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At least 1,009 records · Page 56Linked to original sources
PubMed2003

[The effect of time on the perception of dyspnea following inhaled long-acting bronchodilator].

STUDY OBJECTIVES: To assess the effect of time on the change in the perception of dyspnea (POD) following inhalation of long-acting bronchodilator. PATIENTS AND METHODS: Spirometry and the POD were measured in 32 asthmatic patients, with moderate asthma, before and following inhalation of placebo, and salmeterol. The POD was measured while breathing against progressive loads, using a visual analogue scale (VAS). RESULTS: The highest FEV1 levels and the lowest POD were measured one hour after salmeterol inhalation. Although the mean FEV1 remained close to its peak value for at least six hours following the inhalation of salmeterol, there was a gradual statistically significant increase in the POD. CONCLUSIONS: Following inhalation of long-acting bronchodilator (LABD) there is relationship between the increase in the FEV1 and the decrease in POD. With time there is a gradual increase in the perception of dyspnea regardless of the FEV1.

Administration, Inhalation↗
PubMed2002

Time course of perception and decision making during mammographic interpretation.

OBJECTIVE: This article describes the time course of lesion detection on digital mammograms using data about both eye position and decision time to compare performance between experienced mammographers and trainees. Research indicates that a longer decision time works against performance in the interpretation of chest radiographs because the likelihood of error is increased, particularly for trainees. Is this relation between decision time and performance also true for interpreting mammograms? Is there an optimal decision time-performance trade-off for detecting breast lesions? MATERIALS AND METHODS: Six radiology trainees (experience, 302-976 cases) and three mammographers (experience, 3000-5000 cases per year) reviewed 40 test cases. Each test case was represented by two mammograms that showed different views of the same breast. Twenty breasts contained suspicious lesions, and 20 were lesion-free. An interactive computer display system with an eye-head tracker measured the timing of decisions, where visual attention was directed, and how much time was spent fixating on a region of interest for each decision. Eye position was monitored during an initial-decision phase, and decision times were measured throughout a final-decision phase during which suspicious lesions recognized initially were interpreted and localized. Performance was analyzed using localization receiver operating characteristic curves. RESULTS: The time course of interpreting mammograms is similar to that for interpreting chest radiographs. Mammographers detected 71% of the true lesions within 25 sec, and trainees detected 46% within 40 sec. Both a fixation dwell time of 1000 msec and a high level of confidence in the decision were associated with the detection of true lesions for the mammographers but not for the trainees. CONCLUSION: Mammographers detected most breast lesions by global recognition within 25 sec, but trainees took more time. Prolonging one's search beyond the global recognition phase yielded few new lesions and increased the risk of error.

Breast Neoplasms↗
PubMed1998

Obligatory "expectations" of expressive timing induced by perception of musical structure.

Previous research has shown that, in a task requiring the detection of local deviations from mechanically precise timing in music, the relative detectability of deviations in different positions is closely related to the typical expressive timing pattern musicians produce when playing the music. This result suggests that listeners expect to hear music expressively timed and compensate for the absence of expressive timing. Three new detection experiments shed additional light on the nature of these timing expectations in musically trained listeners. Experiment 1 shows that repeated exposure to an atypically (but not unmusically) timed performance leaves listeners' timing expectations unaffected. Experiment 2 demonstrates that the expectations do not manifest themselves when listeners merely imagine the music in synchrony with a click track. Experiment 3, however, shows that the timing expectations are fully operational when the click track is superimposed on the music. These results reveal timing "expectations" to be an obligatory consequence of the ongoing auditory perception of musical structure.

Adult↗
PubMed1996

General practitioner perceptions of surgical waiting times.

This study explored general practitioners' (GP) perceptions of waiting times and the importance of these perceptions in choosing a surgeon. A randomly selected sample of GPs in the Hunter Area of New South Wales, Australia, provided information prospectively on patients referred to a surgeon. The results indicated that GPs feel a lack of private health insurance makes only a small difference in waiting time to see a surgeon but a large difference in the waiting time for an operation. Additionally, GPs consider that sizeable numbers of patients will wait longer than they consider reasonable for surgical consultations and procedures. However, perceptions of waiting times do not appear to have a major influence on the choice of surgeon.

Attitude of Health Personnel↗
PubMed1983

Rhythm and time in the perception of Down's syndrome children.

This investigation attempts to examine a sense of rhythm in relation to levels of response to rhythmic stimuli in normal children and mentally handicapped children, particularly children with Down's syndrome. Ten Down's syndrome (average CA: 158 months, average MA: 43 months), ten other mentally handicapped children (average CA: 147 months, average MA: 44 months), and ten normal children (average CA: 50 months, average MA: 46 months) were required to listen to a rhythm and to shadow certain rhythms by tapping them out simultaneously with the stimuli. Three different rhythms of increasing complexity were used. After a practice session, responses were collected from subjects using a tapping device; these were recorded on a computer. Results obtained in all aspects of the tests were very similar in both normal and Down's syndrome groups. The other mentally handicapped children were considerably weaker than the other two groups. It is suggested that at this level there is no difference between Down's syndrome and normal children of the same mental age in rhythmic discrimination. Differences lie between Down's syndrome and other mentally handicapped children and this comparison could account for the attribution to Down's syndrome children of a higher than normal level of musical skills.

Adolescent↗
PubMed2006

Estimation of the timing of human visual perception from magnetoencephalography.

To explore the timing and the underlying neural dynamics of visual perception, we analyzed the relationship between the manual reaction time (RT) to the onset of a visual stimulus and the time course of the evoked neural response simultaneously measured by magnetoencephalography (MEG). The visual stimuli were a transition from incoherent to coherent motion of random dots and an onset of a chromatic grating from a uniform field, which evoke neural responses in different cortical sites. For both stimuli, changes in median RT with changing stimulus strength (motion coherence or chromatic contrast) were accurately predicted, with a stimulus-independent postdetection delay, from the time that the temporally integrated MEG response crossed a threshold (integrator model). In comparison, the prediction of RT was less accurate from the peak MEG latency, or from the time that the nonintegrated MEG response crossed a threshold (level detector model). The integrator model could also account for, at least partially, intertrial changes in RT or in perception (hit/miss) to identical stimuli. Although we examined MEG-RT relationships mainly for data averaged over trials, the integrator model could show some correlations even for single-trial data. The model predictions deteriorated when only early visual responses presumably originating from the striate cortex were used as the input to the integrator model. Our results suggest that the perceptions for visual stimulus appearances are established in extrastriate areas [around MT (middle temporal visual area) for motion and around V4 (fourth visual area) for color] approximately 150-200 ms before subjects manually react to the stimulus.

Adult↗
PubMed2005

Visual motion perception at the time of saccadic eye movements and its relation to spatial mislocalization.

The same retinal image motion can be produced by a variety of combinations of eye and target motion. In natural conditions, extraretinal information disambiguates retinal information for motion perception. By controlling the timing of visual motion with respect to saccades, it was possible to appraise the roles for motion perception of the signal related to saccades occurring in the vicinity of visual motion. When a visual motion was seen before or after a saccade, its perceived direction was biased in the direction opposite to the saccade. The magnitude of the bias depended on the timing of the visual motion with respect to the saccade and the meridian of the visual motion. The bias appears to be independent of the deformation of visual space reported to occur before and after saccades.

Humans↗
PubMed1998

Flexible magnets are not effective in decreasing pain perception and recovery time after muscle microinjury.

OBJECTIVE: To assess the therapeutic effects of flexible magnets on pain perception, intramuscular swelling, range of motion, and muscular strength in individuals with a muscle microinjury. DESIGN AND SETTING: This experiment was a single-blind, placebo study using a repeated-measures design. Subjects performed an intense exercise protocol to induce a muscle microinjury. After pretreatment measurements were recorded, subjects were randomly assigned to an experimental (magnet), placebo (imitation magnet), or control (no magnet) group. Posttreatment measurements were repeated at 24, 48, and 72 hours. SUBJECTS: Forty-five healthy subjects participated in the study. MEASUREMENTS: Subjects were measured repeatedly for pain perception, upper arm girth, range of motion, and static force production. Four separate univariate analyses of variances were used to reveal statistically significant mean (+/-SD) differences between variables over time. Interaction effects were analyzed using Scheffe post hoc analysis. RESULTS: Analysis of variance revealed no statistically significant (P > .05) mean differences between conditions for any dependent pretreatment and posttreatment measurements. No significant interaction effects were demonstrated between conditions and times. CONCLUSIONS: No significant therapeutic effects on pain control and muscular dysfunction were observed in subjects wearing flexible magnets.

Journal Article↗
PubMedDate not supplied

Validation of human behavioral tests using ethanol as a CNS depressant model.

This study evaluated the sensitivity of a battery of tests proposed for use in determining the depressant effects of chemicals on human central nervous system (CNS) function. The first step in the development of such tests was to determine if the tests could detect the effects produced by a known CNS depressant, ethanol. Five behavioral tests, digit span memory, simple reaction time, tachistoscopic perception, flicker fusion and anticipation timing (velocity estimation) were evaluated to determine their sensitivity to the effects of ethanol at blood levels between 0.05-0.06%. Thirty-one adult male volunteers received 0 and 1.4 ml 100 proof vodka/kg body weight according to a double-blind crossover design. Tests were conducted before treatment and between 30 and 70 minutes after an ethanol or control drink was ingested. Multivariate analysis of variance (MANOVA), using composite scores representing the individual tests, indicated that the battery as a whole detected statistically significant ethanol effects. Repeated measures analysis of variance (ANOVA) comparing performance after drinking ethanol to control performance on each of the individual tests indicated a significant decrement in reaction time, tachistoscopic perception and anticipation timing.

Adult↗
PubMed1987

Paramedic perception of elapsed field time.

An independent observer was placed with city paramedic teams to: a) record exactly how long emergency field procedures take; and b) determine the paramedic's perception of elapsed field time. One hundred eighteen runs were monitored; 33% required advanced life support skills, and 36% were for trauma. The response time (mean +/- S.E.M.) averaged 5.4 +/- 0.26 min, scene time 11.2 +/- 0.54 min, and transport time 9.5 +/- 0.86 min. The average time required to perform scene procedures ranged from 1.5 +/- 0.5 min for defibrillation to 5.0 +/- 0.47 min to start an IV. Paramedic perception of elapsed time for the entire run varied from the actual time by an average absolute value of 20%, with the greatest errors occurring in scene time estimates. Paramedics tended to overestimate elapsed time during short runs, and underestimate time on long runs. This report provides realistic field procedure times for urban paramedics. Distortion of time perception in the field environment emphasizes the need for strict medical control.

Allied Health Personnel↗