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At least 1,153 records · Page 64Linked to original sources

PubMed2003

Contrasting effects of sensory limits and capacity limits in visual selective attention.

The effects of perceptual load and those of target-stimulus degradation on distractor processing were contrasted. Targets either had to be found among several nontargets (high perceptual load) or were presented alone and were intact (low perceptual load), had reduced size and contrast (Experiment 1), had reduced duration and were followed by a mask (Experiment 2), or had reduced visual acuity owing to position eccentricity (Experiment 3) in the degraded low-load condition. The results showed that both high perceptual load and target degradation increased general task difficulty, as is reflected by overall reaction times and accuracy. However, whereas high perceptual load reduced response-competition effects of irrelevant distractors, target degradation increased distractor effects. These results support the hypothesis that distractor processing depends on the extent to which high perceptual load exhausts attention in relevant processing and provide a dissociation between perceptual load and general task difficulty and processing speed.

Attention↗

PubMed2001

Distinguishing short-term memory from working memory.

The aim of the present research was to determine whether short-term memory and working memory could be distinguished. In two studies, 7- to 13-year-olds (N = 155, N = 132) were administered tasks thought to assess short-term memory as well as tasks thought to assess working memory. Both exploratory and confirmatory factor analyses distinguished short-term memory tasks from working memory tasks. In addition, performance on working memory tasks was related to word decoding skill but performance on short-term memory tasks was not. Finally, performance on both short-term memory and working memory tasks were associated with age-related increases in processing speed. Results are discussed in relation to models of short-term and working memory.

Adolescent↗

PubMed1999

Individual and developmental differences in working memory across the life span.

The effects of secondary tasks on verbal and spatial working memory were examined in multiple child, young adult, and older adult samples. Although memory span increased with age in the child samples and decreased with age in the adult samples, there was little evidence of systematic change in the magnitude of interference effects. Surprisingly, individuals who had larger memory spans when there was no secondary task showed greater interference effects than their age-mates. These findings are inconsistent with the hypothesis that age and individual differences in working memory are due to differences in the ability to inhibit irrelevant information, at least as this hypothesis is currently formulated. Moreover, our results suggest that different mechanisms underlie developmental and individual differences in susceptibility to interference across the life span. A model is proposed in which memory span and processing speed both increase with development but are relatively independent abilities within age groups.

Adult↗

PubMed1998

Estimates of driving abilities and skills in different conditions.

OBJECTIVES: This research was a preliminary effort to determine whether various driving situations seemed to require different driving skills and abilities and to identify the relative demands of specific physical, perceptual, cognitive, behavioral, and operational skills and abilities in different driving situations. METHOD: Experienced driver evaluators and trainers estimated the magnitude of driving abilities and skills for different photographed driving situations. Pictures of driving scenarios were counterbalanced for road type, traffic condition, and weather condition. RESULTS: A multifactorial analysis of variance of the total score for each scenario revealed significant main effects for road type and traffic condition but not for weather condition. Highway and city driving were rated as significantly more demanding overall than residential driving, but no difference was found between city and highway driving. Estimates of the overall demands for driving in heavy traffic were significantly greater than in light traffic. However, driving in inclement weather was not regarded as significantly more demanding than driving in sunny weather. Additionally, significant interaction effects were found for road type by weather condition and traffic by weather condition but not for road type by traffic condition. Through multivariate methods to evaluate the significance of individual abilities and skills across conditions, significant main and interactive effects were found for road type, traffic condition, and weather condition. Post hoc analyses showed the impact of these effects on such abilities and skills as scanning, attention and concentration, information-processing speed, and others. CONCLUSION: Evaluators' quantified estimates of driving demands showed driving as a complex task that (a) requires high levels of abilities and skills in all situations; (b) demands greater abilities in some situations than in others; and (c) involves different kinds and various degrees of abilities and skills, depending on the demand characteristics of the situation.

Adult↗

PubMedDate not supplied

Use of the UFOV to evaluate and retrain visual attention skills in clients with stroke: a pilot study.

OBJECTIVE: The objective of this pilot study was to examine the use of a visual attention analyzer in the evaluation and retraining of useful field of view in clients with stroke. METHOD: Fifty-two clients with stroke referred to a driving evaluation service were evaluated with a visual attention analyzer referred to as the UFOV. The UFOV assesses three aspects of visual attention: processing speed, divided attention, and selective attention. Seven participants were retested to determine the test-retest reliability of the UFOV. Six participated in the development of a training protocol and in a 20-session visual attention retraining program. RESULTS: UFOV scores indicated substantial reduction in visual attention in clients after stroke, with older participants performing the most poorly. Test-retest reliability was moderate (ICC = .70). Mean UFOV scores improved significantly after retraining. CONCLUSION: Although UFOV scores indicated poor visual attention skills in clients with stroke, preliminary information suggests that UFOV scores significantly improve with training.

Adult↗

PubMed2004

Time perception depends on accurate clock mechanisms as well as unimpaired attention and memory processes.

We report a series of studies aimed at characterizing the relationships between duration judgments and slowing down of the internal clock, attention and memory deficits. Different groups of participants (elderly people, patients with Parkinson's disease, patients with severe traumatic brain injury, and patients with temporal lobe lesions) performed a duration reproduction task and a duration production task in two conditions: a control counting condition and a concurrent reading condition. Participants were also administered reaction time tasks, tapping tasks, and a battery of attention and memory tests. The results allow us to characterize the relationships between cognitive deficits and impaired duration reproductions and productions in each group. Moreover, results as a whole clarify the respective weight of processing speed, attention and memory in both tasks, and allow better insight into the theoretical models of psychological time.

Adolescent↗

PubMed2006

Reference values for performance on the Automated Neuropsychological Assessment Metrics V3.0 in an active duty military sample.

The Automated Neuropsychological Assessment Metrics (ANAM) is a computerized measure of processing speed, cognitive efficiency, and memory. This study describes performance and psychometric properties of ANAM in an active duty, healthy military sample (N = 2,371) composed primarily of young (18-46 years) adult males. Rarely have neuropsychological reference values for use with individuals in the military been derived from a large, active duty military population, and this is the first computerized neuropsychological test battery with military-specific reference values. Although these results do not provide demographically corrected, formal normative data, they provide reference points for neuropsychologists and other health care providers who are using ANAM data in research or clinical settings, with patients of comparable demographics to the present sample.

Adolescent↗

PubMed1992

Special report on reimbursement. Medicare program abandons 1986 malpractice rule.

Hospitals with claims "properly pending" before fiscal intermediaries or in the courts need do nothing in order to obtain corrected reimbursement for fiscal years so pending. However, to speed processing of corrected reimbursements for fiscal years pending in appeals before the PRRB, hospitals should request that the Board determine its jurisdiction and remand to the fiscal intermediary for payment as soon as possible. It will be helpful to include with any such request a copy of the notice of program reimbursement and the original appeal letter for each fiscal year under appeal. Despite the fact that HCFA Ruling 91-1 effectively concedes that HCFA has applied an invalid regulation to all fiscal years since May 1, 1986, HCFA counsel have stated that HCFA will not permit reopening of closed cost reports to correct the inappropriate apportionment of malpractice insurance costs. Nevertheless, hospitals that do not presently have a claim or appeal pending have several options. Under the Provider Reimbursement Manual, HIM-15, sections 2930-2931, fiscal intermediaries are required to reopen cost reports filed within the three-year reopening period to correct errors. Accordingly, should a fiscal intermediary deny a provider's reopening request, the provider should seriously consider taking an appeal to the PRRB. The PRRB's jurisdiction to review fiscal intermediary denials of requests to reopen cost reports was affirmed by the United States Court of Appeals for the Ninth Circuit, see State of Oregon v. Bowen, 854 F.2d 346 (9th Cir. 1988), a decision that is controlling in California, Oregon, Washington, Nevada, Arizona, Montana, Idaho, Hawaii, Alaska, Guam, and the Northern Mariana Islands.(ABSTRACT TRUNCATED AT 250 WORDS)

Cost Allocation↗

PubMed1999

Cognitive effects of Lyme disease in children: a 4 year followup study.

OBJECTIVE: To measure cognitive effects of Lyme disease (LD) in a pediatric population 4 years after disease onset. METHODS: Prospective, blinded, multivariable controlled study of cognitive skills in children who have been treated for LD. The setting was a children's hospital in an area endemic for LD. Twenty-five children with strictly defined LD were compared with 17 control children (6 disease-control and 11 sibling-control). OUTCOME MEASURES: An extensive set of neuropsychological measures was administered. These included assessment of the cognitive areas of IQ, information processing speed, fine-motor dexterity, novel problem solving and executive functioning, short term and intermediate memory, and acquisition of new learning. Parents' ratings were also obtained concerning disease impact upon everyday activities. RESULTS: Seventeen of the 18 neuropsychological test measures showed the LD and control groups similar at time of 4 year followup. There were no differences between the groups regarding parents' impressions of disease impact. CONCLUSION: In contrast to studies of adults with LD, the results of longterm followup of the pediatric population continue to strongly support the finding that children treated appropriately for LD have an excellent prognosis for normal cognitive functioning.

Analysis of Variance↗

PubMedDate not supplied

Validation of a microwave sterilizer for injection ampules.

A program for validating the microwave sterilizer, which is a new type of sterilizer, was established and implemented. This program includes the following tests specific to microwave sterilizers: the internal pressure strength of ampules, the acceptable range of sterilizing temperature, performance and calibration of the infrared thermometer and the plane blackbody, maintaining of sterilizing temperature, the processing speed (sterilizing time), the unacceptable ampules selection mechanism, microwave leaks, and a microbiological challenge test of the ampule head space using a biological indicator. Injectable preparations of mecobalamin and diprophylline were used as models for validation of the microwave sterilizer. The bioburden approach was used for injectable mecobalamin preparation, and the over-kill approach was used for injectable diprophylline preparation. The basis for practical use of this microwave sterilizer has been confirmed by the establishment and implementation of this validation program.

Drug Packaging↗

PubMed2000

[Cognitive and emotional disorders in multiple sclerosis. Can a management strategy be envisioned?].

There is a lack of precise data concerning the natural history of cognitive disorders in multiple sclerosis (MS), but recent neuropsychological studies have demonstrated that the incidence of such disorders in MS appears to be frequent (40-65% of cases), and have shown in particular that recent memory, conceptual reasoning, attention, executive functions, visuospatial perception and information processing speed are negatively affected. In contrast, language functions, general intelligence and implicit memory appear to be relatively well preserved. Although the presence and the degree of cognitive disorders does not seem to be directly linked to disease duration or to the extent of physical disability, the relationship between cognitive decline and brain lesions detected by magnetic resonance imaging (MRI) is still a subject of discussion. The prevalence of emotional and affective disorders is difficult to estimate. Their frequency has only rarely been investigated, and the lack of data on the natural history of these disorders and those factors which they have in common (the psychosocial consequences of this chronic and disabling disease, cognitive impairment, and brain lesions) further complicate the determination of treatment strategy. The adoption of appropriate strategies could limit the negative impact of this disease on the social functioning of MS patients.

Cognition Disorders↗

PubMedDate not supplied

The effects of nicotine on Parkinson's disease.

Post-mortem studies have demonstrated a substantial loss of nicotinic receptors in Parkinson's disease (PD), which may be at least partially responsible for some of the cognitive, motoric, and behavioral deficits seen in this disorder. Epidemiologic studies have suggested that cigarette smoking is a strong negative risk factor for the development of PD. We have previously shown that blockade of central nicotinic receptors produces cognitive impairment in areas of new learning, short-term memory, and psychomotor slowing with increasing dose sensitivity with age and disease. Studies of acute stimulation of nicotinic receptors in Alzheimer's disease with nicotine and the novel agonist ABT-418 in our laboratory and others have shown improvements in several measures of cognitive function. Prior studies of the effects of nicotine in PD have suggested some improvements in clinical symptomatology. We have begun quantitative studies of both acute and chronic nicotine in PD to assess both cognitive and motor effects. Fifteen (15) nondemented subjects (age 66 +/- 5.3; M/F = 11/4) with early to moderate PD (mean Hoehn-Yahr stage = 1.77; MMSE = 28.6) received a dose-ranging study of intravenous nicotine up to 1.25 microg/kg/min, followed by chronic administration of nicotine by transdermal patch with doses ranging up to 14 mg per day for 2 weeks. Testing occurred both during drug administration and up to 2 months after drug cessation to look for prolonged effects. Preliminary analysis shows improvements after acute nicotine in several areas of cognitive performance, particularly measures such as reaction time, central processing speed, and decreased tracking error. Improvements in attention and semantic retrieval were not seen. After chronic nicotine, improvements were seen in several motor measures suggesting improved extrapyramidal functioning. This appeared to be sustained for up to 1 month after drug. The treatment was well tolerated. Nicotinic stimulation may have promise for improving both cognitive and motor aspects of Parkinson's disease.

Aged↗

PubMed2000

Total simulation of operator team behavior in emergencies at nuclear power plants.

In a large and complex system (i.e., a space aeronautics and nuclear power plant) it would be valuable to conduct operator training and support to demonstrate standard operators' behavior in coping with an anomaly caused by multiple malfunctions in which procedures would not have been stipulated previously. A system simulating operator team behavior including individual operator's cognitive behavior, his operations and physical behavior, and even verbal communication among team members, has been developed for a typical commercial nuclear power plant. This simulation model is not a scenario-based system but a complete knowledge-based system, based on the mental model that was envisaged by detailed analyses of experimental results obtained in the full-scope plant simulator. This mental model is composed of a set of knowledge bases and rules able to generate both diagnosis and prognosis depending on the observed situation even for multiple malfunctions. Simulation results of operator team behavior and plant dynamics were compared with corresponding experiments in several anomalies of multiple malfunctions. The comparison showed a reasonable agreement, so the simulation conditions were varied on cognitive task processing speed of individual operators, on team role sharing scheme, and on human machine interface (1st generation to 2nd generation control panel) to assess the sensitivity of this simulation model. Finally, it was shown that this simulation model has applications for the use of training standards and computer aided operator support systems.

Computer Simulation↗

PubMed2000

Replication of the factor structure of the Wechsler Adult Intelligence Scale--Third Edition with a Canadian sample.

Exploratory and confirmatory factor analyses of the subtests of the Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997b) were conducted on a stratified sample of Canadian adults (n = 718). As was previously demonstrated for the children's version of this scale, the factor model of the American standardization sample was replicated across this Canadian national sample. Results of the factor analyses confirmed the presence of the 4 WAIS-III factors: Verbal Comprehension, Perceptual Organization, Working Memory, and Processing Speed.

Adolescent↗

PubMedDate not supplied

[Factorial structure of the executive functions in young university students].

INTRODUCTION: Several studies have proposed a multiple dimensional theoretical model for executive function. OBJECTIVE: To identify the factor structure of the executive function in a sample of young university students of different modalities of learning in their careers. METHODS: 100 participants of both sexes, age 16 to-21-year old and normal Full Scale IQ were selected in a randomized and representative approach from private universities of Medellin Colombia. They were student of verbal, visuospatial and mathematical careers. A executive function assessment battery were applied, which included: Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT) A and B, verbal fluency test (FAS) by phonologic and semantic guides, and Stroop test. RESULTS: A structure of four factor was found, which explained 74.9% of variance. Factors were: 1. Organization and flexibility, which explained 26.6% of variance; 2. Processing speed, 19.7%; 3. Inhibitory control, 15.1%; and 4. Verbal fluency 13.4%. CONCLUSION: A multiple factor structure of the executive function in young university students was demonstrated.

Adolescent↗

PubMed2001

Influences on the efficiency of prospective memory in younger and older adults.

The influence of 4 factors on age-related declines in prospective memory (PM) was considered in 2 experiments. The results of the experiments reveal that age-related differences in PM were not moderated by the degree of match between the nature of processing required in the ongoing activity and the defining features of the PM cue. Age-related differences in the accuracy of PM responses were primarily attributable to an increase in the number of omission errors committed by older adults. Age-related differences in PM were somewhat independent of the ability to recall the PM cues and intentions following task performance and were mediated by the cognitive resources of processing speed, inhibitory control, and working memory.

Adult↗

PubMed2001

Sensitivity and specificity of WAIS-III/WMS-III demographically corrected factor scores in neuropsychological assessment.

This study explored the neurodiagnostic utility of 6 factor scores identified by recent exploratory and confirmatory factor analyses of the WAIS-III and WMS-III: Verbal Comprehension, Perceptual Organization, Processing Speed, Working Memory, Auditory Memory and Visual Memory. Factor scores were corrected for age. education, sex and ethnicity to minimize their influences on diagnostic accuracy. Cut-offs at 1, 1.5 and 2 standard deviations (SDs) below the standardization sample mean were applied to data from the overlapping test normative samples (N = 1073) and 6 clinical samples described in the WAIS-III/WMS-III Technical Manual (N = 126). The analyses suggest that a I SD cut-off yields the most balanced levels of sensitivity and specificity; more strict (1.5 or 2 SD) cut-offs generally result in trading modest gains in specificity for larger losses in sensitivity. Finally, using combinations of WAIS-III/WMS-III factors together as test batteries, we explored the sensitivity and specificity implications of varying diagnostic decision rules (e.g.,1 vs. 2 impaired factors = "impairment"). For most of the disorders considered here, even a small (e.g., 3 factor) WAIS-III/WMS-III battery provides quite good overall diagnostic accuracy.

Adult↗

PubMed2002

[Language abnormalities in patients with multiple sclerosis].

BACKGROUND: Patients suffering from multiple sclerosis (MS) have a high frequency of cognitive deficits. Research has demonstrated impairments in memory, attention, information-processing speed, and executive functions. Although it has been traditionally held that language function is commonly preserved in MS, some studies have demonstrated language impairment in these patients, particularly in tasks of naming and word-generation. OBJECTIVES: The aim of the study was to examine language functioning in MS, with particular interest in naming ability and verbal fluency. MATERIAL AND METHODS: Thirty patients with MS, and 30 neurologically intact normal controls, matched for age and educational level were evaluated. As part of a wider neuropsychological evaluation, all subjects were administered the Boston Naming Tests. To compare performances, a comprehensive classification of error types was devised. RESULTS: MS patients showed significantly lower performance on both linguistic measures than the control subjects. On the Boston Naming Test, MS patients obtained significant lower scores than controls, with a high rate of semantic errors. Additionally, they tended to show an also high number of visuoperceptual errors. Low scores on naming task correlated with low performance on verbal fluency. CONCLUSIONS: This study reveals that language function can be impaired in MS, and that naming difficulties are a frequent finding. This naming deficit seems to have a double origin, stemming from disruption at the levels of the perceptual and/or the semantic systems.

Adult↗