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Results for “Task Shifting”

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At least 613 records · Page 34Linked to original sources

PubMed2002

Critical period for cross-modal plasticity in blind humans: a functional MRI study.

The primary visual cortex (V1) in congenitally blind humans has been shown to be involved in tactile discrimination tasks, indicating that there is a shift in function of this area of cortex, but the age dependency of the reorganization is not fully known. To investigate the reorganized network, we measured the change of regional cerebral blood flow using 3.0 Tesla functional MRI during passive tactile tasks performed by 15 blind and 8 sighted subjects. There was increased activity in the postcentral gyrus to posterior parietal cortex and decreased activity in the secondary somatosensory area in blind compared with sighted subjects during a tactile discrimination task. This suggests that there is a greater demand for shape discrimination processing in blind subjects. Blind subjects, irrespective of the age at onset of blindness, exhibited higher activity in the visual association cortex than did sighted subjects. V1 was activated in blind subjects who lost their sight before 16 years of age, whereas it was suppressed in blind subjects who lost their sight after 16 years of age during a tactile discrimination task. This suggests that the first 16 years of life represent a critical period for a functional shift of V1 from processing visual stimuli to processing tactile stimuli. Because of the age-dependency, V1 is unlikely to be the "entry node" of the cortex for the redirection of tactile signals into visual cortices after blinding. Instead, the visual association cortex may mediate the circuitry by which V1 is activated during tactile stimulation.

Adult↗

PubMed2001

Temporal coordination of the human head and eye during a natural sequential tapping task.

The 'natural' temporal coordination of head and eye was examined as four subjects tapped a sequence of targets arranged in 3D on a worktable in front of them. The head started to move before the eye 48% of the time. Both the head and eye started to move 'simultaneously' (within 8 ms of each other) 37% of the time. The eye started to move before the eye only 15% of the time. Gaze-shifts required to perform the tapping task were relatively large, 68% of them were between 27 degrees and 57 degrees. Gaze-shifts were symmetrical. There were almost as many lefts as rights. Very little inter- or intra-subject variability was observed. These results were not expected on the basis of prior studies of head/eye coordination performed under less natural conditions. They also were not expected given the results of two rather similar, relatively natural, prior experiments. We conclude that more observations under natural conditions will have to be made before we understand why, when and how human beings coordinate head and eyes as they perform everyday tasks in the work-a-day world.

Eye Movements↗

PubMed2006

Shifts in doctor-patient communication between 1986 and 2002: a study of videotaped general practice consultations with hypertension patients.

BACKGROUND: Departing from the hypotheses that over the past decades patients have become more active participants and physicians have become more task-oriented, this study tries to identify shifts in GP and patient communication patterns between 1986 and 2002. METHODS: A repeated cross-sectional observation study was carried out in 1986 and 2002, using the same methodology. From two existing datasets of videotaped routine General Practice consultations, a selection was made of consultations with hypertension patients (102 in 1986; 108 in 2002). GP and patient communication was coded with RIAS (Roter Interaction Analysis System). The data were analysed, using multilevel techniques. RESULTS: No gender or age differences were found between the patient groups in either study period. Contrary to expectations, patients were less active in recent consultations, talking less, asking fewer questions and showing less concerns or worries. GPs provided more medical information, but expressed also less often their concern about the patients' medical conditions. In addition, they were less involved in process-oriented behaviour and partnership building. Overall, these results suggest that consultations in 2002 were more task-oriented and businesslike than sixteen years earlier. CONCLUSION: The existence of a more equal relationship in General Practice, with patients as active and critical consumers, is not reflected in this sample of hypertension patients. The most important shift that could be observed over the years was a shift towards a more businesslike, task-oriented GP communication pattern, reflecting the recent emphasis on evidence-based medicine and protocolized care. The entrance of the computer in the consultation room could play a role. Some concerns may be raised about the effectiveness of modern medicine in helping patients to voice their worries.

Adult↗

PubMed2006

A prospective observational study of the effect of night duty on the cognitive function of anaesthetic registrars.

The issue of fatigue in hospital medical staff represents a potential health and safety risk to both staff and patients, and is receiving worldwide interest. We aimed to characterize the cognitive performance of anaesthetic registrars before and after a series of night shifts. We enrolled nine full-time anaesthetic trainees in an Australian adult tertiary-referral hospital. We conducted a cross-over observational study which tested cognitive performance in participants before and after seven consecutive night shifts and compared this with performance before and after seven consecutive day shifts. Cognitive function was measured using a computerized assessment tool. Participants completed a mean of 62.5% of the requested testing (seven participants completed 87%). There was no significant change in performance before or after any day shift, nor at the commencement of each night shift. There was near perfect accuracy in performance in all tests at all times. There was a statistically significant deterioration in speed of performance for detection and identification tasks at the end of night shift as the week progressed. Anaesthetic registrars demonstrate a significant decline in cognitive performance after a series of night shifts.

Anesthesia↗

PubMed1990

A clockwork nursing unit. Analyzing how nurses spend their time is the first step toward improving productivity.

Until recently, productivity analysis has been a relatively underdeveloped tool in nursing. As healthcare costs continue their upward spiral, however, managers have been pressured to measure and evaluate nursing productivity. The right combination of efficiency and effectiveness is the key to optimal productivity. Nursing can be efficient but highly ineffective and thus of little value to the patient; conversely, nursing can be effective and valuable, but grossly inefficient. To determine a nursing unit's level of productivity, managers can keep a daily record of the number of nursing hours per patient day. When the record indicates too many ineffective or inefficient days, an analysis of how nurses use their time can help solve the problem. The first step is such an analysis is to have management engineering or the nursing staff itself collect data on time spent per task. Once these data are collected, they can be analyzed by shift (for the entire hospital), by individual unit, by task category, etc. With this information in view, managers can ask key questions to help pinpoint areas where efficiency might be improved.

Arizona↗

PubMed2001

Executive control of cognitive processes in task switching.

In 4 experiments, participants alternated between different tasks or performed the same task repeatedly. The tasks for 2 of the experiments required responding to geometric objects in terms of alternative classification rules, and the tasks for the other 2 experiments required solving arithmetic problems in terms of alternative numerical operations. Performance was measured as a function of whether the tasks were familiar or unfamiliar, the rules were simple or complex, and visual cues were present or absent about which tasks should be performed. Task alternation yielded switching-time costs that increased with rule complexity but decreased with task cuing. These factor effects were additive, supporting a model of executive control that has goal-shifting and rule-activation stages for task switching. It appears that rule activation takes more time for switching from familiar to unfamiliar tasks than for switching in the opposite direction.

Cognition↗

PubMedDate not supplied

Flexibility, inhibition, and planning: frontal dysfunctioning in schizophrenia.

Neuropsychological tests known to reveal abnormalities in patients with frontal lobe damage were used to explore cognitive function in 20 chronic schizophrenic patients. Eleven control subjects, matched on age and NLV-IQ (NLV is the Dutch version of the NART) were also tested. No impairments of planning ability were found on either the Action Program test or the Zoomap test, both subtests from the BADS (Behavioural Assessment of the Dysexecutive Syndrome). No abnormalities were apparent on tests of reactive flexibility, measured by task-switching and by the Rule Shift Cards test, also a subtest of the BADS. Patients with schizophrenia, however, had significantly greater difficulty in inhibiting irrelevant information and in generating words in a verbal fluency task, a measure of spontaneous flexibility.

Adult↗

PubMed1981

Ergonomic aspects of sport and recreation.

Human factors engineering or ergonomics originated in military technology from the team-work of engineers and specialists in the human sciences. The central focus is on the human operator upon whom the task and environment impose specific loadings. Intransigence of task demands in sport tends to shift emphasis to training and selection. Heredity seems to play the more important role in the evolution of the champion athlete. An integrated interdisciplinary approach is advocated in assessing task demands and individual capacity to meet them. Improving equipment and facility design promotes safety and performance efficiency. Environmental stresses may be simulated in laboratory conditions to provide opportunity for prior adaptation. Stresses associated with urbanized civilization present novel risks to social health. Quality of life can be enhanced from an ergonomics input into the design of sports facilities and exercise programmes and their subsequent monitoring.

Aerobiosis↗

PubMed2004

Evidencing inhibitory deficits in Alzheimer's disease through interference effects and shifting disabilities in the Stroop test.

To investigate the contribution of inhibitory deficits in the deterioration of executive function abilities in Alzheimer's disease (AD), a modified version of the Stroop test was submitted to 44 AD patients and 44 elderly controls. Half of the subjects performed successively the Interference Stroop task, the two control tasks and the Reverse Stroop task, and half performed the Reverse Stroop task, the control tasks and finally the Interference Stroop task. This experimental design allowed to assess inhibitory deficits by measuring classical interference effects but also by measuring the ability to shift between tasks instructions. Results confirmed AD patients' difficulty in suppressing the automatic response of reading in the Interference Stroop task. Moreover, AD patients presented worsened performances in the Interference task when administered after the Reverse task, and a Reverse Stroop effect was found in the patients revealing their difficulty in suppressing a previously relevant rule in order to learn a new one.

Aged↗

PubMed1998

Effects of alternating 8- and 12-hour shifts on sleep, sleepiness, physical effort and performance.

OBJECTIVES: The aim of the present study was to compare 12-hour shifts during weekends with 8-hour shifts during weekdays with respect to sleep, sleepiness, physical effort, and performance. METHODS: Thirty-one subjects at a power plant participated. Sleep, sleepiness, and physical effort were measured with a diary. About half of the subjects carried out a reaction-time test during both 8- and 12-hour morning and night shifts. The remaining subjects carried out a vigilance task. RESULTS: Sleepiness was higher and physical effort lower on the 12-hour night shift than on the 8-hour night shift. However, the subjects who had the same level of physical effort on 8- and 12-hour night shifts did not differ with respect to sleepiness. During the 12-hour morning shift, sleepiness was lower and the sleep length was longer than on the 8-h morning shift. The subjects who had the same amount of sleep for 8- and 12-hour morning shifts showed no difference in sleepiness. Sleep did not differ between 8- and 12-hour night shifts. There was no difference between 8- and 12-hour shifts with respect to performance. CONCLUSIONS: It was suggested that the difference in sleepiness between 8- and 12-hour shifts is related to differences in sleep length for the morning shift, and to differences in physical effort for the night shift, rather than to shift duration. Thus the most likely conclusion is that 12-hour shifts do not cause increased sleepiness or impaired performance or disturbed sleep.

Adult↗

PubMed1998

A multidimensional evaluation of fire fighter training for hazardous materials response: first results from the IAFF Program.

The International Association of Fire Fighters (IAFF) course on hazardous materials training for first responders is described together with an evaluation plan that includes multiple levels of assessment. Trainee appraisals of the course, shifts in their ratings of task competencies, gains in knowledge quiz scores, and self-reports on actions reflecting lessons learned from the course are among the measures used. Evaluations of courses given in several city fire departments found more than 60% of trainee judgments of course quality and utility to be highly favorable, along with significant post-course improvements in their competency ratings and quiz scores. Follow-up interviews with samples of trainees also suggested more self-protective behaviors and preventive actions being taken with regard to alarms and risks of hazardous materials exposures. However, cross-comparing the results for the various evaluation measures gave only limited support to a popular evaluation model that hypothesized that they would be interdependent. Limitations in appreciating technical course subjects, the value of add-on or refresher instruction, and variable risk experiences are noted in explaining differences in some training results.

Analysis of Variance↗

PubMed2003

Executive cognitive deficits in primary dystonia.

Primary dystonia is a disorder of movement for which no consistent pathophysiology has been identified; in the absence of evidence to the contrary, it is assumed to be cognitively benign. We have studied a clinically heterogeneous group of 14 patients with primary dystonia on a battery of neuropsychological tests. Despite well-preserved speed of information processing, language, spatial, memory and general intellectual skills relative to normal controls, we have identified a constellation of attentional-executive cognitive deficits on the Cambridge Neuropsychological Test Automated Battery (CANTAB). Specifically, patients demonstrated significant difficulties negotiating the extra-dimensional set-shifting phase of the IED task. The implications of these findings for the pathophysiology of primary dystonia are discussed. This is, to the best of our knowledge, the first report of a significant cognitive deficit in patients with primary dystonia.

Adult↗

PubMed2001

Attentional bias associated with alcohol cues: differences between heavy and occasional social drinkers.

RATIONALE: Previous research has shown an attentional bias toward drug-related stimuli in opiate addicts and toward emotionally threatening words in anxiety patients. OBJECTIVE: The primary aim of this study was to investigate whether non-dependent heavy social drinkers would differ in their selective attention towards alcohol-related stimuli in comparison with a group of occasional social drinkers. METHODS: Attentional bias was assessed using alcohol-related pictures and words in a dot probe detection task. Picture and word pairs were visually presented, followed by a dot probe that replaced one of the items. Attentional bias was determined from latencies in responding to the dot probe. Questionnaires were used to examine the relationships among attention, outcome expectancies after alcohol consumption, and personality traits. Higher-order executive function was also measured with two cognitive tasks, recognition memory and attentional shift. RESULTS: The heavy social drinkers showed an attentional bias towards the alcohol-related stimuli when compared to the occasional social drinkers. The heavy social drinkers also scored more highly on expectancy factors of sociability and sexuality and lower on the personality traits of self-directedness and persistence. CONCLUSION: The results support cognitive theories of addictive behaviour in which the ability of drug-related stimuli to capture attention is suggested to play a part in drug dependence, craving and relapse.

Adolescent↗

PubMed1989

A developmental study of covert orienting to peripheral visual cues.

Observers aged 6, 8, and 20 years participated in a speeded classification task designed to measure covert shifts of visual attention. On each trial observers responded to a target which appeared in one of three locations arrayed horizontally across the display. Three prestimulus cues were employed: neutral (the cue was present in all three possible target locations), unpredictable (the cue was present in the target location on a random basis), and predictable (the cue was present in the target location on 80% of the trials). There were four developmental findings: (1) Observers of all ages oriented attention automatically to the cued locations, (2) children processed targets in non-cued locations more slowly than adults, (3) only adults took advantage of the predictability of the cue, and (4) all age groups provided evidence that strategic orienting competes with response priming for cognitive resources. The implications of these findings for theories of attentional development are discussed.

Adult↗

PubMed1983

Evoked potential indices of selective hemispheric engagement in affective and phonetic tasks.

Evoked potentials (EPs) to a probe click stimulus were recorded from left and right temporal areas of dextral adults engaged in phonetic and prosodic processing of an emotionally charged tape recorded conversation. Attenuation of the probe EP amplitudes was significantly greater in the left and right hemispheres during the phonetic and prosodic tasks, respectively, indicating lateral dominance shifts depending on selective processing of linguistic vs affective cues conveyed by the same speech signals.

Adult↗

PubMed1996

Long-term effects of antidepressants on balance, equilibrium, and postural reflexes.

To assess the long-term effects of antidepressant medication on balance, equilibrium, and postural reflexes, we studied 30 patients, ages 20-76 years, who had a diagnosis of depressive disorder (as defined by DSM-III-R criteria) and had been treated with tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) for > or = 1 year. They were assessed by a Balance Master System. The assessment included three tasks: static balance, rhythmic weight shift, and limits of stability. When compared with 30 nonhospitalized healthy controls (of comparable age and the same sex), patients who took TCAs showed impaired balance function in all main indices. The results suggest that the impairment of balance function includes motor coordination, fine-motor control, postural reflexes, maintaining equilibrium, and reaction time. No obvious impairment of balance function was observed in patients who took SSRIs.

Adult↗

PubMed2004

Fluoxetine facilitates use-dependent excitability of human primary motor cortex.

OBJECTIVES: In poststroke patients, fluoxetine, a selective serotonin-reuptake inhibitor, as an adjunct to physical therapy provided a better functional recovery from motor deficits. The aim of this study was to investigate the effect of a single dose of 20 mg fluoxetine on motor learning and associated cortical changes in healthy right-handed subjects in order to get deeper insight into its facilitating influence on human motor cortex. METHODS: Subjects performed a motor task consisting of a simultaneous co-contraction of the abductor pollicis brevis (APB) and the deltoid muscle with and without fluoxetine in a placebo-controlled double-blinded crossover study design. Immediately before and after motor learning motor output maps of the APB muscle were assessed in order to get insight into plastic changes of the muscle representation. RESULTS: We found a significantly improved motor performance under both conditions without having substantial differences between placebo and fluoxetine. After the completion of the motor task there was a medial shift of the APB muscle motor output map. Only after the administration of fluoxetine the sum of MEP amplitudes (SOA) increased and the motor output map enlarged. CONCLUSIONS: These findings provide evidence for a use-dependent facilitating effect of fluoxetine on cortical excitability but not on motor performance. SIGNIFICANCE: Our findings are not in line with previous experiments in poststroke patients. However, long-term treatment with fluoxetine may additionally improve motor function by upregulating serotonergic receptors. Further studies investigating the influence of long-term treatment on cortical excitability and psychophysics may therefore provide deeper insight into a possible therapeutical efficiency of fluoxetine in poststroke patients.

Adult↗

PubMed2006

Attention-deficit hyperactivity disorder involves differential cortical processing in a visual spatial attention paradigm.

OBJECTIVE: Inattention is undoubtedly one of the main characteristics of Attention-deficit hyperactivity disorder (ADHD). Nevertheless, a growing corpus of evidence shows that not all attentional processes are affected in this condition. This study aimed to explore the distribution of attentional resources in children with ADHD via a spatially shifted double-oddball visual task. METHODS: We recorded event-related potentials (ERPs) for all visual stimuli. Subjects were instructed to allocate attention in a specific area of visual space while ignoring all stimuli presented outside. Ten male children (age: 9-14; mean = 11.6 +/- 2.1) who met DSM-IV criteria for the ADHD combined subtype participated in the study, along with ten age- and sex-matched healthy controls (9-14; mean = 11.2 +/- 2.3). RESULTS: ADHD subjects showed late differential cortical responses to initially suppressed irrelevant stimuli. The amplitude of early N1-P1 components were mainly modulated by stimulus location and showed no significant differences between groups, but a late P300-like positivity was clearly evoked in the ADHD group by peripheral stimuli. CONCLUSIONS: These results suggest that ADHD may not compromise the early attentional spatial filter but rather entails a different distribution of attentional resources at later stages of cortical processing. Perhaps these differences may be attributable to individual differences in attentional mechanisms. SIGNIFICANCE: ADHD may not affect initial focusing of visual attention but rather the allocation of processing resources in later stages.

Adolescent↗