SEARCH · PubMed Health

Results for “Task demands”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources

PubMed2004

[The system of informal caregiving as inequality].

In our setting, it is families, not the health and social services, who play the greatest role in providing continuous care to persons in need of such services. Informal health care poses two key questions with regard to the issue of equity: differences in the burdens borne by men and women, which contribute to gender inequality and, depending on their educational and socio-economic level, inequities in their ability to choose and gain access to needed resources and support services, thus contributing to social class inequalities. Distributing the burden of caregiving between men and women, and between the family and the state, constitutes a crucial debate in public health. This study analyzes the concept and characteristics of informal care, provides data on its dimensions in our setting, and analyzes the profile of caregivers, as well as the work they do and the impact it has on their lives. Finally, it presents currently existing models and support strategies for informal caregivers. It is largely women who assume the principal role of providing informal care, undertaking the most difficult and demanding tasks and dedicating the largest share of their time to them. As a result, women bear an elevated cost in their lives in terms of health, quality of life, access to employment and professional development, social relations, availability of time for themselves, and economic repercussions. Unemployed, under-educated women from the least privileged social classes constitute the largest group of informal caregivers in our country. Any policies aimed at supporting those who provide such care should keep in mind the unequal point from which they start and be evaluated in terms of their impact on gender and social class inequality.

Caregivers↗

PubMedDate not supplied

Predictors of cognitive decline in the early stage of probable Alzheimer's disease.

Several papers have attempted to find neurological and neuropsychological predictors of progression in Alzheimer's disease (AD) till now. Despite this quite large amount of works, different and not univocal conclusions have been reported in this field. Different study samples, different end-points and differences in statistical methods can explain much of the inconsistency in the results obtained. In our study, AD patients were examined in a very early stage of the disease to avoid any possible risk to examine subjects at different times of evolution. All the patients underwent an extensive neuropsychological test battery twice (baseline and follow-up) spaced out over about 1 year and were divided into two groups of fast decliners (FD) and slow decliners (SD) on the basis of their rate of decay at the MMSE score. Verbal memory tests, mental control abilities and attention-demanding tasks seem to play a pivotal role in distinguishing the two groups of subjects in the early stage of the disease. Moreover, FD patients show a worse performance than SD at the baseline in most of the cognitive domains explored. In conclusion, different subtypes of AD do exist and an important predictor of progression is represented by the severity of the cognitive impairment at the onset.

Aged↗

PubMed2001

Mammary epithelial cell and adipocyte co-culture in a 3-D matrix: the first step towards tissue-engineered human breast tissue.

Reconstruction of the female breast after cancer surgery is a demanding task where the methods used today suffer from several disadvantages. In the present study we have investigated the possibility to use tissue engineering methods to regenerate human autologous breast tissue. Human mammary epithelial cells and preadipocytes were derived from breast tissue biopsies from healthy women undergoing reduction mammoplasty, and the two celltypes were co-cultured with conventional cell culture methods as well as in 3-D matrices. The study shows that it is possible to harvest both human mammary epithelial cells and preadipocytes in a single session, propagate several subcultures, and that the cells maintain a normal intercellular distribution and growth-pattern when co-cultured in a 3-D collagen gel. We propose that growth and formation of a tissue closely resembling normal human breast tissue be readily obtained in the described in vitro cell culture set-up using basic tissue engineering principles. This concept may be of great importance in the development of new methods for reconstruction of the human breast.

Adipocytes↗

PubMed1977

Time perception and hemodialysis.

Subtle alterations in neurological function are often difficult to identify and even harder to quantitate. The identification of a neurotoxic state existing before overt behavioral changes occur has eluded quantification. It was hypothesized that a challenging signal-detection procedure would be used to assess neurological function of dialysis patients and other subjects, the degree of uremic toxicity occuring during an interdialytic interval, and the effects of neuroactive drugs. A vigilance task demanding the detection of an irregularly flashing light from a matrix of regularly flashing lights was administered to 3 groups of 15 men: patients undergoing maintenance hemodialysis, patients with chronic illness and no kidney disease, and healthy subjects. The procedure was found to yield a reliable measure; average test-retest correlation was 0.93, which differentiated not only within the hemodialysis cycle (p less than 0.001), between groups (p less than 0.001), but was also related to the recency of neuroactive drugs ingested (p less than 0.01).

Arthritis↗

PubMed2001

Motor learning of compatible and incompatible visuomotor maps.

Brain imaging studies demonstrate increasing activity in limb motor areas during early motor skill learning, consistent with functional reorganization occurring at the motor output level. Nevertheless, behavioral studies reveal that visually guided skills can also be learned with respect to target location or possibly eye movements. The current experiments examined motor learning under compatible and incompatible perceptual/motor conditions to identify brain areas involved in different perceptual-motor transformations. Subjects tracked a continuously moving target with a joystick-controlled cursor. The target moved in a repeating sequence embedded within random movements to block sequence awareness. Psychophysical studies of behavioral transfer from incompatible (joystick and cursor moving in opposite directions) to compatible tracking established that incompatible learning was occurring with respect to target location. Positron emission tomography (PET) functional imaging of compatible learning identified increasing activity throughout the precentral gyrus, maximal in the arm area. Incompatible learning also led to increasing activity in the precentral gyrus, maximal in the putative frontal eye fields. When the incompatible task was switched to a compatible response and the previously learned sequence was reintroduced, there was an increase in arm motor cortex. The results show that learning-related increases of brain activity are dynamic, with recruitment of multiple motor output areas, contingent on task demands. Visually guided motor sequences can be linked to either oculomotor or arm motor areas. Rather than identifying changes of motor output maps, the data from imaging experiments may better reflect modulation of inputs to multiple motor areas.

Adult↗

PubMed2004

The faces of development: a review of early face processing over childhood.

The understanding of the adult proficiency in recognizing and extracting information from faces is still limited despite the number of studies over the last decade. Our knowledge on the development of these capacities is even more restricted, as only a handful of such studies exist. Here we present a combined reanalysis of four ERP studies in children from 4 to 15 years of age and adults (n = 424, across the studies), which investigated face processing in implicit and explicit tasks. We restricted these analyses to what was common across studies: early ERP components and upright face processing across all four studies and the inversion effect, investigated in three of the studies. These data demonstrated that processing faces implicates very rapid neural activity, even in young children--at the P1 component--with protracted age-related change in both P1 and N170, that were sensitive to the different task demands. Inversion produced latency and amplitude effects on the P1 from the youngest group, but on N170 only starting in mid childhood. These developmental data suggest that there are functionally different sources of the P1 and N170, related to the processing of different aspects of faces.

Adolescent↗

PubMed2004

Implicit and explicit evaluation: FMRI correlates of valence, emotional intensity, and control in the processing of attitudes.

Previous work suggests that explicit and implicit evaluations (good-bad) involve somewhat different neural circuits that process different dimensions such as valence, emotional intensity, and complexity. To better understand these differences, we used functional magnetic resonance imaging to identify brain regions that respond differentially to such dimensions depending on whether or not an explicit evaluation is required. Participants made either good-bad judgments (evaluative) or abstract-concrete judgments (not explicitly evaluative) about socially relevant concepts (e. g., ''murder,'' ''happiness,'' ''abortion,'' ''welfare''). After scanning, participants rated the concepts for goodness, badness, emotional intensity, and how much they tried to control their evaluation of the concept. Amygdala activation correlated with emotional intensity and right insula activation correlated with valence in both tasks, indicating that these aspects of stimuli were processed by these areas regardless of intention. In contrast, for the explicitly evaluative good-bad task only, activity in the anterior cingulate, frontal pole, and lateral areas of the orbital frontal cortex correlated with ratings of control, which in turn were correlated with a measure of ambivalence. These results highlight that evaluations are the consequence of complex circuits that vary depending on task demands.

Amygdala↗

PubMedDate not supplied

Separable routes to human memory formation: dissociating task and material contributions in the prefrontal cortex.

The present study used fMRI to investigate functional dissociations across frontal regions during incidental memory formation. Subjects were imaged while encoding materials with differential access to phonological codes (nonfamous faces and nameable famous faces) under task conditions that encouraged elaborate (deep) or superficial (shallow) encoding strategies. Results revealed a functional dissociation between dorsal posterior regions of the prefrontal cortex (BA 6/44) that were sensitive to material type (famous vs. nonfamous), irrespective of the encoding task, and ventral anterior regions of the prefrontal cortex (BA 45/47) that were uniquely sensitive to task demands (deep vs. shallow), regardless of material type. Further, subjects realized a memorial advantage to the extent that they recruited these dissociable frontal regions. These results demonstrate a posterior/anterior dichotomy in the frontal cortex that underlies separable code-based routes to human memory formation.

Adolescent↗

PubMed2005

Right hemisphere activation of joke-related information: an event-related brain potential study.

Two studies tested the hypothesis that the right hemisphere engages in relatively coarse semantic coding that aids high-level language tasks such as joke comprehension. Scalprecorded event-related brain potentials (ERPs) were collected as healthy adults read probe words (CRAZY) preceded either by jokes or nonfunny controls ("Everyone had so much fun jumping into the swimming pool, we decided to put in a little water/platform"). Probes were related to the meaning of the jokes, but not the controls. In Experiment 1a, with central presentation, probes following jokes (related) elicited less negative ERPs 300-700 msec postonset (N400) than did probes following nonfunny controls (unrelated). This finding suggests related probes were primed by the jokes. In addition, unrelated probes elicited a larger anterior positivity 700-900 msec than did related, as irrelevant stimuli impacted control processes invoked by task demands. In Experiment 1b, probes (CRAZY) were preceded only by sentence-final words from jokes (water) or controls (platform). No ERP effects were observed in Experiment 1b, suggesting the N400 priming effect and the anterior positivity observed in Experiment 1a ref lect semantic activations at the discourse level. To assess hemispheric differences in semantic activations, in Experiment 2, ERPs were recorded as participants read probe words presented in their left and right visual fields (LVF and RVF, respectively). Probes elicited a smaller N400 component when preceded by jokes than controls. This N400 priming effect was larger with presentation to the LVF, suggesting joke-relevant information was more active in the right hemisphere. The anterior positivity was observed with RVF but not LVF presentation, suggesting an important role for the left hemisphere in controlled retrieval in language comprehension.

Acoustic Stimulation↗

PubMed2006

Visual grouping and the focusing of attention induce gamma-band oscillations at different frequencies in human magnetoencephalogram signals.

Neural oscillatory synchrony could implement grouping processes, act as an attentional filter, or foster the storage of information in short-term memory. Do these findings indicate that oscillatory synchrony is an unspecific epiphenomenon occurring in any demanding task, or that oscillatory synchrony is a fundamental mechanism involved whenever neural cooperation is requested? If the latter hypothesis is true, then oscillatory synchrony should be specific, with distinct visual processes eliciting different types of oscillations. We recorded magnetoencephalogram (MEG) signals while manipulating the grouping properties of a visual display on the one hand, and the focusing of attention to memorize part of this display on the other hand. Grouping-related gamma oscillations were present in all conditions but modulated by the grouping properties of the stimulus (one or two groups) in the high gamma-band (70-120 Hz) at central occipital locations. Attention-related gamma oscillations appeared as an additional component whenever attentional focusing was requested in the low gamma-band (44-66 Hz) at parietal locations. Our results thus reveal the existence of a functional specialization in the gamma range, with grouping-related oscillations showing up at higher frequencies than attention-related oscillations. The pattern of oscillatory synchrony is thus specific of the visual process it is associated with. Our results further suggest that both grouping processes and focused attention rely on a common implementation process, namely, gamma-band oscillatory synchrony, a finding that could account for the fact that coherent percepts are more likely to catch attention than incoherent ones.

Adult↗

PubMed2005

The earliest EEG signatures of object recognition in a cued-target task are postsensory.

Recent experiments have demonstrated early target minus nontarget differences in the human event-related potential (ERP) during visual object recognition tasks. It is unclear whether these differences reflect high-level visual processes, effectively indexing the speed of object recognition, or whether they arise from postsensory decision processes, leaving the actual time of object recognition uncertain. Here we report three sets of ERP experiments designed to determine what processes underlie the target minus nontarget difference signals seen in visual cued-target paradigms. We demonstrate that the same difference signals are present when the target match is made to word stimuli as well as to object stimuli, suggesting that the disparate mechanisms involved in letter string and object processing are not directly responsible for the signals. We also find that the amplitude of these signals can be reduced by increasing trial difficulty in three different ways: image difficulty, level of semantic categorization, and overall task demands. In many respects, the difference signal is similar to the postrecognition P300. Together, these results suggest that the target minus nontarget difference does not reflect object recognition per se, but rather postsensory decision processes.

Adolescent↗

PubMed1996

Event-related potentials in schizotypal personality disorder.

This study examined whether abnormalities in event-related potentials (ERPs), reported in schizophrenia, extend to patients with schizotypal personality disorder (SPD). Auditory ERPs in an oddball paradigm were obtained in 19 SPD patients, 17 schizophrenic patients, and 20 normal control subjects (NCs). Schizophrenic patients had lower P300 amplitude than NCs; the P300 amplitude of SPD patients was intermediate, showing a linear trend but not a significant group difference. P200 amplitudes showed a similar trend. SPD patients had N100 and N200 amplitudes intermediate to schizophrenic patients and NCs, without significant group differences. Results suggest diminished P300 amplitude may not be as prominent in SPD as in schizophrenia. Studies with larger sample sizes, multiple lead assessment strategies, and more demanding tasks may further characterize ERP deficits in schizophrenia-spectrum disorders such as SPD.

Adult↗

PubMed1992

Psychoanalytic ecumenism and varieties of psychoanalytic experience.

Using the metaphor of ecumenism, the current status of psychoanalysis and the American Psychoanalytic Association is examined. The dialectical tendencies to oppose and to unify are noted in psychoanalytic theory, technique, and practice, as well as in the administrative and political life of our organization. Fostering tolerance for new hypotheses without sacrificing empirical discrimination, and promoting broad participation without lowering standards confront us as major tasks demanding continuing vigilance and effort.

Female↗

PubMed1994

Signal affects and our psychoanalytic confusion of tongues.

Difficulties psychoanalysts of different points of view have in communicating with one another are reviewed. Reexamination of the structural theory distinguishes the tripartite theory of 1923 from the signal affect model of 1926; the latter concept is traced through the post-Freudian relational points of view. This signal affect model provides a base for what the author sees as a core commonality among the diverse current theories, as well as a basis for sharper, more empirically arguable differentiation of the divergences and incompatibilities among them. The interest in and acceptance, in recent years, of Ferenczi's contributions in his 1933 paper on confusion of tongues reflect a shift in our views of psychoanalytic technique over the intervening years, toward an interactional view of the psychoanalytic process. The relational points of view have been instrumental in this shift, by direct contributions, and indirectly by challenging and inspiring the classical viewpoint to develop and change. The relational points of view, in addition to focusing on different contents, also prescribe differences in technical approach and in the climate within which an analysis is conducted, presenting valuable alternatives in clinical work. Finally, arguments are offered in favor of clinicians using multiple theoretical points of view for access to the varied clinical tasks demanded by analytic work.

Austria↗

PubMed1989

On learning ... more or less: a knowledge x process x context view of learning disabilities.

The authors review the last decade of their research on learning disabilities and conclude that knowledge x process x context is the most useful way to think about children's cognitive difficulties. According to this framework, learning disabilities is seen as a result of the interplay between a poorly elaborated knowledge base (especially in language-related domains), the biologically determined efficiencies of various microlevel processes such as encoding, and the physical and social meaning attached to performance (i.e, the context). It is suggested that this framework helps explain instances of asymmetry wherein children with learning disabilities deploy a cognitive process more or less efficiently, depending on the material and task demands. It also raises several interesting questions about the presumed "specificity" of the impairment underlying learning disablement and the possibility that these children may not differ qualitatively from nonimpaired peers, only quantitatively.

Adolescent↗

PubMed1990

Can learning disabilities be determined from working memory performance?

This study assumes that children of various academic abilities may be characterized by different patterns of memory function. To test this assumption, subgroups of children were identified through a hierarchical cluster analysis based upon a test battery of sentence span, preload, and concurrent memory demand tasks. One subtype presented a profile of children with learning disabilities showing severe memory performance deficits, while another subgroup yielded high memory and high academic performance. Four additional subtypes had variations in memory performance, which in turn reflected variations in external criteria related to reading, mathematics, and spelling performance. For each subtype, performance strengths and weaknesses were characterized within Baddeley's (1986) working memory model. The study provides partial validation for the classification of children with learning disabilities on psychometric measures according to patterns of memory performance.

Achievement↗

PubMed1990

Temporal processing in dyslexia.

The temporal processing capabilities of 15 children with dyslexia versus 15 age-matched and 15 reading-matched controls in a word identification task were examined. The hypothesis underlying the present experiment was that word recognition would be inferior in children with dyslexia, relative to controls, when the task demanded the temporal integration (sequencing) of two-syllable words. Such a hypothesis must predict that one-syllable word recognition does not distinguish between these two populations and that these effects cannot be accounted for in terms of eye movement differences. To test this hypothesis, one- and two-syllable words displayed for 100, 300, and 3,000 msec were required to be identified. The results yielded evidence of decreased accuracy of word identification by the children with dyslexia in the two-syllable, 300-msec condition, as predicted. A second experiment was unable to uncover any differences in eye movement behaviors that could account for the effects observed in the first experiment. The results are discussed in terms of potential sequential processing deficits in individuals with dyslexia.

Adolescent↗

PubMed1993

Situation specificity in attention-seeking problem behavior. A case study.

Previous research on attention-seeking problem behavior has focused on individuals who misbehaved under general conditions of low adult attention. In general, no detailed analyses were conducted to determine whether different situations involving low levels of adult attention (such as familiar vs. unfamiliar adults, setting events, or the presence or absence of peers) exacerbated or attenuated problem behavior. The current case study demonstrates that, for one adolescent, all situations involving low levels of adult attention were not equally discriminative for problem behavior. Two functional analyses concerning different situations involving low levels of adult attention were conducted. The first analysis consisted of systematically manipulating antecedent and consequence conditions related to adult attention and task demands. This analysis indicated that low levels of adult attention evoked problem behavior. The second analysis involved two different conditions presenting low levels of adult attention. In one, the adult spoke to another child; in the second, the adult spoke to another adult. This second analysis revealed that, when the adult spoke to another adult, problem behavior resulted. However, when the adult spoke to another child, problem behavior did not occur. On the basis of these functional analyses, a positive intervention was designed to reduce problem behavior. Theoretical implications related to functional analysis are discussed, and applied issues concerning functionally based treatment selection are explored.

Adolescent↗