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 1,063 records · Page 59Linked to original sources

PubMed2006

Working memory and proverb comprehension in adolescents with traumatic brain injury: a preliminary investigation.

PRIMARY OBJECTIVE: This study investigated the relationship between working memory and comprehension of low-familiarity proverbs in adolescents with traumatic brain injury (TBI). METHODS AND PROCEDURES: Ten adolescents, aged 12-21 years who had suffered a TBI prior to the age of 10 years and 10 individually age-matched peers with typical development participated in the study. The participants listened to short paragraphs containing a proverb and interpreted the meaning of the proverb using a forced-choice task. In addition, participants engaged in a task that evaluated working memory ability. MAIN OUTCOMES AND RESULTS: Analysis revealed that individuals with TBI differed from their non-injured peers in their understanding of proverbs. In addition, working memory capacity influenced performance for all participants. CONCLUSIONS: The importance of considering working memory when evaluating figurative language comprehension in adolescents with TBI is highlighted. Implications for future research, particularly with regard to varying working memory and task demands, are considered.

Adolescent↗

PubMedDate not supplied

Age differences in components of metamemory.

Young adults (N = 58) and older adults (N = 55) answered 30 questions extracted from three dimensions of the Metamemory in Adulthood (MIA) questionnaire: Capacity, Task and Strategy. The older participants scored significantly lower on the Capacity dimension, indicating that they report having greater difficulty in everyday memory situations. There was no age difference on any item in the Task dimension; both groups were equally knowledgeable about memory task demands. Responses to Strategy items varied with type of strategy: younger adults were more likely than older adults to report the use of encoding strategies, while older adults reported significantly more use of strategies which involved planning and organization. A further group of employed young adults (N = 26) was added to clarify the respective roles of aging and environmental demands on strategy use. The findings suggest that both changes in lifestyle and the effects of aging per se play some part in the use of particular memory strategies.

Adolescent↗

PubMed2006

The significance of clumsy gestures in apraxia following a left hemisphere stroke.

Individuals who sustain a cerebrovascular accident (CVA) in the dominant (typically left) hemisphere, are at increased risk of developing motor skill deficits due to motor-sensory impairments, as well as cognitive impairments (e.g., apraxia). Clumsiness is a central component affecting motor skills in individuals with a left hemisphere CVA (LCVA). The term "clumsiness" however, has not been adequately operationalised in the apraxia literature in clinical terms, thereby making diagnosis difficult and its contribution to apraxic disorders uncertain. Accordingly, in this study "clumsiness" was explicitly defined by establishing a set of four criteria. The non-dominant (left) hand movements of three groups of participants were examined: 10 individuals with limb-apraxia (APX); 8 individuals without limb apraxia who had sustained a LCVA (NAPX); and 19 healthy individuals without a history of brain impairment (NBD). Performance was examined on four sets of motor tasks, including a conventional praxis test, basic perceptual-motor co-ordination and fine movement tasks, and a naturalistic actions test. A striking finding that emerged was that clumsy errors occurred frequently in all groups, including the NBD group, particularly on the praxis and fine motor tasks. In terms of quantity of clumsy errors emitted, the APX group made significantly more clumsy gestures across all four tasks in comparison to the NBD group. No differences emerged between the two clinical groups, however, in terms of total clumsy gestures emitted on the naturalistic action tasks, or the type of clumsy errors emitted on the fine motor tasks. Thus, frequency and types of clumsy gestures were partly determined by task demands. These results highlight the need to consider the contribution of clumsy gestures in limb functioning following hemispheric brain damage. In broad terms, these findings emphasise the importance of adopting more detailed analyses of movement errors in apraxia and assessments of cognitive-based motor functioning following brain impairment.

Aged↗

PubMed2004

Mood and cognitive performance effects of "energy" drink constituents: caffeine, glucose and carbonation.

Three studies using healthy volunteers (n = 271) investigated the effects of caffeine, carbohydrates and carbonation in functional "energy" drinks (EDs) with the aim of determining their benefit in every-day life. The results showed caffeine to be the main ED constituent responsible for the effects found, with possible minor, relatively weak effects of carbohydrates. EDs were found to improve and/or maintain mood and performance during fatiguing and cognitively demanding tasks relative to placebo. In terms of absolute values, EDs maintained levels of arousal compared to a deterioration in arousal where placebo was consumed. These effects were found in caffeine-deprived participants, and so may be largely due to "withdrawal reversal". There were only minor differences in the effects of water vs. "sensory-matched" placebo, supporting previous findings indicating that the type of placebo does not alter the conclusions drawn about the effects of the full ED. Finally, carbonation had various effects on mood, some of which were present immediately following consumption, others were consistent with slower absorption of caffeine (and possibly carbohydrates) from carbonated drinks.

Adolescent↗

PubMed2005

Beyond verbal fluency: investigating the long-term effects of bilateral subthalamic (STN) deep brain stimulation (DBS) on language function in two cases.

Cognitive functioning has been described as largely impervious to chronic STN-DBS administered over 12-month periods. In relation to the domain of language, however, the effects of STN-DBS are yet to be thoroughly delineated. Verbal fluency tasks represent an almost exclusively applied index of linguistic proficiency relative to neuropsychological research within this population. Comprehensive investigations of the impact of STN-DBS on language function, however, have never been undertaken. The more precise elucidation of the role of the STN in the mediation of language processes, by way of assessments which probe language comprehension and production mechanisms, served as the primary focus of this research. Longitudinal analysis also afforded consideration of the way in which cognitive-linguistic circuits respond to STN-DBS over time. Bilateral STN-DBS primarily effected clinically reliable fluctuations (i.e., both improvements and declines) in performance in both subjects on tasks demanding cognitive-linguistic flexibility in the formulation and comprehension of complex language. Of particular note, both subjects demonstrated a cumulative increase in the proportion of reliable post-operative improvements achieved over time. The findings of this research lend support to models of subcortical participation in language which endorse a role for the STN, and suggest that bilateral STN-DBS may serve to enhance the proficiency of basal ganglia-thalamocortical linguistic circuits over time.

Aged↗

PubMed2006

Effects of embedded instruction versus discrete-trial training on self-injury, correct responding, and mood in a child with autism.

BACKGROUND: Embedded instruction and discrete-trial training are both recommended for teaching children with autism, but there is little research available comparing the two. The present study compared embedded instruction with discrete-trial training for a 12-year-old boy with autism. METHOD: An initial functional analysis indicated that the boy's self-injury was maintained by escape from task demands. Instructional sessions to teach adaptive behaviours were conducted under two conditions: (i) during embedded instruction, learning trials were inserted into ongoing activities at a rate of approximately 1.5 per minute; (ii) during discrete-trial training, instructional opportunities were incorporated into structured sessions at a rate of 4 per minute. In both conditions, the system of least prompts was used to teach relevant target responses. Effects of the two teaching formats were evaluated using an ABABA design. RESULTS: Higher rates of self-injury and fewer correct responses occurred during discrete-trial training. Mood ratings were also lower during discrete-trial training. CONCLUSIONS: The results suggest that self-injury, correct responding, and mood may be sensitive to the type of instructional format. Although discrete-trial training can be highly effective, it may be preferable to start with embedded instruction when the child presents with self-injurious escape behaviour.

Adaptation, Psychological↗

PubMed2005

Compromised arterial oxygen saturation in elderly asthma sufferers results in selective cognitive impairment.

Forty elderly patients with asthma or chronic obstructive pulmonary disorder (COPD) were compared to a comparison group of forty age-matched healthy volunteers on a range of measures of cognitive performance, and levels of arterial haemoglobin oxygen saturation recorded. Members of the patient group were found to have significantly lower oxygen saturation compared to the comparison group, and performed significantly poorer on tests of delayed word recall and serial subtractions, but not on other tasks. Correlational analysis between participants' oxygen saturation levels and test scores across the whole sample indicated significant positive relationships existed for the digit symbol substitution and serial subtractions tasks. The results are discussed in terms of cerebral oxygen delivery, glucose metabolism, age related cognitive decline, and relative task demands.

Aged↗

PubMed2006

Memory performance profile in occupational chronic solvent encephalopathy suggests working memory dysfunction.

This pilot study characterizes memory functioning of 11 men with occupational chronic solvent encephalopathy (CSE). Pattern (PRM) and spatial recognition (SRM), spatial span (SSP), spatial working memory (SWM), and paired associate learning (PAL) from Cambridge Neuropsychological Test Automated Battery were performed twice. The most sensitive variables to show impairment were PAL trials, SRM total correct, and SWM number of between-search errors. The majority of the CSE patients demonstrated mild deficits. The most persistent dysfunction was in tasks demanding working memory processing, which predicted well the CSE status. Qualitatively, the memory deficits resemble those seen in moderate or severe Parkinson's disease.

Association Learning↗

PubMed2006

Self-reported and test-based mobility limitations in a representative sample of Finns aged 30+.

AIMS: The object of the present study was to acquire a comprehensive and accurate picture of mobility limitations in the Finnish adult population. METHODS: A nationally representative sample of 8,028 persons aged 30+ with high participation was interviewed and examined in the Health 2000 Survey conducted in 2000-01. Mobility limitations were measured by self-reports and performance tests. RESULTS: Perceived running difficulties were already common among persons in middle age, while difficulties in moving about indoors were frequent only among persons aged 75+. A third of women and a fifth of men aged 55+ could not reach a walking speed of 1.2 m/s. Working-aged women were more limited than men only in physically demanding tasks, but in the elderly the gender difference was evident in most mobility tasks. A substantial disagreement was found between the self-reported and test-based indicators in stair climbing. Supplementary data collection, carried out to increase participation in the health examination, as well as inclusion of institutionalized persons, provided a more complete estimate of the prevalence of mobility limitations among the elderly. CONCLUSIONS: Both self-reported and performance-based indicators are needed to achieve a comprehensive view of disability and its variation between population groups. Exclusion of institutionalized persons and low participation lead to underestimation of the occurrence of limitations. The number of persons suffering from mobility problems will increase with ageing of the population, which accentuates the importance of early intervention to maintain functional ability, especially in women.

Activities of Daily Living↗

PubMed2004

Nothing out of the ordinary: advanced fertility nursing practice.

This paper discusses data from a case study of fertility nursing practice. An ethnographic case study approach using participant observation and nine semi-structured interviews with staff and patients was undertaken. The data were analysed thematically and these themes are discussed in this paper. We present the meaning a small group of nurses working in a fertility unit in the UK attach to new roles and the ways in which changes in practice may be influenced. The nurses in this study believed that nature of the task demanded changes to practice and they identified personal, interpersonal and socio-cultural factors which influenced these changes. These new roles facilitated greater continuity of care for patients. This paper discusses the effects of these new roles on knowing and intimacy in nurse - patient relationships. The data suggests that new nursing roles, which are based on "traditional" nursing and "new" technical skills, are fragile and may not be shared across a professional community.

Anthropology, Cultural↗

PubMed1997

On the genetics and measurement of human handedness.

Lateral preferences in humans and other primates may be a key to many important issues in biology and psychology. There is strong evidence that the representation of language functions in the cerebral cortex is different in left-handed (LH) people than in right-handed (RH) people, and an understanding of handedness may lead to valuable clues as to how the brain becomes organised in the way that it does. Although there are clearly cultural effects that influence manual activities, there is nevertheless evidence that human handedness and other lateralities are at least in part genetically determined: compared with two RH parents, one RH and one LH parent are 2-3 times more likely to have an LH child, and two LH parents are 3-4 times more likely to have an LH child. Thus, one might wish to investigate the genetics of laterality with the goal of understanding the biological mechanisms that lead to the preferential use of one hand (or eye or foot). One may also see links between human handedness and footedness and the motor asymmetries found in many nonhuman primate species, and perhaps in lower mammals as well. From this perspective, one might see the study of human laterality as relevant to evolutionary biology. Investigators of both human and nonhuman asymmetries have to grapple with such difficult measurement issues as the relations between preference and performance, and the influences of postural and task demands, and have much to offer each other in the quest for the nature of laterality. Our recent work seems to indicate that the various sensory and motor lateralities may be related, in humans, but not in a simple way. In future work, the challenge will be to identify the relations between the various laterality ''profiles'' and patterns of functional cerebral organisation.

Journal Article↗

PubMed1998

Determinants of positive and negative generation effects in free recall.

Better retention of self-produced as opposed to experimenter-presented material is called generation effect; the reverse phenomenon is the negative generation effect. Both are found in intentional-learning experiments in which generating versus reading is manipulated between subjects. The present article presents an overview of those findings and aims at clarifying the conditions under which these effects emerge. Experiments 1 and 2 demonstrate that if cue-target relations are manipulated within one list, a negative generation effect in free recall can be obtained for all items, no matter which cue-target relation they bear. In Experiment 3, cue-target relations were manipulated between lists. Here, a negative generation effect in free recall was found only in lists in which items were cued with words that mismatched the inter-target relations, whereas a positive generation effect was observed in those lists in which the generation cues matched the inter-target relations. A subsequent cued-recall test demonstrated that in cases of mismatch of relations, participants in the generate condition process cue-target relations at the expense of inter-target relations. The three-factor theory can be integrated with the task-demand account in a transfer-appropriate processing framework to accommodate these findings.

Attention↗

PubMed2001

On the strategic modulation of the time course of facilitation and inhibition of return.

In studies of exogenous attentional orienting, response times for targets at previously cued locations are often longer than those for targets at previously uncued locations. This effect is known widely as inhibition of return (IOR). There has been debate as to whether IOR can be observed in discrimination as well as detection tasks. The experiments reported here confirm that IOR can be observed when target discrimination is required and that the cue-target interval at which IOR is observed is often longer in discrimination than in detection tasks. The results also demonstrate that the later emergence of IOR is related to perceptual discrimination rather than to response selection differences between discrimination and detection tasks. More difficult discrimination tasks lengthen the SOA at which IOR emerges. In contrast, increasing task difficulty by adding a distractor to the location opposite the target shortens the SOA at which IOR emerges. Together, the results reveal an adaptive interaction between exogenous and endogenous attentional systems, in which the action of the orienting (exogenous) system is modulated endogenously in accord with task demands.

Attention↗

PubMed1998

Perceptual and conceptual priming of individual words in coherent texts.

This study explores implicit memory within the domain of text processing. Three experiments were designed to study priming in word-fragment completion, word-stem completion, and free association tests following presentation of target words in the context of a coherent text. In order to examine the time course of perceptual and conceptual processes we investigated the priming effects by manipulating the perceptual context in which the target words had been read and the time given to the subjects for each test-cue. Three main results emerged. First, we found a significant priming effect in the three implicit tests for words previously studied in a text. Second, the magnitude of the priming effect only varied when the task demands required perceptual and conceptual processing, as was the case with the completion tests. Third, priming effects did not depend on subjects' comprehension of the text read. These results are discussed in the framework of the transfer-appropriate processing view proposed by Roediger, Weldon, and Challis (1989).

Concept Formation↗

PubMed2002

Carbohydrate administration during a day of sustained aerobic activity improves vigilance, as assessed by a novel ambulatory monitoring device, and mood.

BACKGROUND: The brain requires a continuous supply of glucose to function adequately. During aerobic exercise, peripheral glucose requirements increase and carbohydrate supplementation improves physical performance. The brain's utilization of glucose also increases during aerobic exercise. However, the effects of energy supplementation on cognitive function during sustained aerobic exercise are not well characterized. OBJECTIVE: The effects of energy supplementation, as liquid carbohydrate, on cognitive function during sustained aerobic activity were examined. DESIGN: A double-blind, placebo-controlled, between-subjects design was used. Young, healthy men (n = 143) were randomly assigned to 1 of 3 treatment groups. The groups received either a 6% (by vol) carbohydrate (35.1 kJ/kg), 12% (by vol) carbohydrate (70.2 kJ/kg), or placebo beverage in 6 isovolumic doses, and all groups consumed 2 meals (3200 kJ). Over the 10-h study, the subjects performed physically demanding tasks, including a 19.3-km road march and two 4.8-km runs, interspersed with rest and other activities. Wrist-worn vigilance monitors, which emitted auditory stimuli (20/h) to which the subjects responded as rapidly as possible, and a standardized self-report mood questionnaire were used to assess cognitive function. RESULTS: Vigilance consistently improved with supplemental carbohydrates in a dose-related manner; the 12% carbohydrate group performed the best and the placebo group the worst (P < 0.001). Mood-questionnaire results corroborated the results from the monitors; the subjects who received carbohydrates reported less confusion (P = 0.040) and greater vigor (P = 0.025) than did those who received the placebo. CONCLUSIONS: Supplemental carbohydrate beverages enhance vigilance and mood during sustained physical activity and interspersed rest. In addition, ambulatory monitoring devices can continuously assess the effects of nutritional factors on cognition as individuals conduct their daily activities or participate in experiments.

Acoustic Stimulation↗

PubMed2026

Accelerated long-read variant calling with Clair3 for whole-genome sequencing.

SUMMARY: The rapid growth of genomic data and increasing adoption of long-read sequencing technologies have rendered variant calling one of the most computationally demanding tasks in genomic analysis. Although deep learning-based methods currently outperform conventional approaches in distinguishing true variants from complex sequencing noise, they impose prohibitive computational and time requirements. To address this limitation, we present a computational framework based on Clair3 that integrates parallelized feature generation, enhanced variant phasing, in-memory read haplotagging, and GPU-accelerated neural network inference to accelerate variant calling. By dynamically optimizing the use of both GPU and CPU resources, our method achieves substantial runtime improvements without compromising accuracy. We evaluated our framework across a range of sequencing depths, diverse samples, and multiple hardware configurations. Our results demonstrate that the optimized pipeline completes variant calling for a 30× whole-genome sequence in 12-20 minutes using standard computational resources (32 CPU threads and one NVIDIA GPU), and in 12-15 minutes on an Apple Mac Studio (32 threads), which is ∼10-20-fold speedup compared with its initial release. In addition to exceptional efficiency, our method maintains state-of-the-art accuracy, achieving SNP F1-scores of 99.32% and 99.70% on 30× ONT and PacBio GIAB HG003 datasets, respectively. This work introduces a rapid, accurate, and scalable variant calling framework that effectively supports large-cohort genomic studies and time-sensitive clinical applications. AVAILABILITY AND IMPLEMENTATION: The accelerated implementation of Clair3 is open source and available at: https://github.com/HKU-BAL/Clair3/tree/gpu.

Whole Genome Sequencing↗

PubMed2004

Wnt pathway curation using automated natural language processing: combining statistical methods with partial and full parse for knowledge extraction.

MOTIVATION: Wnt signaling is a very active area of research with highly relevant publications appearing at a rate of more than one per day. Building and maintaining databases describing signal transduction networks is a time-consuming and demanding task that requires careful literature analysis and extensive domain-specific knowledge. For instance, more than 50 factors involved in Wnt signal transduction have been identified as of late 2003. In this work we describe a natural language processing (NLP) system that is able to identify references to biological interaction networks in free text and automatically assembles a protein association and interaction map. RESULTS: A 'gold standard' set of names and assertions was derived by manual scanning of the Wnt genes website (http://www.stanford.edu/~rnusse/wntwindow.html) including 53 interactions involved in Wnt signaling. This system was used to analyze a corpus of peer-reviewed articles related to Wnt signaling including 3369 Pubmed and 1230 full text papers. Names for key Wnt-pathway associated proteins and biological entities are identified using a chi-squared analysis of noun phrases over-represented in the Wnt literature as compared to the general signal transduction literature. Interestingly, we identified several instances where generic terms were used on the website when more specific terms occur in the literature, and one typographic error on the Wnt canonical pathway. Using the named entity list and performing an exhaustive assertion extraction of the corpus, 34 of the 53 interactions in the 'gold standard' Wnt signaling set were successfully identified (64% recall). In addition, the automated extraction found several interactions involving key Wnt-related molecules which were missing or different from those in the canonical diagram, and these were confirmed by manual review of the text. These results suggest that a combination of NLP techniques for information extraction can form a useful first-pass tool for assisting human annotation and maintenance of signal pathway databases. AVAILABILITY: The pipeline software components are freely available on request to the authors. CONTACT: dstates@umich.edu SUPPLEMENTARY INFORMATION: http://stateslab.bioinformatics.med.umich.edu/software.html.

Animals↗

PubMed2006

Planning optimal measurements of isotopomer distributions for estimation of metabolic fluxes.

MOTIVATION: Flux estimation using isotopomer information of metabolites is currently the most reliable method to obtain quantitative estimates of the activity of metabolic pathways. However, the development of isotopomer measurement techniques for intermediate metabolites is a demanding task. Careful planning of isotopomer measurements is thus needed to maximize the available flux information while minimizing the experimental effort. RESULTS: In this paper we study the question of finding the smallest subset of metabolites to measure that ensure the same level of isotopomer information as the measurement of every metabolite in the metabolic network. We study the computational complexity of this optimization problem in the case of the so-called positional enrichment data, give methods for obtaining exact and fast approximate solutions, and evaluate empirically the efficacy of the proposed methods by analyzing a metabolic network that models the central carbon metabolism of Saccharomyces cerevisiae.

Algorithms↗