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PubMed1991

Nurse burnout: work related and demographic factors as culprits.

This study was an examination of the combined ability of perceived work environment, demographic, and work-related variables to predict burnout among 314 nurses at a large metropolitan hospital. The three dimensions of burnout measured were emotional exhaustion, depersonalization, and personal accomplishment. High work pressure and low work involvement and supervisor support predicted emotional exhaustion. Task orientation, work pressure, work involvement, and age predicted both depersonalization and personal accomplishment. Burnout among nurses on each of the three work shifts also was examined. Results are discussed from the perspective of how to decrease or to prevent burnout among nurses.

Adult↗

PubMed1989

Left and right-handed dyslexic boys: an empirical test of some assumptions of the Geschwind-Behan hypothesis.

Twenty-six dyslexic boys (13 left-handers and 13 right-handers) were tested for hemispheric asymmetry with dichotic listening (DL) and a visual half-field test (VHF). The purpose of the study was an empirical test of the Geschwind-Behan [Proc. natn. Acad. Sci. USA 79, 5097-5100, 1982] hypothesis of a difference in hemispheric asymmetry between left- and right-handed dyslexic boys. Following Geschwind and Behan, left-handedness and dyslexia are caused by a common factor affecting the development of the left hemisphere in utero which results in a right hemisphere dominance. As a consequence, handedness but not language is shifted to the right hemisphere. We therefore predicted that left-handed dyslexics should be superior to right-handed dyslexics on visuospatial tasks, but perform similar to right-handers on verbal tasks. The results revealed a significant right ear advantage (REA) in both groups during a dichotic listening test to verbal stimuli. The left-handed group was however superior to the right-handed group in recognition of visuo-spatial stimuli presented in the left half-field in a visual half-field test. It is concluded that the results provide some, although weak, support for the Geschwind-Behan hypothesis.

Adolescent↗

PubMedDate not supplied

Differential effects of DGAVP on acquisition and extinction of active avoidance behavior.

DGAVP facilitates consolidation and retrieval of active and passive avoidance behavior. In this study it was tested whether the long-term behavioral effects of DGAVP are the consequence of an initial increase in behavioral arousal during the learning phase. Animals that were preestimated in an open field test to be low active showed a lower number of conditioned avoidance responses (CAR's) during acquisition and extinction of a shuttle-box task than high active rats. DGAVP was administered 40 min prior to the 1st acquisition session. The immediate effect of DGAVP was a shift in the bell-shaped curve of the relation between arousal and performance (13); an increase in acquisition performance was observed with a low dose of DGAVP (0.1 microgram), while a decrease was found with a high dose of DGAVP (1 microgram). A dose-dependent inhibition of extinction was found in both low and high active animals. These results suggest an immediate effect of DGAVP on the rate of acquisition behavior, which may be a direct consequence of its arousing properties, and a long-term effect on extinction, indicating the formation of memory traces specific for vasopressin-related neuropeptides.

Animals↗

PubMed1989

Frontal lobe dysfunction and memory impairment in patients with chronic progressive multiple sclerosis.

Deficits in semantic encoding have been described in patients with frontal lobe disease who also show memory impairments. As a group, patients with multiple sclerosis (MS) exhibit memory impairment, fail to make effective use of semantic encoding to aid memory, and perform poorly on verbal fluency and concept formation tests which are sensitive to frontal lobe damage. In the present study the semantic encoding capacity of MS patients was measured using a modification of Wicken's release from proactive interference (PI) paradigm. Individual patients varied considerably in the severity of their impairments on verbal fluency, verbal recognition memory and on Wisconsin Card Sorting Task, but even patients who evidenced both memory impairment and signs of frontal lobe dysfunction showed normal release from PI after a categorical shift. Memory disturbances in MS are unlikely to result from an incapacity for semantic encoding, which seems preserved in MS, but may arise instead from deficits in processing information rapidly.

Adult↗

PubMed2005

Neural evidence of effects of emotional valence on word recognition.

There are no clear reports of electrophysiological evidence of the facilitating effect of negative valence on word recognition. However, behavioral psychological studies have suggested that negative words can be recognized more accurately than positive and neutral words. This study aimed to examine whether, and if so how, the valence of words could influence accuracy and event-related potentials (ERPs) in a recognition task. ERPs were recorded from 20 healthy subjects during performance of a word recognition task. We found a behavioral advantage in discriminability between old and new items for negative words. As for ERPs, the positive-going shift was evident for correct responses to targets in late latency at midline and left centro-parietal sites. Additionally, the magnitude of this component was greatest for negative targets, next for positive targets, and least for neutral targets. The findings offer support for the idea that negative content greatly accelerates recognition memory compared to positive and neutral words.

Adolescent↗

PubMed1997

Time to detect the difference between two images presented side by side.

The time to locate a difference between two artificial images presented side by side on a CRT screen was studied as a function of their complexity. The images were square lattices of black or white squares or quadrangles, in some cases delineated by a blue grid. Each pair differed at a single position, chosen at random. For images of size N x N, the median reaction time varied as cN2, from N = 3-15, with c being around 50 ms in the absence of grid (i.e., when the quadrangles were associated into continuous shapes). For N < or = 9, when the lattice was made irregular, performance did not deteriorate, up to a rather high level of irregularity. Furthermore, the presence of uncorrelated distortions in the left and right images did not affect performance for N < or = 6. In the presence of a grid, the reaction times were on average higher by 20%. The results taken together indicate that the detection of differences does not proceed on a point-by-point basis and must be mediated by some abstract shape analysis, in agreement with current views on short-term visual memory (e.g., Phillips, W.A., On the distinction between sensory storage and short-term visual memory, Percept. Psychophys., 16 (1974) 283-290 [13]). In complementary experiments, the subjects had to judge whether two images presented side by side were the same or different, with N varying from 1 to 5. For N < 3, the same and the different responses were similar in all their statistical aspects. For N > or = 4, the "same" responses took a significantly larger time than the "different" responses and were accompanied by a significant increase in errors. The qualitative change from N = 3 to N = 4 is interpreted as a shift from a "single inspection" analysis to an obligatory scanning procedure. On the whole, we suggest that visual information in our simultaneous comparison task is extracted by chunks of about 12 +/- 3 bits, and that the visual processing and matching tasks take about 50 ms per couple of quadrangles. In Section 4, we compare these values to the values obtained through other experimental paradigms.

Humans↗

PubMed2003

From will to action: sequential cerebellar contributions to voluntary movement.

The cerebellum is known to be involved in numerous motor related functions, but recent observations suggest that it also performs fundamental operations on nonmotor functions such as perception and cognition. Assuming that the cerebellum has to be consulted in a limited window of time, cerebellar activation should occur in a time-dependent manner in respect to the corresponding telencephalic areas. This hypothesis was tested by combining a simple motor task with the demand of a self-paced delay using event-related functional magnetic resonance imaging. Evaluation with a time-shifted canonical hemodynamic response function revealed spatially and temporally separated cerebral and cerebellar activation accompanying the entire process--from conscious planning to final motor output--within a time frame of 6 s. The cerebral activations spread from the anterior cingulate cortex through the supplementary motor and premotor area to the primary motor and sensory cortices. This cascade was temporally in parallel with cerebellar activations propagating from the neo- to the spinocerebellum. An early lateral cerebellar recruitment 3 s prior movement onset confirms its involvement in cognitive processing. A later medial activation occurring close to movement onset most probably reflects spinocerebellar kinesthetic feedback. Between these two points a striking lateromedial succession was found, which is in line with the hypothesis of the existence of multiple internal models residing in the cerebellum, each communicating with its own corresponding telencephalic region.

Adult↗

PubMedDate not supplied

Decontamination of mass casualties--re-evaluating existing dogma.

The events of 11 September 2001 became the catalyst for many to shift their disaster preparedness efforts towards mass-casualty incidents. Emergency responders, healthcare workers, emergency managers, and public health officials worldwide are being tasked to improve their readiness by acquiring equipment, providing training and implementing policy, especially in the area of mass-casualty decontamination. Accomplishing each of these tasks requires good information, which is lacking. Management of the incident scene and the approach to victim care varies throughout the world and is based more on dogma than scientific data. In order to plan effectively for and to manage a chemical, mass-casualty event, we must critically assess the criteria upon which we base our response. This paper reviews current standards surrounding the response to a release of hazardous materials that results in massive numbers of exposed human survivors. In addition, a significant effort is made to prepare an international perspective on this response. Preparations for the 24-hour threat of exposure of a community to hazardous material are a community responsibility for first-responders and the hospital. Preparations for a mass-casualty event related to a terrorist attack are a governmental responsibility. Reshaping response protocols and decontamination needs on the differences between vapor and liquid chemical threats can enable local responders to effectively manage a chemical attack resulting in mass casualties. Ensuring that hospitals have adequate resources and training to mount an effective decontamination response in a rapid manner is essential.

Decontamination↗

PubMed1996

Sudden insight: all-or-none processing revealed by speed-accuracy decomposition.

Issues surrounding the discreteness or continuity of cognitive processes have played a major role in experimental psychology, although there has been relatively little work that directly addresses these topics. Nevertheless, there has been a shift away from discrete models and toward continuous ones. The research reported in this article demonstrates discrete processing of information in an anagram task selected because of its similarity to insight problems, which seem subjectively to produce discrete "illumination" during processing. The authors used speed-accuracy decomposition (SAD), a relatively new technique for investigating the time course of information processing. The results of 2 experiments indicate little or no partial information in the anagram tasks, in contrast to previous research with SAD, all of which has revealed partial information. General models of human information processing must therefore be able to account for both patterns.

Cognition↗

PubMed2002

Visual discrimination learning and strategy behavior in the fat-tailed dunnart (Sminthopsis crassicaudata).

Fat-tailed dunnarts (Sminthopsis crassicaudata) were trained on visual discrimination learning-set, reversal-set, and spatial delayed-alternation tasks. The learning set involved 36 2-way black-and-white pattern discriminations and 5 probe reversals. Ten reversals of a black-and-white pattern discrimination were followed by 5 novel tasks. Spatial alternation was tested at delays up to 20 s. Learning-set and reversal-set formation, including 1-trial learning and spontaneous transfer from learning set to reversals and vice versa, was found. Learning-set-experienced dunnarts showed no retention of previously learned tasks 1 week after testing but demonstrated consistently high Trial 2 performance, indicating the retention of a response strategy. Delayed-alternation tasks were learned up to 10-s delays. These results provide the first evidence of a visually guided "win-stay, lose-shift" strategy in a marsupial.

Analysis of Variance↗

PubMed1997

The nature of word-finding errors of preschoolers with and without word-finding deficits.

Twelve preschoolers with word-finding deficits (WF) and their age-matched normally developing (ND) peers participated in three tasks requiring word finding: the noun-naming and verb-naming subtests of the Test of Word Finding (TWF-N, TWF-V) and story retelling. The general error profiles of the two subject groups were similar. Semantic errors were always more common than phonological errors and were typically more common than unrelated errors (e.g., "I don't know" responses). The difference in proportions of semantic and phonological substitutions constitutes developmental evidence for lemma and lexeme distinctions as proposed in adult-based models of lexical storage. Furthermore, the predominance of errors that bore semantic relations to their targets produced by both ND and WF groups suggests an early and robust organization of lexical storage into a network of related information. Despite similarities between the two subject groups, the word-finding deficits of the WF group were manifested in two ways. First, compared to the ND group, the WF group demonstrated significantly higher rates of naming errors on all three tasks; second, they demonstrated significantly different proportions of error types on two of the three tasks. Specifically, the WF group produced a lower proportion of related errors on the TWF-V and a lower proportion of semantic errors on the story-retell task. One clinical implication of these findings concerns measurement of treatment outcomes. A reduction in the number of errors as well as a shift in the error profile towards higher proportions of related errors, especially semantic errors, may indicate progress in word-finding development.

Child Language↗

PubMed2006

Do visual attentional factors contribute to phonological ability? studies in adult dyslexia.

A case study approach was taken to examine the role of visual attention and auditory memory processes in eight adults with dyslexia, all of whom demonstrated phonological difficulties. The participants were administered a battery of neuropsychological tests and participated in an attentional cueing experiment. Individual data revealed that, although one adult with dyslexia showed overt visual attention deficits on a visual search task, and five showed auditory working memory deficits, the difficulty that all of the adults with dyslexia had in common was with covert shifts of attention toward and away from fixation. These results indicate that deficits in overt visual attentional processing and working memory can be present with dyslexia, but neither is a necessary requirement. Overall, the results suggest that covert visual attention makes a significant contribution to phonological ability, which thus has implications for reading ability.

Acoustic Stimulation↗

PubMed1984

Forced activity alters sleep cycle periodicity and dorsal raphe discharge rhythm.

Single-cell activity recorded from the brain stem dorsal raphe nucleus (DRN) of cats showed a regular firing pattern during wakefulness (2-3 spikes/s), decreased activity during slow-wave or synchronized sleep (1 spike/s), and cessation of regular discharge during desynchronized sleep (0.05 spikes/s). DRN discharge was negatively correlated with the onset and maintenance of the polycyclic desynchronized sleep rhythm. These findings were derived from analyses of DRN firing rate sampled during different behavioral states. The present time-course analyses of DRN discharge described for the first time the period, amplitude, and phase characteristics of DRN activity relative to the timing of behavioral states that comprise the complete sleep cycle. The time course of both DRN discharge and the occurrence of wakefulness, slow-wave (S) sleep, transition, and desynchronized (D) sleep were behaviorally manipulated. Forced locomotor activity imposed by a treadmill task shortened the period length of the sleep cycle and the duration of the DRN discharge cycle. The magnitude and direction of these shifts in period length were consistent across multiple sleep cycles, and there was a high degree of coherence between the period length of the sleep cycle and the DRN discharge profiles. The DRN discharge rate also displayed phase dependence within S and D sleep. These results support the hypothesis that the DRN has a physiological role in regulating the timing of the ultradian sleep cycle.

Animals↗

PubMed1992

Planning mental health services: I. Background and key issues.

Planning mental health services is a complex task requiring an understanding of background developments and key issues related to mental health services. In Canada, the deinstitutionalization of patients attempted to shift the locus of care from provincial psychiatric hospitals to general hospital psychiatric units. This resulted in the isolation of provincial psychiatric hospitals, general hospital psychiatric units and community mental health programs, with little overall accountability for the services provided--three solitudes. To move toward the creation of responsible, integrated systems a number of issues must be addressed: target population(s); the roles of provincial psychiatric and general hospitals; community support services; continuity of care; co-morbidity; consumerism; and methods of integration. In the development of a comprehensive mental health plan, each issue should be recognized and decisions made which are in keeping with current knowledge. A companion report will survey Canadian initiatives in mental health planning and discuss approaches to many of the issues identified.

Activities of Daily Living↗

PubMed1996

Rehabilitation of frontal/executive impairments in schizophrenia.

OBJECTIVE: A relatively high prevalence of deficits in cognitive flexibility, working memory and planning ability has been reported in schizophrenia patients. The objective was to develop a rehabilitation training program in an attempt to improve these specific cognitive functions. METHODS: The deficits in cognitive flexibility, working memory and planning ability were interpreted as reflecting executive cognitive processing impairments secondary to prefrontal neural system dysfunction. Following the 'process specific' approach, it was considered important to develop tasks that hypothesised the exercise of these cognitive abilities and the more molecular information processes thought to be fundamental to these abilities. Care was taken to ensure that all tasks involved the practice of processes thought to activate frontal/prefrontal neural systems. Attentional, visual, verbal, conceptual, motor and fine motor tasks were considered important for each process area in order to involve as many functional modalities as possible. RESULTS: A program comprising cognitive shift, working memory and planning modules was developed. Conducted over 11 weeks, four modules were of 2 weeks' duration, and the fifth of 3 weeks' duration. Four individual 1 hour training sessions were conducted each week. Core elements of the modules are described. CONCLUSION: Consisting predominantly of pencil and paper information processing exercises, all of the training exercises are presented in the volumes of the Frontal/Executive Program. The program appears to be user-friendly with therapists now successfully delivering the program, in its entirety, to schizophrenia patients. Should future studies replicate preliminary findings of improved neurocognitive performance following training with the program, such findings would have important implications for the treatment of schizophrenia.

Cognition Disorders↗

PubMed1986

Pattern of eyelid motion predictive of decision errors during drowsiness: oculomotor indices of altered states.

Sequential patterns of eye and eyelid motion were identified in seven subjects performing a modified serial probe recognition task under drowsy conditions. Using simultaneous EOG and video recordings, eyelid motion was divided into components above, within, and below the pupil and the durations in sequence were recorded. A serial probe recognition task was modified to allow for distinguishing decision errors from attention errors. Decision errors were found to be more frequent following a downward shift in the gaze angle which the eyelid closing sequence was reduced from a five element to a three element sequence. The velocity of the eyelid moving over the pupil during decision errors was slow in the closing and fast in the reopening phase, while on decision correct trials it was fast in closing and slower in reopening. Due to the high variability of eyelid motion under drowsy conditions these findings were only marginally significant. When a five element blink occurred, the velocity of the lid over pupil motion component of these endogenous eye blinks was significantly faster on decision correct than on decision error trials. Furthermore, the highly variable, long duration closings associated with the decision response produced slow eye movements in the horizontal plane (SEM) which were more frequent and significantly longer in duration on decision error versus decision correct responses.

Blinking↗

PubMed1998

Adaptation is automatic.

Two experiments were used to test whether selective adaptation for speech occurs automatically or instead requires attentional resources. A control condition demonstrated the usual large identification shifts caused by repeatedly presenting an adapting sound (/wa/, with listeners identifying members of a /ba/-/wa/ test series). Two types of distractor tasks were used: (1) Subjects did a rapid series of arithmetic problems during the adaptation periods (Experiments 1 and 2), or (2) they made a series of rhyming judgments, requiring phonetic coding (Experiment 2). A control experiment (Experiment 3) demonstrated that these tasks normally impose a heavy attentional cost on phonetic processing. Despite this, for both experimental conditions, the observed adaptation effect was just as large as in the control condition. This result indicates that adaptation is automatic, operating at an early, preattentive level. The implications of these results for current models of speech perception are discussed.

Adaptation, Psychological↗

PubMed2001

The role of nursing unit managers in educating nurses.

This paper presents the findings of a work sampling study undertaken in New South Wales (Australia) to ascertain the amount of time spent by nursing unit managers directly educating nurses. The results indicate that they spend very little time in teaching, traditionally one of their role tasks. It is argued that their teaching at unit level should focus on their role as leader, mentor, preceptor and coach. This role shift needs to be articulated to managers and nurses to minimise confusion over the role and to ensure that direct teaching is placed into the hands of expert clinicians.

Education, Nursing↗

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