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At least 217 records · Page 12Linked to original sources
PubMed1993

Visuomotor control of the relative movement of random-dot patterns.

A series of experiments were made on human performance in controlling optical relative movement. The aim was to test the influence of different kinds of relative movement on visually controlled steering tasks. Within adjacent displays on a computer screen random dot patterns moved in a fixed direction at continually changing speeds (Exp. 1) or at constant speed and in continually changing directions (Exp. 2). The subject was required to compensate for the unpredictable modulations of the pattern movement by means of an isometric joystick. The task was to adjust relative movements involving pure translation, symmetric convergence, divergence, or shear. Analysis indicated that the task performance was not dependent on the special kind of relative movement. However, performance was significantly higher in tasks where directionally disturbed relative movement had to be controlled compared to those situations in which relative movement varied with respect to speed.

Adult↗
PubMed1995

Explicit memory and repetition priming in dementia: evidence for a common basic mechanism underlying conscious and unconscious retrieval deficits.

The present study was designed to assess performance of Alzheimer's (AD) and Multi-infarct (MID) demented patients on the explicit and implicit versions of two memory tasks, namely Word-Stem Completion and Word-Pair Learning. Consistently with previous studies, the AD patients were deficient on the explicit and implicit versions of both tasks. In MID patients, a dissociation emerged between normal implicit and deficient explicit Word-Stem Completion. Two multiple regression analyses were performed to evaluate patients' ability on measures of lexical-semantic competence, explicit memory, and global intellective efficiency in predicting level of repetition priming. The results demonstrate a close association between explicit and implicit memory performance in AD patients but no relation between repetition priming level and measures of lexical-semantic competence or general intelligence. Overall, the results of the present study do not support previous conceptualizations suggesting that a breakdown in the structure of semantic memory is at the root of deficient priming in demented patients. Alternative interpretations of the deficient repetition priming effect in dementia, based on a common mechanism underlying conscious and unconscious retrieval deficits, are discussed.

Aged↗
PubMed1995

Treatment of Trichuris trichiura infections improves growth, spelling scores and school attendance in some children.

The effects of treating Trichuris trichiura infections were investigated in 407 Jamaican children age 6 to 12 y. The children were randomly assigned to receive treatment (albendazole) or a placebo. The outcome variables included growth, tests of reading, spelling and arithmetic, and school attendance. After 6 mo of treatment, there was no significant main effect on any of the outcomes. However, there were significant treatment-by-infection intensity interactions with spelling (P < 0.05) and body mass index (P < 0.01), and a significant treatment-by-stunting interaction with school attendance (P < 0.01). In spelling, the children with heavy infections showed improvements with treatment that approached significance (P = 0.06), whereas those with lower intensities did not. However, the children with lower infection intensities had increased body mass index with treatment (P = 0.02), although there was no difference in children with heavy infections. In school attendance, the stunted children improved with treatment (P < 0.04), whereas there was no difference in the nonstunted children. These findings suggest that in the sample of Jamaican children examined, the treatment of T. trichiura was more likely to benefit school performance in children of poor nutritional status and those with heavy infections, and to improve weight gain in children with lighter infection intensities.

Achievement↗
PubMed1999

Task decomposition analysis of intertrial free recall performance on the Rey Auditory Verbal Learning Test in normal aging and Alzheimer's disease.

Task decomposition provides supplementary data that complement traditionally computed performance indexes of multi-trial list learning. Both traditional and decomposition approaches can be combined to permit a thorough assessment of multiple aspects of learning and memory in patients with memory impairment. We applied task decomposition to investigate the relative roles of acquisition and consolidation in mediating the multi-trial learning deficit in patients with Alzheimer's disease. This goal was accomplished by decomposing recall performance across the five study-and-test trials of the Rey Auditory Verbal Learning Tests into measures that presumably tap intertrial acquisition and intertrial consolidation. As compared to matched controls, patients diagnosed with mild Alzheimer's disease showed lower gained access across trials, indicating that Alzheimer's disease impairs the ability to produce a stable memory representation of new material in long-term memory. Additionally, patients with Alzheimer's disease manifested higher lost access, which suggests that deficient consolidation leading to rapid intertrial forgetting also contributes to their poor learning. We argue that analytically decomposing learning curves will help both in uncovering the cognitive processes that underlie disease-related learning deficits in persons with memory disorders and can help to characterize potential areas for remediation.

Aged↗
PubMed1996

Assessing a virtual reality surgical skills simulator.

The Institute for Defense Analyses (IDA) was contracted to perform a military standard task analysis of laparoscopic cholecystectomy, and to study the effectiveness of a virtual reality surgical skills simulator as a tool for surgical training and as a method for recording psychomotor behavior. This report describes the purpose of the study, its design, initial results, and implications for the field of medical education.

Cholecystectomy, Laparoscopic↗
PubMed2003

British running performances in the eighteenth century.

Our aims were to improve our understanding of human performance before 1850 and to put nineteenth- and twentieth-century performances into a broader historical context. Consequently, 536 foot-races performed in Britain in the 'long' eighteenth century were identified, 53 of which were analysed in detail. The best performances at the end of the eighteenth century were compared with those at the end of the nineteenth and twentieth centuries. The data for the nineteenth century were marginally better than those for the eighteenth century up to 20 nm, but beyond that Thomas Carlisle's time, set in about 1740, of 2 hours for 21 miles was outstanding. Current records are shown to be better than earlier records at all distances from 5 km up to the marathon, the superiority being most pronounced from 15 km upwards.

History, 18th Century↗
PubMed1974

Marijuana and driving in real-life situations.

It is evident that the smoking of marijuana by human subjects does have a detrimental effect on their driving skills and performance in a restricted driving area, and that this effect is even greater under normal conditions of driving on city streets. The effect of marijuana on driving is not uniform for all subjects, however, but is in fact bidirectional; whether or not a significant decline occurs in driving ability is dependent both on the subject's capacity to compensate and on the dose of marijuana. For those subjects who improved their performance, the explanation may lie in overcompensation and possibly the sedative effect of the drug. Whereas the street portion of this study approximated normal driving conditions, it should be emphasized that the context of the driving experience een on city streets was experimental. the design of this study maximal safeguards in terms of a dual control vehicle and a driver observr; in addition, the subjects were proffessionally screened and, with rare exception, they were emotionally stable. Given the experimental setting and set, the safeguards, and the nature of the study sample, idiosyncratic behaviour that might occure under normal driving condition would be less likely to occur in a study such as this. Other identified factors might lead to more stringent conclussions regarding the effects of marijuana on driving.The first is night driving, which may be more stressful. But an even more important unanswered question is the cumulative effect of alcohol and marijuana on driving (64 percent of the study sample reported alcohol in combination with marihjuana before driving). Third, the doses of marijuana used in this study were within the range of social marijuana usage(1); more heroic doses might be taken before driving. Fourth, the effect of marijuana on reactions and decision during high speed is still another unknown. What are the recommendations that emarge from this study? Driving under the influence of marijuana should be avoided as much as should driving under the influence of alcohol. More investigation is urgently required-and high priority should be given to studies that approximate normal conditions of driving and in which alcohol and marijuana are administered to the same subjects.

Adult↗
PubMed1994

Motor and non-motor components of the Contingent Negative Variation.

To study the contribution of the Stimulus-Preceding Negativity (SPN) to the late wave of the Contingent Negative Variation (CNV), negativity was recorded preceding an instruction stimulus (S1), an instruction stimulus to which a motor response was required (S2) and a stimulus that transmitted Knowledge of Results (KR). All recorded negativities showed a centro-parietal maximum. The pre-instruction negativities tended to be larger over the left hemisphere, while a right hemisphere preponderance was found for the pre-KR negativity. Unlike the pre-S1 negativity, the pre-KR negativity may depend on affective-motivational processes. The pre-S1 negativity was small and influenced by factors other than the instruction at S1. It is concluded that the SPN contributes to the late CNV, but that this contribution was relatively small.

Adult↗
PubMed1998

A comparative approach to identify unsafe older drivers.

The identification of unsafe older drivers is a current and important challenge. In the present research, a comparative approach was used in which the on road driving errors and expert evaluations of older drivers with clinically significant declines in mental abilities (N = 155) were compared to the errors and evaluations of a normal elderly control group (N = 68) and a normal younger control group (N = 30). The results indicate that the conventional criteria used in North America for licensing new drivers is inappropriate for license removal in experienced drivers. The results also indicate that hazardous errors were the single best indicator of membership in the group of older drivers with clinical impairment. This group also differs from the two normal control groups on turn positioning errors, minor positioning errors and overcautiousness. All groups differ from each other on scanning errors. A regression analysis further indicated that the five driving errors listed above accounted for over 57% of the variance associated with global ratings provided by expert driving instructors.

Accidents, Traffic↗
PubMed1980

Language comprehension in sensorimotor stages V and VI.

A cross-sectional study of language comprehension in relation to cognitive functioning in 48 to 10-to-21 month old children, 4 at each month of age, revealed significant correlations between comprehension and five sensorimotor subscales. Age, however, was the only significant predictor in multiple regression analyses adding either age or sensorimotor subscale in second. In specific instances in which sensorimotor tasks tapped hypothetical prerequisites to specific language comprehension items, the two domains corresponded closely; but the cognitive domain was not always the first to be passed. Comprehension items were ordered from easy to hard as follows: 1) understanding single words for present people or objects; 2) for actions; 3) for absent people or objects; 4) understanding two words for the semantic relations possessor-posession, action-object, and agent-action; 5) understanding three words for agent-action-object. Implications for the Cognition Hypothesis are discussed.

Age Factors↗
PubMed1996

Profile of the musculoskeletal pain suffered by textile tufting workers handling thread cones according to work, age and employment duration.

This paper studies the relationship between some socio-professional characteristics of workers (e.g. age, actual work done, experience in the job, overall time on job market, height) carrying out thread-cone handling tasks and their musculoskeletal pain profiles. Interviews were carried out with foremen and workers, and task analysis was performed. Self-administered questionnaires on work-related pain were filled out by 114 machine operators and creelers in four carpet-manufacturing companies. Statistics on nine individual and 25 pain-symptom characteristics were compiled. For data treatment, two statistical methods complemented one another: the Factorial Analysis of Correspondence (FAC) and the Hierarchical Ascendant Classification (HAC). Four classes of workers showing large differences one to another regarding time of employment on the job market, age, seniority in the company, and job experience were portrayed. No remarkable differences were found between the classes in relation to the proportion of workers showing body pain symptoms; it is greater than 50% in all classes (12 months). Moreover, in all classes, for several workers, the first region of pain (out of three possible) was reported as one persisting over the weekend. The group of workers from 25 to 35 years of age appears to be the one most seriously affected by musculoskeletal pain.

Adult↗
PubMed1993

Children's self-regulated learning of movement sequences.

The purpose of this study was to determine whether developmental differences exist in childrens' use of self-regulatory strategies while learning supra-memory-span movement sequences. Grade 1 and Grade 4 children were asked to study two movement sequences long enough to be absolutely certain that they would be able to recall the entire sequences correctly. The older group displayed superior recall readiness in comparison to the younger group. Older children used a greater variety of strategies and also displayed significantly greater numbers of strategy orchestration patterns. In addition, Grade 4 children more frequently used overt encoding and self-checking strategies. Further, evidence suggests that Grade 4 children used language to encode movement components or to regulate their own learning more frequently than Grade 1 children.

Age Factors↗
PubMed1999

Individual differences, perceived task characteristics, and preferences for teaching and coaching.

One hundred ninety-two undergraduate physical education students participated in this study of the influence of individual differences, group, and task factors on respondents' preferences for teaching or coaching. The individual difference factors were gender, managerial potential (Gough, 1984), and sex role attributes (Spence & Helmreich, 1986). The group and task differences were measured by a specially developed scale that was factor analyzed to yield six factors: job status, job significance, job variety and control, job identity, ease of discipline, ease of motivation. Subgroup analyses showed that men preferred more to coach than women did, and women preferred more to teach than men did. Men and women perceived greater job variety in coaching and greater control in teaching. The genders did not differ in managerial motivation or in any of the other perceived characteristics of the teaching and coaching roles. Finally, preference for teaching or coaching was influenced by gender, perceived ease of motivating students and athletes, and perceived job variety. These results were discussed in relation to existing literature, and future research directions are identified.

Adult↗
PubMed2001

Scaling-up HIV/AIDS and TB home-based care: lessons from Zambia.

Home-based care coverage in Africa is currently very low and likely to reduce drastically in the near future. This paper investigates the low coverage of home-based care programmes in Africa and uses two home-based care projects in Zambia as case studies. The very limited involvement of governments in the provision of home-based care services appears to be one of the main reasons behind the low coverage of home-based care in Africa. Governments therefore should provide some form of basic home-based care services and/or strengthen support to other institutions providing home-based care. In order to facilitate governments' involvement in home-based care activities, an analysis of tasks performed by community nurses and volunteers is used to identify tasks that government, missionary or NGO employed nurses may be able to provide without, or with very limited, donor assistance. However, further research and development is needed to develop affordable, feasible and sustainable home care programmes that can be implemented by staff working in government, NGO and missionary health facilities. In addition, innovative strategies are required to establish effective partnerships between the NGO, missionary and government health facilities.

Community Health Nursing↗
PubMed1991

Gender verification in sport: the need for change?

Most of an estimated one in 504 sportswomen fail the gender verification test unjustly. Until clinical examination becomes acceptable, a new code of practice is proposed which avoids unfair disqualification.

Chromosome Aberrations↗
PubMed1976

SAM Complex Coordinator and Multidimensional Pursuit Test: annotated bibliographies.

A brief description of the SAM Complex Coordinator (Mashburn Apparatus) and the SAM Multidimensional Pursuit Test (MDP or MPT) and annotated bibliographies including 144 and 51 citations respectively are presented. All references are annotated as to subject matter within six categories; Factor Analytic-Task Taxonomy, Aircrew Selection-Classification, Learning Phenomena, Stress Effects, History and Development, General Reviews.

Aerospace Medicine↗
PubMed1999

[The cost effectiveness of echography biopsy].

Ecopsy is a postmortem technique which, by means of echography-guided puncture and/or aspiration obtains material for histological analysis. This study compared cost and time employed in 100 ecopsies and 100 classic necropsies and confirmed that cost of materials in ecopsy is 65% lower than that in necropsy. Physicians, necropsy technicians, laboratory technicians and secretary team personnel spent 33%, 54%, 19% and 32% less time than in necropsy. The clinical report of ecopsy was finished within nine days even with the brain study included.

Adult↗