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PubMed1987

Effects of propafenone on sinus nodal and ventricular automaticity: in vitro and in vivo correlation.

The electrophysiologic effects of the new antiarrhythmic drug, propafenone, were evaluated in anesthetized closed-chest dogs and on isolated cardiac tissues with the microelectrode technique. Propafenone (2 to 4 mg/kg intravenously) had no effect on sinus rate or on sinus nodal recovery time, but caused a dose-dependent significant decrease in the rate of idioventricular rhythm and increased the duration of ventricular overdrive suppression in dogs (n = 8) with complete atrioventricular block. On isolated canine Purkinje fibers (n = 8) manifesting automaticity with resting membrane potential less negative than -70 mV, propafenone reduced the slope of phase 4 depolarization and reduced the rate of automatic impulse initiation in a concentration-dependent manner (10(-6) M-4.10(-5) M). At these concentrations, propafenone had no effect on rabbit sinus nodal automaticity (n = 8) or on sinoatrial conduction. However, significant depression of sinus nodal automaticity occurred with propafenone concentrations above 5.10(-6) M in the presence of cholinergic or complete autonomic blockade with atropine (10(-6) M) and propranolol (5.10(-5) M). Propafenone caused a concentration-dependent decrease in the disparity of Purkinje fiber-ventricular muscle action potential duration (APD), mainly by shortening Purkinje fiber APD. We conclude: that propafenone suppresses idioventricular rhythm in the intact dog, most likely by depressing Purkinje fiber automaticity; the depressant effect of propafenone on sinus nodal automaticity is evident only during cholinergic receptor blockade; and the antiarrhythmic properties of propafenone may include removal of APD disparity by selective shortening of Purkinje fiber and not of ventricular muscle APD.

Animals↗
PubMed1976

[Sleep in the young adult studied through automatic analysis of recordings].

Our laboratory sleep polygraphic recordings are all automatically scored by a scoring system previously described. The automatic scoring reliability has already been estimated by a comparison with visual scoring. Nevertheless, it was interesting to investigate whether the picture of sleep given by this system, of a precisely defined group of subjects, was very different from that obtained by visual scoring for similar subjects in other laboratories. Therefore, we compared the results given by automatic analysis in a group of normal subjects aged 20--29 years with the results of Williams et al. (1974) for subjects of the same age. We thus mixed on purpose three sources of difference: the studied population, the laboratory and its habits, and the technique of scoring the records. This comparison showed a clear difference in the total time of sleep for men and women. This time, longer in our conditions, depended certainly on subjects and on recording conditions more than on automatic scoring. Sleep and stage latencies were not significantly different by the two scoring techniques. A difference appeared for waking latency, longer in our findings, but probably resulting from the definition of this parameter. The number of sleep cycles and their average duration were not different in the two techniques. Concerning sleep stages, stage 3 was slightly overestimated and stage 4 underestimated by automatic scoring compared with visual scoring, while there was no marked difference for the other stages. Finally, a larger number of stages are detected by the machine than by the human eye, which is probably due to the fact that the latter neglects some transitions from one stage to another when they are not important with regard to the context. Thus, apart from some differences resulting from the definition of parameters, there is a very large analogy between visual and automatic results of sleep scoring. The only effects of the latter are a slightly different assessment of the ratio of stages 3 and 4, in favour of stage 3, a larger estimate of the number of sleep stages, and a slight underestimation of REM sleep.

Adult↗
PubMed1975

Cell counts in the human cerebral cortex using a traditional and an automatic method.

This study compares the results of cell counting in the human cerebral cortex by a traditional and an automatic procedure. Four blocks were taken from standard areas of each of 10 brains from individuals aged 18-95 years and showing no neurological abnormality. Sections from each block were counted by traditional and automatic methods, both of which are described. The traditional method used photomicrographs and the automatic procedure used the quantimet 720 Image Analysing Computer. The degree of reproducibility of each method was measured and the results are discussed and tabulated. Comparison are made of the total cell counts, and the counts of cells measuring greater than 20 um across. The results show a high level of correlation between the two procedures but the manual count yields higher number for total cells and smaller numbers for large cells than the automatic method. The reasons for these discrepancies are discussed and examples of the arterfacts which produce them are giver. Using the traditional method described the amount of meterial examined took about 4 months to study. The sane tissue can be assessed in 1 day using the automatic apparatus. The high speed and close correlation achieved by the automatic procedure makes it a valuable aid in quantitative cell studies in the central nervous system.

Cell Count↗
PubMed1993

An algorithm for automatic analysis of portal images: clinical evaluation for prostate treatments.

The aim of this study is to assess the clinical value of an algorithm for automatic analysis of portal images by measuring the method's performance in a clinical study of treatment of prostate cancer. The algorithm is based on chamfer matching and measures displacements of patients relative to prescribed radiation beam positions. In this paper we propose a method to quantify the mean standard deviation (MSD) of the performance of automatic analysis relative to the MSD of the performance of trained radiographers using the clinical data set only, i.e. without using additional phantoms or simulations. The clinical data set in this study consists of 99 regional AP prostate images of 15 different patients. To assess the performance the automatic analysis in relation to that of the human observers, we studied the results of the unsupervised automatic analysis, as well as the results of a less-trained human observer and a well-trained human observer assisted by the automatic analysis (in this combination, automatic analysis is done first and the result is modified by the well-trained observer if the observer does not agree). First, the intra-observer variations of the well-trained observer are measured by repetitive analysis of a small subset of the clinical data. The distribution of differences in analysis between two arbitrary observers is described by the chi 2 distribution, and is tabulated in literature. We define the agreement histogram of an observer O as an estimator for the chi 2 distribution between O and the well-trained human observer, parameterized by the ratio of the intra-observer variations of O and the well-trained observer.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed2006

Specific predictive power of automatic spider-related affective associations for controllable and uncontrollable fear responses toward spiders.

This study examined the predictive power of automatically activated spider-related affective associations for automatic and controllable fear responses. The Extrinsic Affective Simon Task (EAST; De Houwer, 2003) was used to indirectly assess automatic spider fear-related associations. The EAST and the Fear of Spiders Questionnaire (FSQ) were used to predict fear responses in 48 female students from Maastricht University with varying levels of spider fear. Results showed that: (i) the EAST best predicted automatic fear responses, whereas (ii) the FSQ best predicted strategic avoidance behavior. These results suggest that indirect measures of automatic associations may have specific predictive power for automatic fear responses.

Adult↗
PubMed2004

Automatic processing of self-regulation of slow cortical potentials: evidence from brain-computer communication in paralysed patients.

OBJECTIVE: Direct brain-computer communication utilizes self-regulation of brain potentials to select letters, words or symbols from a computer menu. Selection of letters or words with brain potentials requires simultaneous processing of several tasks such as production of certain brain potentials at predefined time points simultaneously with processing of presented letter strings. This study addresses the question of whether the self-regulation of slow cortical potentials (SCP) automatizes with practice and can thus be considered as a skill comparable to motor or cognitive skills. METHODS: Two nearly completely paralysed patients learned over several months to produce electrocortically negative and positive SCP by means of visual feedback. Improved performance and a reduction in performance variability were regarded as behavioural indicators for automaticity, while the topographic focalization of cortical activation was considered as a neurophysiological indicator for automaticity. Different indicators of automaticity were expected to covary along with practice. RESULTS: In patient 1, performance measured as the percentage of correct SCP shifts increased simultaneously with the topographic focalization of cortical activation. His performance became more stable with practice. For this patient the criteria for automaticity were all met. In patient 2, performance also improved, but his cortical activity became topographically less focal. His performance was less stable than that of patient 1. CONCLUSIONS: The present findings, albeit on only two subjects, provide preliminary evidence that SCP self-regulation may automatize with long-term practice and can therefore be considered a skill.

Adaptation, Psychological↗
PubMed2006

Fully automatic external defibrillators in acute care: Clinicians' experiences and perceptions.

BACKGROUND: Fully automatic external defibrillators (FAEDs) reduce the time to defibrillation [Martinez-Rubio A, Kanaan N, Borggrefe M, Block M, Makijarvi M, Fedele F, et al. Advances in treating in-hospital cardiac arrest: safety and effectiveness of a new automatic external cardioverter-defibrillator. J Am Coll Cardiol 2003;41(4):627-32; Mattioni T, Kanaan N, Riggio D, Bahu M, Lin D, Welch S, et al. Performance of an automatic external-cardioverter-defibrillator algorithm in the discrimination of supraventricular from ventricular tachycardia. Am J Cardiol 2003;91:1323-6] and improve outcomes [Martinez-Rubio A, Kanaan N, Borggrefe M, Block M, Makijarvi M, Fedele F, et al. Advances in treating in-hospital cardiac arrest: safety and effectiveness of a new automatic external cardioverter-defibrillator. J Am Coll Cardiol 2003;41(4):627-32]. There is, however, no guidance or standard about their use in the UK. This paper presents the results of a study, which explored clinicians' experiences and perceptions of using FAEDs in acute care in the UK. AIMS: This study sought to understand clinicians' experiences and perceptions of the use of FAEDs in acute care and their impact on decision making. METHODS: Using a qualitative approach, 43 nurses and four physicians were included in a trial of FAEDs in a Coronary Care Unit (CCU) and cardiology ward during 2004. Semi-structured interviews were conducted with nurses and physicians prior to and following the trial. Data were analysed using thematic analysis [Attride-Stirling J, Thematic networks: an analytic to research. Qual Res 2001;1(3):385-405]. RESULTS: Decision control, safety, a lack of confidence in the technology, previous experience and concerns about the psychological affect on patients affected clinicians' decision making and limited the use of the FAED. CONCLUSION: Despite reported benefits of the FAED [Martinez-Rubio A, Kanaan N, Borggrefe M, Block M, Makijarvi M, Fedele F, et al. Advances in treating in-hospital cardiac arrest: safety and effectiveness of a new automatic external cardioverter-defibrillator. J Am Coll Cardiol 2003;41(4):627-32; Mattioni T, Kanaan N, Riggio D, Bahu M, Lin D, Welch S, et al. Performance of an automatic external-cardioverter-defibrillator algorithm in the discrimination of supraventricular from ventricular tachycardia. Am J Cardiol 2003;91:1323-26], personal and contextual issues affected the clinicians' decision making. More and better understanding about how FAEDs and their context of use may challenge established practice is required in order that it is utilised in the most effective way.

Attitude of Health Personnel↗
PubMed2004

The effect of mismatched recording conditions on human and automatic speaker recognition in forensic applications.

In this paper, we analyse mismatched technical conditions in training and testing phases of speaker recognition and their effect on forensic human and automatic speaker recognition. We use perceptual tests performed by non-experts and compare their performance with that of a baseline automatic speaker recognition system. The degradation of the accuracy of human recognition in mismatched recording conditions is contrasted with that of the automatic system under similar recording conditions. The conditions considered are of public switched telephone network (PSTN) and global system for mobile communications (GSM) transmission and background noise. The perceptual cues that the human subjects use to perceive differences in voices are studied along with their importance in different conditions. We discuss the possibility of increasing the accuracy of automatic systems using the perceptual cues that remain robust to mismatched conditions. We estimate the strength of evidence for both humans and automatic systems, calculating likelihood ratios using the perceptual scores for humans and the log-likelihood scores for automatic systems.

Bayes Theorem↗
PubMed2005

Collecting information on the quality of prescribing in primary care using semi-automatic data extraction from GPs' electronic medical records.

OBJECTIVES: To evaluate a semi-automatic data extraction from the electronic medical record (EMR) of general practitioners (GPs) through a comparison with a paper sheets data collection simultaneously used in a primary care research project on the quality of prescribing for osteoarthritis in the elderly. SUBJECTS: One hundred and fifty-two GPs using five different EMR-software systems participated with the semi-automatic data extraction from the EMR and 233 GPs collected data with paper registration sheets. METHODS: The proportion of patients with respectively a drug prescription, paracetamol, a non-steroidal anti-inflammatory drug (NSAID) and ibuprofen were compared between the semi-automatic extraction and the paper data collection and among the EMR-software systems. RESULTS: Using the semi-automatic data extraction, a significantly lower proportion of patients on drugs was obtained compared to the paper data collection (adjusted OR: 0.31; 95% CI 0.25-0.39). However, the proportion of patients on a specific type of drug was comparable. Within the results from the semi-automatic extraction, the results were heterogeneous among the different EMR-software systems. CONCLUSIONS: The semi-automatic data extraction with multiple EMR-software systems proposed in this study seems suitable for quality of prescribing assessment in primary care. However, it may be less reliable when only a single EMR-software is used.

Aged↗
PubMed2006

Automatic detecting indicators for quality of health information on the Web.

OBJECTIVES: To automatically evaluate the quality of health information on the Internet, we presents a method for detecting indicators for quality of health information. METHODS: An automatic indicator detection tool (AIDT) was developed in the following steps: (1) 18 initial technical criteria were chosen; (2) multiple measurable indicators were defined for each criterion; (3) these measurable indicators on the Web pages were automatically detected by a computer program; (4) the detectable indicators were selected for each criterion based on detection accuracy and occurrence frequency, and detecting criteria on Web pages; (5) AIDT was developed based on the detectable indicators and criteria. The efficiency of detection tool was measured by recall and precision of detecting criteria. The performance of AIDT was tested using three data sets. RESULTS: AIDT with validated detectable indicators can reach 93% recall and 98% precision on these data sets. AIDT can automatically and correctly detect measurable criteria on Web pages. CONCLUSIONS: Automatic detecting indictors for quality of health information is feasible and effective. Using an automatic detecting tool is a promising method for identifying quality criteria of health information, and eventually it can be used to develop instruments for evaluating the quality of health Websites.

Automation↗
PubMed2003

[Protocol to evaluate automatic continuous positive airway pressure. Assessment of the usefulness of the Autoset-T device to determine optimal pressure for treating sleep apnea/hypopnea syndrome].

INTRODUCTION: Given the high prevalence of sleep apnea/hypopnea syndrome (SAHS) and great demand for conventional polysomnography (PSG) and long waiting lists, alternative means for diagnosing SAHS and titrating continuous positive airway pressure (CPAP) are needed. Automatic CPAP may play a role in meeting the last objective, not only for treatment but also for suggesting the optimum CPAP setting. OBJECTIVES: a) To define a protocol to assess the functioning of an automatic CPAP device by means of a mechanical model; b) to determine the behavior of automatically adjusted CPAP during PSG; c) to define the usefulness of automatic CPAP for indicating optimal CPAP pressure for patients with SAHS; d) to evaluate the efficacy of the automatically indicated pressure setting against conventional PSG. METHODS: Four protocols were carried out using the Autoset-T (AT) device. 1. Apneas, hypopneas, flow limitation, snoring and normal flow were simulated in a laboratory using a mechanical model in order to check AT functioning. 2. The behavior of the automatically adjusted CPAP was observed in real time during PSG in 12 patients with severe SAHS. 3. The agreement of CPAP titrated with the AT and with PSG was checked in a group of 39 patients with SAHS. 4. The efficacy of the CPAP pressure recommended by the AT was checked by PSG in a group of 14 patients with SAHS. RESULTS: With the AT, CPAP increased rapidly in response to apneas or snoring in the mechanical model and during conventional PSG; it took only a mean 2.8 3.1 min to rise from a baseline pressure of 4 cm H2O to a near-optimum pressure of 11 1 cm H2O. Once normal flow was reached CPAP slowly decreased, responding with great sensitivity to the slightest abnormality, especially snoring, but not changing in response to certain types of flow limitation. The pressure read visually on the AT was similar to the one recommended by PSG in most of the 39 patients (71%). The PSG performed after one month of using AT-recommended CPAP titration confirmed that the number of apneas, hypopneas (apnea/hypopnea index 6(1) and arousals (8 2) was normal for these SAHS patients. CONCLUSIONS: The AT increases pressure rapidly in the presence of respiratory events and maintains a normal breathing pattern in most patients. Visual reading of the AT pressure allows correct identification of the optimal CPAP setting for SAHS treatment.

Aged↗
PubMed2003

A robust and automatic method for evaluating accuracy in 3-D ultrasound-based navigation.

We present a robust and automatic method for evaluating the 3-D navigation accuracy in ultrasound (US) based image-guided systems. The method is based on a precisely built and accurately measured phantom with several wire crosses and an automatic 3-D template matching by correlation algorithm. We investigated the accuracy and robustness of the algorithm and also addressed optimization of algorithm parameters. Finally, we applied the method to an extensive data set from an in-house US-based navigation system. To evaluate the algorithm, eight skilled observers identified the same wire crosses manually and the average over all observers constitutes our reference data set. We found no significant differences between the automatic and the manual procedures; the average distance between the point sets for one particular volume (27 point pairs) was 0.27 +/- 0.17 mm. Furthermore, the spread of the automatically determined points compared with the reference set was lower than the spread for any individual operator. This indicates that the automatic algorithm is more accurate than manual determination of the wire-cross locations, in addition to being faster and nonsubjective. In the application example, we used a set of 35 3-D US scans of the phantom under various acquisition configurations. The US frequency was 6.7 MHz and the average target depth was 6 cm. The accuracy, represented by the mean distance between automatically-determined wire-cross locations and physically measured locations, was found to be 1.34 +/- 0.62 mm.

Algorithms↗
PubMed1998

MRI measurement of brain tumor response: comparison of visual metric and automatic segmentation.

An automatic magnetic resonance imaging (MRI) multispectral segmentation method and a visual metric are compared for their effectiveness to measure tumor response to therapy. Automatic response measurements are important for multicenter clinical trials. A visual metric such as the product of the largest diameter and the largest perpendicular diameter of the tumor is a standard approach, and is currently used in the Radiation Treatment Oncology Group (RTOG) and the Eastern Cooperative Oncology Group (EGOG) clinical trials. In the standard approach, the tumor response is based on the percentage change in the visual metric and is categorized into cure, partial response, stable disease, or progression. Both visual and automatic methods are applied to six brain tumor cases (gliomas) of varying levels of segmentation difficulty. The analyzed data were serial multispectral MR images, collected using MR contrast enhancement. A fully automatic knowledge guided method (KG) was applied to the MRI multispectral data, while the visual metric was taken from the MRI films using the T1 gadolinium enhanced image, with repeat measurements done by two radiologists and two residents. Tumor measurements from both visual and automatic methods are compared to "ground truth," (GT) i.e., manually segmented tumor. The KG method was found to slightly overestimate tumor volume, but in a consistent manner, and the estimated tumor response compared very well to hand-drawn ground truth with a correlation coefficient of 0.96. In contrast, the visually estimated metric had a large variation between observers, particularly for difficult cases, where the tumor margins are not well delineated. The inter-observer variation for the measurement of the visual metric was only 16%, i.e., observers generally agreed on the lengths of the diameters. However, in 30% of the studied cases no consensus was found for the categorical tumor response measurement, indicating that the categories are very sensitive to variations in the diameter measurements. Moreover, the method failed to correctly identify the response in half of the cases. The data demonstrate that automatic 3D methods are clearly necessary for objective and clinically meaningful assessment of tumor volume in single or multicenter clinical trials.

Adult↗
PubMed1999

The lifetime of automatic semantic priming effects may exceed two seconds.

The N400 component of event-related potentials (ERPs) was obtained in a modified version of the Neely [J.H. Neely, Semantic priming and retrieval from lexical memory: Roles of inhibitionless spreading activation and limited-capacity attention, Journal of Experimental Psychology: General, Vol. 106 (1977), pp. 226-254.] paradigm which permits unconfounding of semantic priming effects due to automatic and attentional processes. It was found that a short stimulus onset asynchrony (SOA) of 250 ms between the prime and the target was associated with automatic but not expectancy effects on the amplitude of N400. At a long SOA of 2000 ms between prime and target, semantic priming effects on N400 were obtained associated with both automatic and expectancy processes. Moreover, there was no significance difference in the magnitude of the automatic effects at the two SOAs, suggesting that automatic processing had not decayed within the 2000 ms interval between the prime and target. The results support the two-processing interpretation of semantic priming advanced by Posner and Synder [M.I. Posner, C.R.R. Snyder, Attention and cognitive control, in: R.L. Solso (Ed.), Information Processing and Cognition: The Loyola Symposium, Erlbaum, Hillsdale, NJ (1975).] and concur with the results of Neely [J.H. Neely, Semantic priming and retrieval from lexical memory: Roles of inhibitionless spreading activation and limited-capacity attention, Journal of Experimental Psychology: General, Vol. 106 (1977), pp. 226-254], with the exception of indicating a longer persistence of automatic processes.

Adult↗
PubMed1997

Evaluation of an automatic-mode image processing method in chest computed radiography.

RATIONALE AND OBJECTIVES: The automatic image processing mode of the storage phosphor computed radiography system was evaluated. MATERIALS AND METHODS: A dedicated chest unit designed for erect view was used to examine a chest phantom. Lucite plates 1, 2, and 3 cm thick that conformed to the shape of the lung were attached to the phantom, and images were obtained in automatic and manual image processing modes. The changes in the optical density of the lung, rib, and heart and the changes in contrast were measured. The degree of diffuse opacity due to the plates and the visibility of superimposed simulated nodular and honeycomb opacities were evaluated. RESULTS: The decrease in optical density and contrast caused by increasing thickness of the Lucite plates was less pronounced in the automatic mode compared with the manual mode. When plates were placed only on the right lung, the optical density and the contrast on the contralateral side either increased or remained unchanged with the automatic mode. The degree of diffuse opacity was rated higher in the manual mode, and the visibility of superimposed simulated opacities was considered relatively constant in the automatic mode. CONCLUSION: The automatic image reading mode used in the computed radiography chest system may mask the detection of abnormalities such as diffuse homogeneous lung opacity.

Evaluation Studies as Topic↗
PubMed1998

Automatic analysis of the in vitro micronucleus test on V79 cells.

The in vitro micronucleus test is a well established test for early screening of new chemical entities in industrial toxicology. For assessing the clastogenic or aneugenic potential of a test compound, micronucleus induction in cells has been shown repeatedly to be a sensitive and specific parameter. As a measure for numerical and structural chromosome aberrations, the in vitro micronucleus test consists of determining the frequency of micronucleated cells in a representative fraction of cells in a culture. So far, manual counting has been the only method for evaluating microscopic V79 Chinese hamster cell preparations. To replace this tedious and time consuming procedure, a fully automatic system for micronucleus scoring in V79 cells by image analysis has been developed and introduced into the routine genotoxicity screening of drug candidates. The comparison of manual and automatic micronucleus analysis showed a high degree of concordance between the results obtained by the two techniques. For concentration series of cyclophosphamide (CP) and ethyl-methanesulphonate (EMS) as test compounds, the frequency of erroneously missed micronuclei through automatic scoring proved to be below 15% in comparison with manual scoring. Generally, false positive micronucleus decisions could be controlled easily by fast and simple relocation of the automatically detected patterns. The possibility to analyze 24 slides within 1 day by fully automatic overnight analysis and the high reproducibility of the results make automatic image processing a powerful tool for the in vitro micronucleus analysis.

Animals↗
PubMed2003

Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients.

BACKGROUND AND OBJECTIVE: Automatic tube compensation has been designed as a new ventilatory mode to compensate for the non-linear resistance of the endotracheal tube. The study investigated the effects of automatic tube compensation compared with breathing through a T-piece or pressure support during a trial of spontaneous breathing used for weaning patients from mechanical ventilation of the lungs. METHODS: Twelve patients were studied who were ready for weaning after prolonged mechanical ventilation (10.2 +/- 8.4 days) due to acute respiratory failure. Patients with chronic obstructive pulmonary disease were excluded. Thirty minutes of automatic tube compensation were compared with 30 min periods of 7 cmH2O pressure support and T-piece breathing. Breathing patterns and workload indices were measured at the end of each study period. RESULTS: During T-piece breathing, the peak inspiratory flow rate (0.65 +/- 0.20 L s(-1)) and minute ventilation (8.9 +/- 2.7L min(-1)) were lower than during either pressure support (peak inspiratory flow rate 0.81 +/- 0.25 L s(-1) minute ventilation 10.2 +/- 2.3 L min(-1), respectively) or automatic tube compensation (peak inspiratory flow rate 0.75 +/- 0.26L s(-1); minute ventilation 10.8 +/- 2.7 L min(-1)). The pressure-time product as well as patients' work of breathing were comparable during automatic tube compensation (pressure-time product 214.5 +/- 104.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)) and T-piece breathing (pressure-time product 208.3 +/- 121.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)), whereas pressure support resulted in a significant decrease in workload indices (pressure-time product 121.2 +/- 64.1 cmH2O s(-1) min(-1), patient work of breathing 0.7 +/- 0.4 J L(-1)). CONCLUSIONS: In weaning from mechanical lung ventilation, patients' work of breathing during spontaneous breathing trials is clearly reduced by the application of pressure support 7 cmH2O, whereas the workload during automatic tube compensation corresponded closely to the values during trials of breathing through a T-piece.

Adult↗
PubMed1985

Automatic and attentional components in perception of shape-at-a-slant.

In perceiving shape-at-a-slant it is assumed that a sequence of operations is executed. The aim of these experiments was to determine the extent to which execution of these operations requires allocation of attention. Three hypotheses were considered: zero automaticity--that all of the operations require attention; partial automaticity--that the operations culminating in a representation of projective shape and slant-in-depth are automatic while the combinatorial operations culminating in a distally correlated shape require attention; full automaticity--that the entire sequence of operations is automatic, proceeding without allocation of attention. To decide among these hypotheses, subjects performed forced-choice shape recognition tests under two conditions: In the shape-directed condition subjects were motivated to process shape. In the numerosity-directed condition subjects were motivated to direct attention to discrimination of numerosity, thereby causing attention to be diverted from processing of shape. Examination of the pattern of choices on the recognition test showed results that conformed best to the hypothesis of partial automaticity.

Attention↗