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 19 recordsLinked to original sources
PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗
PubMed1991

Anesthetics and automaticity in latent pacemaker fibers: I. Effects of halothane, enflurane, and isoflurane on automaticity and recovery of automaticity from overdrive suppression in Purkinje fibers derived from canine hearts.

Knowledge of arrhythmic or antiarrhythmic actions of anesthetics on automaticity of latent pacemaker fibers has relevance to the intraoperative management of patients with bradyarrhythmia due to sinus node dysfunction or heart block. The authors determined the effects of halothane, enflurane, and isoflurane on automaticity and recovery of automaticity from overdrive suppression in canine Purkinje fibers derived from normal hearts. Purkinje fibers were superfused with a modified Krebs' solution (37 degrees C) containing epinephrine (2 or 15 microM) and equilibrated with a 97% O2-3% CO2 gas mixture (control). Transmembrane action potentials (AP) were recorded using standard microelectrode techniques. Purkinje fibers were then exposed to anesthetics at vaporizer settings of 0.75 or 1.5% (halothane), 1.75 or 3.5% (enflurane), and 1 or 2% (isoflurane), which were equivalent to measured superfusate concentrations of 0.22 or 0.47 mM (halothane), 0.44 or 0.94 mM (enflurane), and 0.28 or 0.53 mM (isoflurane). Compared to control, there was no significant effect of either concentration of the anesthetics on upstroke (phase 0) depolarization, AP amplitude or duration (50% repolarization), or maximum diastolic potential. All three anesthetics increased spontaneous rate. The increase in rate with all three anesthetics was due to enhanced diastolic depolarization (rate dV/dt, phase-4 depolarization). Recovery times from overdrive suppression were determined after 30 or 60 s of pacing at drive cycle lengths of 800, 500, and 400 ms and only at higher anesthetic concentrations. Recovery of automaticity was shortened by halothane only in slowly paced fibers exposed to the lower concentration of epinephrine. Under all other conditions recovery times were not affected by halothane.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1999

Uni- and bipolar pacing threshold measurements with capturecontrol, a new automatic pacemaker function for capture verification. Comparison of the automatic and the manual pacing threshold measurement.

It is mandatory in pacemaker patients to determine the pacing threshold at each follow-up visit. To facilitate the pacing threshold measurements, complete automatic pacemaker tests are being developed. A new pacemaker algorithm for automatic capture verification (Capturecontrol) detects the presence of the evoked response signal 70-100 ms after the pacing pulse. The aim of this study was to determine the uni- and bipolar pacing thresholds using this automatic pacemaker function and compare them with the manually determined threshold. The study included 14 patients with the DDD pacemaker Logos (Biotronik) connected to the high-ohmic ventricular pacing lead Synox SX 60-BP (Biotronik). At predischarge and 8, 14, 20 and 26 weeks after implantation the uni- and bipolar pacing thresholds were assessed manually and with the automatic pacemaker function at 0.4 ms duration. Mean pacing thresholds determined with the automatic pacemaker function were not different from the manually measured values. This applied to uni- and bipolar pacing. Seventy percent of all unipolar and 67% of all bipolar measurements had no deviation. A deviation of 0.1 V between manual and automatic threshold measurement was observed in 25% (unipolar) and 28% (bipolar), respectively. A 0.2-volt difference occurred in 3% in the unipolar measurements. Deviations >/=0.3 V were found in 2% of all unipolar and in 5% of all bipolar measurements. In conclusion, automatic pacing threshold measurements using the Capturecontrol algorithm were similar compared to the manually determined thresholds. The excellent agreement between the two methods was observed for bipolar as well as unipolar pacing and on condition that all patients had a high-ohmic ventricular pacing lead. Therefore, fewer requirements are necessary for Capturecontrol than for presently available systems. Such pacemaker functions can help to speed up the measurements during follow-up visits.

Aged↗
PubMed1992

The ecology of automaticity: toward establishing the conditions needed to produce automatic processing effects.

In the past 15 years, the single term automatic has been applied to a diversity of laboratory phenomena that differ as to the preconditions necessary for their occurrence. Several major strains of automaticity are distinguished, based on the experimental conditions under which they are obtained: preconscious automatic processes, requiring only the proximal stimulus event; postconscious automatic processes, similar to preconscious effects but needing a recent activation or "priming" event for their operation; and goal-dependent automatic processes, which occur only when a specific, intentional processing goal is in place. It is argued that to more accurately specify the conditions under which an automatic effect will occur in the natural environment, greater attention needs to be given to aspects of the experimental paradigm (e.g., subjects' task goal, questionnaire administrations, previous tasks) that might be necessary to produce the effect.

Association Learning↗
PubMed2001

On the malleability of automatic attitudes: combating automatic prejudice with images of admired and disliked individuals.

Two experiments examined whether exposure to pictures of admired and disliked exemplars can reduce automatic preference for White over Black Americans and younger over older people. In Experiment 1, participants were exposed to either admired Black and disliked White individuals, disliked Black and admired White individuals, or nonracial exemplars. Immediately after exemplar exposure and 24 hr later, they completed an Implicit Association Test that assessed automatic racial attitudes and 2 explicit attitude measures. Results revealed that exposure to admired Black and disliked White exemplars significantly weakened automatic pro-White attitudes for 24 hr beyond the treatment but did not affect explicit racial attitudes. Experiment 2 provided a replication using automatic age-related attitudes. Together, these studies provide a strategy that attempts to change the social context and, through it, to reduce automatic prejudice and preference.

Adult↗
PubMed1992

Automatic EEG interpretation: a new computer-assisted system for the automatic integrative interpretation of awake background EEG.

A new computer-assisted system for automatic interpretation of the awake electroencephalogram (EEG) was developed. First, all the items necessary for EEG interpretation were determined in accordance with the procedure that a qualified electroencephalographer (EEGer) goes through for the visual inspection of the background EEG activity, and then each item was defined quantitatively. For the automatic interpretation, specific EEG parameters were determined for each item so that they could fit the graded judgement of the item by the qualified EEGer as closely as possible. These specific EEG parameters were actually calculated from periodograms obtained from the time series of EEG records of 14 patients with various neurological diseases. The automatic EEG interpretation system thus established was applied to the EEG data of these 14 subjects and to 3 additional EEGs, and the results were compared with those obtained through the visual interpretation by the EEGer. This automatic EEG interpretation was found to be in good agreement with the visual interpretation by the EEGer in most EEG records. In contrast with the previous automatic analyses of EEG which were focussed on certain aspects of EEG such as the dominant rhythm, the present system is unique in its capability of providing an integrative interpretation of the spontaneous awake EEG by taking into account all its features except for paroxysmal abnormalities.

Adult↗
PubMed2001

Automaticity and attention: investigating automatic processing in texture segmentation with event-related brain potentials.

The present article deals with the question of automaticity and/or plasticity of processes in early vision. The detection of irregularities in an otherwise homogeneous surrounding, as studied in texture segmentation tasks, is considered an example of an automatic process in the processing of visual information. Participants in texture segmentation experiments are usually instructed to respond to the texture stimuli, i.e. attention is completely allocated towards them. Automaticity, however, would imply that processing takes also place when no attention is allocated to the texture stimuli and participants, e.g. perform another primary task. We investigated the automaticity of texture segmentation by recording Event-related potentials which allow to investigate processing also when no overt response is given. Three experiments investigated the role of attention in texture segmentation by varying task relevance of the texture stimuli. Participants had to either discriminate homogeneous or inhomogeneous textures or had to perform a different primary task of varying complexity. Two components were found to be sensitive to texture segmentation, a posterior N2 and a positivity within the P3 time interval. Both components were also observed when texture segmentation was task-irrelevant. However, while the posterior N2 was not affected by the complexity of the primary task and thus showed some degree of automaticity, the P3 was found to be dependent on the attentional resources left over by the primary task.

Adult↗
PubMed1998

Ictal oroalimentary automatisms with preserved consciousness: implications for the pathophysiology of automatisms and relevance to the international classification of seizures.

A patient showing seizures presenting ictal automatisms with preserved consciousness is reported. A 30-year-old, right-handed man with normal development and without family history of epilepsy was referred for surgical treatment of epilepsy. At 15 he began to have seizures, starting with an epigastric aura, occasionally developing automatisms (lip-smacking, chewing), sometimes followed by tonic-clonic convulsions. At the time of referral, he averaged six convulsive seizures per year and one nonconvulsive per week. His sleep EEG showed sharpened slow activity over the right anterior quadrant magnetic resonance imaging (MRI) showed a benign lesion in the mesial aspect of the right occipital lobe. Simultaneous video monitoring and intracranial EEG with subdural strips recording from the right temporal and occipital lobes was undertaken. During one seizure, he had pronounced oroalimentary automatisms while holding a conversation with a technician, answering her questions, and explaining details of his seizures. Memory of this event was preserved. At seizure onset, spike activity was seen at the mesial occipital strips. At midseizure, high-voltage sharpened delta was seen throughout the right hemisphere. Left-sided scalp electrodes remained relatively uninvolved. The lesion, a dysembryoplastic neuroepithelial tumour was removed. Surgery was followed by abolition of seizures described. Because it is agreed that complex partial seizures require impaired consciousness, a history of automatisms with retained consciousness usually suggests nonepileptic attacks. This case suggests that automatisms in epileptic seizures can take place with minimal loss of consciousness, particularly if there is widespread but unilateral involvement. The need for a revision of the International Classification is suggested.

Consciousness↗
PubMed1998

Automatic calculation of total lung capacity from automatically traced lung boundaries in postero-anterior and lateral digital chest radiographs.

Total lung capacity (TLC) is a very important parameter in the study of pulmonary function. In the pulmonary function laboratory, it is normally obtained using plethysmography or helium dilution techniques. Several authors have developed methods of calculating the TLC using postero-anterior (PA) and lateral chest radiographs. These methods have not been often used in clinical practice. In the present work, we have developed and automated computer-based method for the calculation of TLC, by determining the pulmonary contours from digital PA and lateral radiographs of the thorax. The automatic tracing of the pulmonary borders is carried out using: (1) a group of reference lines is determined in each radiograph; (2) a family of rectangular regions of interest (ROIs) defined, which include the pulmonary borders, and in each of them the pulmonary border is identified using edge enhancement and thresholding techniques; (3) removing outlaying points from the preliminary boundary set; and (4) the pulmonary border is corrected and completed by means of interpolation, extrapolation, and arc fitting. The TLC is calculated using a computerized form of the radiographic ellipses method of Barnhard. The pulmonary borders were automatically traced in a total of 65 normal radiographs (65 PA and 65 lateral views of the same patients). Three radiologists carried out a subjective evaluation of the automatic tracing of the pulmonary borders, with a finding of no error or only one minor error in 67.7% of the PA evaluations, and in 75.9% of the laterals. Comparing the automatically traced borders with borders traced manually by an expert radiologists, we obtained a precision of 0.990 +/- 0.001 for the PA view, and 0.985 +/- 0.002 for the lateral. The values of TLC obtained by the automatic calculation described here showed a high correlation (r = 0.98) with those obtained by applying the manual Barnhard method.

Adolescent↗
PubMed1985

Automatic measurement of blood pressure: evaluation of the Copal UA-231 automatic sphygmomanometer.

The suitability of an automatic sphygmomanometer for epidemiological work was evaluated in two studies. In the first, blood pressure measurements were made alternately on the automatic machine and on a Hawksley random zero instrument on 14 volunteers on each of four consecutive days by a single medical observer. No significant difference was found between the mean diastolic pressure obtained by each instrument but the mean systolic pressure was 5 mm higher on average on the automatic machine. In the second study, the effect of cuff position for the automatic instrument was examined. Differences between recommended and errant cuff positions of up to 4.5 mmHg were recorded but these did not reach statistical significance. These studies indicate that if used carefully this automatic instrument is suitable for survey and experimental use.

Adult↗
PubMed2002

Comparison of semi-automatic and automatic data acquisition methods for studying three-dimensional distributions of large neuronal populations and axonal plexuses.

Neuroanatomy is in need of high throughput methods for reliably recording the distribution of tissue elements across large brain regions. We compared two methods for recording the spatial distribution of identified neuronal elements such as tracer labelled cell bodies or axonal plexuses. The methods compared were computerized image-combining microscopy (semi-automatic method), which is a user controlled method providing feedback during digitization, and digital camera technology with image analysis software (automatic method). Both methods were applied to biotinylated dextran amine labelled axonal plexuses and FluoroRuby labelled neuronal cell bodies, in the pontine nuclei of the rat. Coordinates were assigned to the labelled elements using both methods. The ensuing distribution patterns were compared, section by section, and in three-dimensional reconstruction. The experienced investigator, using the semi-automatic method, could detect individual axons, fragments of axons, weakly labelled elements, and overlapping cell bodies, better than the automatic system. Nevertheless, both methods detected the overall distribution of the labelled axons and cells investigated. Automatic methods provide opportunities for efficient large-scale data acquisition of labelled neuronal elements.

Animals↗
PubMed1982

The Peritest, a new automatic and semi-automatic perimeter.

The Peritest is a new automatic and semi-automatic (manual) perimeter for detection and limited assessment of visual field defects. It uses either multiple or single stimulus static perimetry. The lightsources are LED's. A total of 206 positions can be examined including the center; 151 positions inside 25 degrees-eccentricity. The programmes use a threshold-related gradient adapted suprathreshold (0.6) strategy. The results are printed on a special chart using non-interpolated grey scales for indicating local reduction of sensitivity. General and local reduction of sensitivity are separated. The progress of the examination can be followed on a LED-monitor. The reliability of the patient is measured. 70% of small early glaucomatous defects (that are only found by high resolution meridional static perimetry) were detected. Such defects are not usually detected by routine kinetic perimetry. More peripheral defects were detected (greater than 25 degrees) than by kinetic perimetry. Due to the relatively high number of stimuli the typical configuration of defects was satisfactorily demonstrated for defects of moderate size and larger. The duration of the examination varies from less than 4 min. for a semi-automatic examination of normal eyes to 10-20 min. for automatic examination of eyes with defects of moderate size (average 15 minutes for 206 positions).

Glaucoma↗
PubMed1992

Hypnotic susceptibility and verbal automaticity: automatic and strategic processing differences in the Stroop color-naming task.

The original hypothesis of Dixon, Brunet, and Laurence (1990) that highly hypnotizable (HH) subjects process words more automatically than do low hypnotizable (LH) subjects was retested in a paradigm that separated strategic from automatic processes in the Stroop color-naming task. The words red and blue preceded a color patch that was red or blue. Subjects were told that the word predicted the opposite color 75% of the time. Automatic and strategic processes were assessed by varying the interstimulus interval (ISI) between the word and the color patch. Both HH and LH subjects showed significant strategic effects (faster incongruent-trial, color-naming reaction times than congruent-trial reaction times at ISIs over 400 ms), but only HH subjects showed significant automaticity (significantly faster congruent-trial reaction times than incongruent-trial reaction times at 16.7 ms, the lowest ISI).

Adult↗
PubMed1991

Anesthetics and automaticity in latent pacemaker fibers. III. Effects of halothane and ouabain on automaticity of the SA node and subsidiary atrial pacemakers in the canine heart.

Atrial tachyarrhythmias are a common manifestation of digitalis toxicity. Such arrhythmias could be due to enhanced automaticity of subsidiary atrial pacemakers (SAP) compared to the sinoatrial (SA) node. Halothane is known to oppose digitalis-induced ventricular arrhythmias. Its effect on digitalis-caused atrial arrhythmias is unknown. Therefore, we tested two hypotheses, as follows. First, increasing ouabain concentrations would enhance automaticity of SAP compared to the SA node and that such enhanced automaticity could explain digitalis-caused atrial tachyarrhythmias. Second, halothane would oppose such enhanced automaticity of SAP, thereby opposing digitalis-caused atrial tachyarrhythmias. A canine right atrial preparation was perfused via the SA node artery with Krebs' solution (36.0 +/- 0.5 degrees C) equilibrated with 97% oxygen-3% carbon dioxide. Four bipolar extracellular electrodes recorded the site of earliest activation (SEA), which in this preparation could be the SA node or increasingly remote sites of SAP approximately 1, 2, and 3 cm distal to the SA node along the sulcus terminalis. Pacemaker shifts to SAP during exposure to drugs were scored for magnitude of shift as 1, 2, or 3 depending on which SAP site was the SEA. Magnitude scores were summed for each test condition and normalized by dividing the total number of preparations tested. Preparations (n = 48) were exposed to 1 or 2% halothane (perfusate concentrations of 0.51 +/- 0.01 or 0.79 +/- 0.03 mM, respectively) and/or to low- or mid-therapeutic (2.5 or 5 x 10(-8) M) or borderline toxic ouabain (1 x 10(-7) M). Normalized magnitude scores were not significantly different from zero (control value) with any halothane or ouabain concentration alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Automatic speech recognition to aid the hearing impaired: prospects for the automatic generation of cued speech.

Although great strides have been made in the development of automatic speech recognition (ASR) systems, the communication performance achievable with the output of current real-time speech recognition systems would be extremely poor relative to normal speech reception. An alternate application of ASR technology to aid the hearing impaired would derive cues from the acoustical speech signal that could be used to supplement speechreading. We report a study of highly trained receivers of Manual Cued Speech that indicates that nearly perfect reception of everyday connected speech materials can be achieved at near normal speaking rates. To understand the accuracy that might be achieved with automatically generated cues, we measured how well trained spectrogram readers and an automatic speech recognizer could assign cues for various cue systems. We then applied a recently developed model of audiovisual integration to these recognizer measurements and data on human recognition of consonant and vowel segments via speechreading to evaluate the benefit to speechreading provided by such cues. Our analysis suggests that with cues derived from current recognizers, consonant and vowel segments can be received with accuracies in excess of 80%. This level of performance is roughly equivalent to the segment reception accuracy required to account for observed levels of Manual Cued Speech reception. Current recognizers provide maximal benefit by generating only a relatively small number (three to five) of cue groups, and may not provide substantially greater aid to speechreading than simpler aids that do not incorporate discrete phonetic recognition. To provide guidance for the development of improved automatic cueing systems, we describe techniques for determining optimum cue groups for a given recognizer and speechreader, and estimate the cueing performance that might be achieved if the performance of current recognizers were improved.

Adolescent↗
PubMed1995

Image analysis of argyrophil nucleolar organizer regions (AgNORs) in oestrogen-induced rat anterior pituitary hyperplasia: comparison of automatized (LUCIA M) and non-automatized evaluation.

Argyrophil nucleolar organizer regions (AgNORs) were morphometrically evaluated in rat anterior pituitaries of control and oestrogenized rats using an automatized (LUCIA M--Laboratory Universal Computer Image Analysis Micro) and a non-automatized approaches to investigate not only the sensitivity and effectiveness of the automatized procedure but also the morphology of AgNORs in oestrogen-induced rat anterior pituitary hyperplasia. In the experimental oestrogen-induced rat anterior pituitary hyperplasia, the image analysis system LUCIA M was compared to a non-automatized morphometric procedure and proved to be very efficient and yielded analogical results. The AgNOR morphology in the oestrogenized pituitaries was characterized by an increase of the total AgNOR area and clustering of AgNORs in the large nucleoli.

Animals↗
PubMed1995

Automatic access of lexical information in Broca's aphasics: against the automaticity hypothesis.

A number of recent articles have claimed that the language comprehension impairments of so-called agrammatic patients can be characterized as being due to problems with the automatic access of semantic and/or syntactic information from the lexicon. We describe three experiments, all using tasks which probe the immediate and automatic access of lexical information and compare the performance of agrammatic patients with that of an anomic and a fluent patient. We find no evidence in support of the automaticity hypothesis as an explanatory account of the language deficits of agrammatic aphasics. Further, we argue that current research does not lend itself to a single-explanation account of agrammatic comprehension problems, and that in-depth analyses of individual patients are more likely to be fruitful in terms of understanding the nature of comprehension deficits.

Aged↗