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PubMed2004

Worker performance and ventilation in a call center: analyses of work performance data for registered nurses.

UNLABELLED: We investigated the relationship between ventilation rates and individual work performance in a call center, and controlled for other factors of the indoor environment. We randomized the position of the outdoor air control dampers, and measured ventilation rate, differential (indoor minus outdoor) carbon dioxide (DeltaCO(2)) concentration, supply air velocity, temperature, humidity, occupant density, degree of under-staffing, shift length, time of day, and time required to complete two different work performance tasks (talking with clients and post-talk wrap-up to process information). DeltaCO(2) concentrations ranged from 13 to 611 p.p.m. We used multivariable regression to model the association between the predictors and the responses. We found that agents performed talk tasks fastest when the ventilation rate was highest, but that the relationship between talk performance and ventilation was not strong or monotonic. We did not find a statistically significant association between wrap-up performance and ventilation rate. Agents were slower at the wrap-up task when the temperature was high (> 25.4 degrees C). Agents were slower at wrap-up during long shifts and when the call center was under-staffed. PRACTICAL IMPLICATIONS: The productivity benefits of ventilation rates that exceed common standards such as ASHRAE Standard 62 may be small (0-2%), and other factors may have a larger impact on productivity. Understaffing and long shifts should be avoided because both showed a negative impact on performance. In this study, high temperature had the largest statistically significant impact on productivity and was caused by occupants fighting over the thermostat setpoint. Care should be taken to avoid high temperatures in call centers. If occupants are allowed to adjust temperature setpoints, then the size and/or duration of the setpoint change should be restricted.

Humans↗

PubMed2006

New Zealand's Christchurch Hospital at night: an audit of medical activity from 2230 to 0800 hours.

OBJECTIVE: To audit medical activity at Christchurch Hospital New Zealand between 2230 and 0800 hours; specifically, to measure the volumes of tasks requiring completion overnight and to identify the competencies required for this as well as the level of teamwork that existed. DESIGN: After a pilot study tested possible methods, Resident Medical Officers (RMOs) responsible for the care of adult patients at night were linked by a shift coordinator to recorders (mostly nursing students) trained to register the tasks performed, together with task urgency (as judged by the RMO) and duration. This information, checked each morning for completeness, was entered immediately into a database and analysed later. Telephonists logged all outbound calls through the hospital switchboard to on-call medical staff; theatre and admission records were recorded as usual. Anaesthetic and Radiology Registrar activity was self-recorded. SETTING: Christchurch Hospital is a 650 bed tertiary centre, which covers most specialties. MAIN OUTCOMES: In the absence of leadership, the RMOs were not working as a team. Consequently some were overextended while others were inactive. House officer tasks were largely generic--not specialty specific; there was no formal handover from the afternoon or day shifts and the level of hospital medical staffing did not reflect the activity levels over the time period studied. A review of the beep policy is urgently needed. A third of the admissions were to General Medicine, and basic medical activities (including admitting, reviewing, and prescribing drugs and fluids) for patients admitted under all specialties represented the majority of the night workload. Medical registrars had reduced some of the traditional multiple clerking by admitting patients themselves. The workload and its distribution over time was remarkably similar to that found at the 17 pilot sites in the United Kingdom, where Out of Hours Multidisciplinary Teams (OoHMT) were introduced. CONCLUSION: We recommend that Christchurch Hospital use these data to plan the composition and leadership of an OoHMT.

Hospitals, Public↗

PubMedDate not supplied

Eye movement task related to frontal lobe functioning in children with attention deficit disorder.

OBJECTIVE: Attention-deficit hyperactivity disorder (ADHD) has been postulated to be related to dysfunction of the prefrontal cortex. In the oculomotor delayed response task, a subject is cued as to where he or she should look (shift visual gaze to) but must delay a short period and then shift gaze to the location where the cue previously existed but no longer exists (a memory-guided saccade). Dependent measures from this task provide information on three functions tentatively tied to prefrontal cortex functioning: the ability to inhibit response (during the delay period), preparation of motor response (inversely tied to the latency of shifting visual gaze), and accuracy of working visuospatial memory (accuracy of the memory-guided saccade). METHOD: Thirteen children with ADHD and 10 normal controls, aged 9 to 12 years, were tested using an 800-msec delay period. RESULTS: Children with ADHD showed, relative to normal controls, deficits on inhibiting response during the delay period but no differences in latency (preparation of motor response) or accuracy of visuospatial memory. CONCLUSIONS: These results support the hypothesis that the primary deficit in ADHD is difficulty in inhibition of response. This deficit may be associated with pathology located outside the dorsolateral prefrontal cortex.

Adolescent↗

PubMed1993

Shifts of visual attention at fixation and away from fixation.

Attention shifts in the visual field were investigated using a task in which two numerals were flashed one by one, the duration of each numeral being 33 msec. Both numerals were followed by a mask pattern (100 msec in duration). The observer was asked to report the two numerals. If the observer correctly recognized both numerals, it implies that he was able to perform a simple act of attention shift from one item to the next. In the foveal experiment, both numerals were presented at fixation--the second numeral on top of the first. In the extrafoveal experiment, the numerals were also flashed sequentially but in different locations: the first numeral was at fixation and the second at 7 deg eccentricity. The results showed that the observers could not shift attention away from fixation to an extrafoveal position as efficiently as they could maintain attention at fixation.

Attention↗

PubMed2005

Involvement of both prefrontal and inferior parietal cortex in dual-task performance.

This PET study explored the neural substrate of both dual-task management and integration task using single tasks that are known not to evoke any prefrontal activation. The paradigm included two simple (visual and auditory) discrimination tasks, a dual task and an integration task (requiring simultaneous visual and auditory discrimination), and baseline tasks (passive viewing and hearing). Data were analyzed using SPM99. As predicted, the comparison of each single task to the baseline task showed no activity in prefrontal areas. The comparison of the dual task to the single tasks demonstrated left-sided foci of activity in the frontal gyrus (BA 9/46, BA 10/47 and BA 6), inferior parietal gyrus (BA 40), and cerebellum. By reference to previous neuroimaging studies, BA 9/46 was associated with the coordinated manipulation of simultaneously presented information, BA 10/47 with selection processes, BA 6 with articulatory rehearsal, and BA 40 with attentional shifting. Globally similar regions were found for the integration task, except that the inferior parietal gyrus was not recruited. These results confirm the hypothesis that the left prefrontal cortex is implicated in dual-task performance. Moreover, the involvement of a parietal area in the dual task is in keeping with the hypothesis that a parieto-frontal network sustains executive functioning.

Acoustic Stimulation↗

PubMed2006

Theory of mind and the right cerebral hemisphere: refining the scope of impairment.

The neuropsychological and functional characterisation of mental state attribution ("theory of mind" (ToM)) has been the focus of several recent studies. The literature contains opposing views on the functional specificity of ToM and on the neuroanatomical structures most relevant to ToM. Studies with brain-lesioned patients have consistently found ToM deficits associated with unilateral right hemisphere damage (RHD). Also, functional imaging performed with non-brain-injured adults implicates several specific neural regions, many of which are located in the right hemisphere. The present study examined the separation of ToM impairment from other deficits associated with brain injury. We tested 11 patients with unilateral right hemisphere damage (RHD) and 20 normal controls (NC) on a humour rating task, an emotion rating task, a graded (first-order, second-order) ToM task with non-mentalistic control questions, and two ancillary measures: (1) Trails A and B, in order to assess overall level of impairment and set-shifting abilities associated with executive function, and (2) a homograph reading task to assess central coherence skills. Our findings indicate that RHD can result in a functionally specific deficit in attributing intentional states, particularly those involving second-order attributions. Performance on ToM questions was not reliably related to measures of cognitive impairment; however, performance on non-ToM control questions was reliably predicted by Trails A and B. We also discuss individual RHD patients' performance with attention to lesion locus. Our findings suggest that damage to the areas noted as specialised in neuroimaging studies may not affect ToM performance, and underscore the necessity of combining lesion and imaging studies in determining functional-anatomical relations.

Adult↗

PubMed1976

Effects of industrialization on working schedules.

Recent increase in industrialization has resulted in attention being drawn to diversity of working schedules and their interrelation with content of work. The results of joint research revealed that adaptation to industrial jobs is made difficult because of urban conditions and modern work-control systems, such as workers in flexible-working-time systems who apparently favored regular daily working cycles. Long overtime work in smaller undertakings and the spread of shift systems are two important features of industrial work schedules, each being dominant among skilled and non-skilled jobs. Another important facet is the problem of intra-shift work-rest schedules significant for machine operations and vigilance tasks. It is suggested that phases of work that become intolerable are correlated with unnatural work rhythms. More emphasis should thus be laid on both phase-shifted work and non-self-governing work, the key factor being the relevance of attained data to real work in the whole course of schedules of work and rest.

Accidents, Occupational↗

PubMedDate not supplied

Ethanol-induced alterations in EEG alpha activity and apparent source of the auditory P300 evoked response potential.

The relationship among topographic brain electrical activity mapping, auditory-evoked response potentials (ERPs), plasma ethanol levels and subjective reports of intoxication was examined in 4 male volunteers. The source of the auditory P300 ERP (a measure of selective attention and memory encoding) was estimated using a recently developed computer program. The effect of ethanol on the P300 wave was studied using a standard oddball paradigm both with and without a concomitant divided attention task. Ethanol (0.7 g/kg) administration produced marked increases in EEG alpha activity during the ascending limb of the blood ethanol curve. Acute ethanol administration caused a delay in the latency and a reduction in the amplitude of the auditory P300 ERP. A similar effect on P300 topography was noted in waves that were affected by the tones while the subjects also listened to a story (divided attention). After ethanol, the source of the P300 wave appeared to have shifted to a position posterior and inferior to its original location. P300 ERP's generated during the divided attention task were also disrupted and shifted to positions inferior to their original. However, the variability of the dipole vector was much greater during the divided attention task than after ethanol administration. These data demonstrate that ethanol's effects on cognitive processing skills may be similar to those produced when individuals experience distractions while concentrating on a task.

Adult↗

PubMed1995

The locus of the lexical shift in phoneme identification.

The lexical identification shift is used as a measure of speech processing in the phoneme identification task (W. F. Ganong, 1980). Interactive (bottom-up and top-down) models of word recognition account for the shift by claiming that lexical knowledge feeds back to a prelexical level and aids speech processing. Autonomous models (bottom-up only) maintain that the shift arises by other means and at later stages of processing. The locus of the lexical shift was investigated by using detection theory analysis procedures to measure perceptual changes in phoneme processing. Lexical status (word-nonword) of the utterance was varied in Experiments 1 and 3 and was found to influence phoneme processing. In Experiment 2 the effects of a postperceptual manipulation, monetary payoff, did not show up in the detection theory analysis. Implications of the results for both classes of models are discussed.

Humans↗

PubMed1981

Effects of frequency-shifted feedback on the pitch of vocal productions.

Previous investigations into the effects of distorted auditory feedback on vocalizations have been limited to manipulations of intensity, background noise, temporal delay, or to selective filtering of frequency. The current study reports the results of real-time shifts of the frequency components of auditory feedback. Subjectively, such shifts are perceived primarily as an alteration in the fundamental frequency (F0) of the speech. Subjects performed a variety of tasks under conditions where they received either normal auditory feedback or frequency-shifted feedback. Under normal feedback conditions, subjects maintained approximately constant F0 as instructed. With frequency-shifted feedback, subjects attempted to compensate for the shift by adjusting their F0 up or down such that the resulting feedback appeared to be "normal."

Feedback↗

PubMed1998

Three-process model of supervisory activity over 24 hours.

OBJECTIVES: This study used endogenous and exogenous factors to develop a model for sampling supervisory activity that implied consulting numerous data on computer systems. METHODS: The study was carried out in an automated workshop of a chemical plant. Five crews worked on a 3x8 hour shift system, with changes at 0400, 1200 and 2000. Each team included 2 experienced controllers who supervised the process from computer systems in a control room. Starting and ending duty at the same time as the operators, the researchers used real time to code of all the screen pages selected on the computers by 8 controllers (from 4 teams) over 18 shifts. RESULTS: The time-of-day fluctuations of the call frequency confirmed the existence of endogenous factors (biological rhythms or fatigue), but they cannot explain all the variations observed. The modeling of the data yielded the following 3 explanatory factors: (i) the cognitive demands of the tasks, as an external factor, mainly concern the impact of shift changeover characterized by a strong peak of information gathering at the beginning of the shift, even at 0400; (ii) the shift duration appears as a "fatigue" factor and reflects a rapid reduction of information gathering over the shift; (iii) circadian rhythms are characterized by a minimum of activity at night and a maximum in the afternoon. CONCLUSION: In other similar work situations, in addition to an essential work analysis, our model could help the design of shift duration or schedules for shift changeover.

Adult↗

PubMed2005

Frontostriatal microstructure modulates efficient recruitment of cognitive control.

Many studies have linked activity in a frontostriatal network with the capacity to suppress inappropriate thoughts and actions, but relatively few have examined the role of connectivity between these structures. Here, we use diffusion tensor imaging to assess frontostriatal connectivity in 21 subjects (ages 7-31 years). Fifteen subjects were tested on a go/no-go task, where they responded with a button press to a visual stimulus and inhibited a response to a second infrequent stimulus. An automated fiber tracking algorithm was used to delineate white matter fibers adjacent to ventral prefrontal cortex and the striatum, and the corticospinal tract, which was not expected to contribute to control per se. Diffusion in frontostriatal and corticospinal tracts became more restricted with age. This shift was paralleled by an increase in efficiency of task performance. Frontostriatal radial diffusivities predicted faster reaction times, independent of age and accuracy, and this correlation grew stronger for trials expected to require greater control. This was not observed in the corticospinal tract. On trials matched for speed of task performance, adults were significantly more accurate, and accuracies were correlated with frontostriatal, but not corticospinal, diffusivities. These findings suggest that frontostriatal connectivity may contribute to developmental and individual differences in the efficient recruitment of cognitive control.

Adolescent↗

PubMedDate not supplied

Shape and the first hundred nouns.

This paper reports evidence from a longitudinal study in which children's attention to shape in a laboratory task of artificial noun learning was correlated with a rate shift in noun acquisitions. Eight children were tested in the laboratory at 3-week intervals beginning when they had less than 25 nouns in their productive vocabulary (M age=17 months). Children were presented with a novel word generalization task at each session. Additionally, the study examined the kinds of words the children learned early, based on parent reports, and the statistical regularities inherent in those vocabularies. The results indicate that as children learned nouns, they also learned to attend to shape in the novel word task. At the same time, children showed an acceleration in new noun production outside of the laboratory.

Attention↗

PubMed1990

Shift toward left visual field advantage after short-term learning experience.

The purpose of the present study was to examine the effect of the short-term learning experience on visual field difference. Firstly, the random shape was briefly presented in a left or right visual field (Test 1), then the paired-associated learning task associated with the stimulus shape was carried out. Several days later the same laterality task was conducted again (Test 2). The results showed a shift toward left visual field advantage (LVF-A) between Tests in the relevant label learning group, a trivial shift toward RVF-A in the irrelevant/concrete label learning group, a shift toward RVF-A in the irrelevant/abstract label learning group, and no shift in no-learning group. The relationship between the direction of the shifts of cerebral hemispheric asymmetry and label types was discussed.

Adult↗

PubMed1994

Current models of death, dying, and bereavement.

This article reviews recent task-based models in the field of death, dying, and bereavement. An argument is made for the importance of theoretical models that emphasize individual tasks in coping with dying and bereavement. Such models seek to shift perspective from passive victimization to an opportunity for active processes, whereby one can regain some measure of control and meaning in living with loss. The appropriateness of task-based models for nurses in general and for critical care nurses in particular is suggested.

Adaptation, Psychological↗

PubMed1996

Cognitive deficits in Machado-Joseph disease.

Cognitive function was examined in 6 patients with genetically confirmed Machado-Joseph disease (MJD) and 15 age- and ethnically matched controls using a series of subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB), a touch screen-based testing system previously validated in a number of movement and neurodegenerative disorders. The MJD patients had deficits in visual attentional function that were characterized by a slowing of the processing of visual information when task demands were high and an inability to shift attention to previously irrelevant stimulus dimensions to discriminate between complex stimuli. Tests of learning and visual memory were normal. These results demonstrate that specific cognitive deficits occur in patients with MJD, independent of motor dysfunction, and these deficits may reflect disruption to frontosubcortical pathways.

Adult↗

PubMed2001

Does aging affect the allocation of visual attention in global and local information processing?

The earliest studies of Navon (1977) showed that in certain conditions the visual perception of hierarchical stimuli generates a global precedence effect. This hypothesis is based on the joint occurrence of two effects: a response time (RT) advantage for identifying global targets and interference by global distractors when responding to a local target. The aim of the present study was to determine the involvement of attentional mechanisms and whether certain aspects are specifically altered by normal aging. In a selective-attention task, a complete global precedence effect was found for young and old subjects. However, for the old subjects, global interference on local identification was more pronounced than for the young subjects. In a divided-attention task, the RT advantage was affected by attention shifts between global and local forms for both young and old subjects, but the global interference effect did not change.

Adult↗

PubMed1989

Relations between covert orienting and filtering in the development of visual attention.

This study examined a widely held assumption concerning the development of visual attention, namely, that different aspects of visual selectivity depend on common processing resources. Observers aged 5, 7, 9, and 24 years participated in a speeded classification task designed to examine the relations between covert shifts of attention and filtering. There were three important findings: (1) covert orienting and filtering share processing resources, (2) the ability to orient covertly to a target location and to filter competing information on the same trial became more efficient with age, and (3) 5 year olds were able to filter as efficiently as adults when target location was precued. The implications of these results for theories of attentional development are discussed.

Adult↗