies, Viral↗
PubMed1995

A rudimentary system for automatic discrimination among basic skin lesions on the basis of color analysis of video images.

BACKGROUND: Detection of differences in color is necessary for an automatic diagnostic system for skin lesions. OBJECTIVE: The purpose of this study was to examine whether color analysis of an image obtained with a videomicroscope can be used as a key to distinguish basic skin lesions. METHODS: We carried out quantitative color analyses of nine kinds of natural or artificial skin lesions. After images of the lesion and adjacent normal skin were obtained, the difference in the mean quasiabsorbance (logarithm of the inverse reflectance) values between the two were examined in each color band of red, green, and blue by an image analytic method. RESULTS: We could determine a set of thresholds of quasiabsorbance values to distinguish between basic lesion colors. On the basis of these results we developed a rudimentary system that automatically offers possible diagnoses of a test site. CONCLUSION: The algorithm that we developed may be of value in an initial screening of skin lesions in an automatic diagnosis system.

Absorption↗