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PubMed2001

Model TJ-IV computer-assisted vectorcardiogram analysis system.

During last 16 years we have successfully developed the computer-assisted vectorcardiogram analysis systems: model TJ-I, TJ-II, and TJ-III, but some technical problems remained unresolved, such as the recognition accuracy for vectorcardiograms, measurement of the parameters of complicated QRS waves, the ratio of T loop length to width, and the area of spatial vectors etc. A new system, model TJ-IV was designed to resolve these technical problems. The system was equipped with a 586 computer with a CPU of 120 MHz. Special new low-noise amplifier was employed and C language was used for programming. Three graph recognition techniques were used to enhance the accuracy of VCG recognition. 32 orthogonal electrocardiograms and vectorcardiograms were displayed and printed, and 566 parameters of vectorcardiograms were calculated. Our results with 150 cases showed that the system had high accuracy of graph recognition, and parameter calculation and the results were essentially consistent with those of manipulative methods. We were led to concluded when compared with TJ-III system, the new version has higher accuracy of processing and measurement for vectorcardiograms, is able to process more vectorcardiographic parameters, with higher processing speed.

Adult↗

PubMed1998

Visual search tasks: slowing of strategic and nonstrategic processes in the nonlexical domain.

Some investigators have argued that aging affects the slowing of processes in nonlexical tasks more than it does the slowing of processes in lexical tasks, but that within task domains, the slowing is identical. Other investigators have argued that even within nonlexical tasks there is differential slowing such that aging affects processing speed more in (nonlexical) coordinative tasks than it does in (nonlexical) sequential tasks. Perhaps, more finely still, there is a differential slowing in coordinative nonlexical tasks. Toward this end, latent models of general and process-specific slowing in coordinative nonlexical tasks were formulated for older adults. A visual search task was then used to test the two types of models. It was found that a latent model of process-specific slowing explained significantly more of the variability than a latent model of general slowing, indicating that there is a differential slowing of processes among coordinative tasks within the nonlexical domain. It was also discovered that the coordinative process most greatly affected was that of deciding to terminate the search when no target was present in the display, indicating together with other studies a possible difference in the slowing of strategic processes among both coordinative and sequential tasks within the nonlexical domain, but no difference in the slowing of nonstrategic processes.

Adult↗

PubMed2003

The interactive effects of alcohol and temazepam on P300 and reaction time.

The present research investigated the separate and interactive effects of the minor tranquilizer, temazepam, and a low dose of alcohol on the amplitude and latency of P300 and on reaction time. Twenty-four participants completed four drug treatments in a repeated measures design. The four drug treatments, organised as a fully repeated 2 x 2 design, included a placebo condition, an alcohol only condition, a temazepam only condition, and an alcohol and temazepam combined condition. Event-related potentials were recorded from midline sites Fz, Cz, and Pz within an oddball paradigm. The results indicated that temazepam, with or without the presence of alcohol, reduced P300 amplitude. Alcohol, on the other hand, with or without the presence of temazepam, affected processing speed and stimulus evaluation as indexed by reaction time and P300 latency. At the low dose levels used in this experiment alcohol and temazepam appear not to interact, which suggests that they affect different aspects of processing in the central nervous system.

Adolescent↗

PubMed2004

The impact of prenatal alcohol exposure on neurophysiological encoding of environmental events at six months.

BACKGROUND: Using methodologies from developmental studies on infant information-processing skills, early manifestations of later long-term neurocognitive effects of prenatal alcohol exposure can be explored by assessing primary cognitive processes, including attentional regulation and processing speed. METHODS: One hundred eighteen 6-month-old infants (18 high risk, 100 low risk) from a longitudinal study of moderate prenatal alcohol exposure and intrauterine growth retardation were presented with both auditory (400 and 1000 Hz pure tones) and visual stimuli (chromatic Caucasian faces) in an information-processing paradigm with cardiac response as the dependent variable. The first three habituation trials were analyzed to assess neurophysiological encoding of environmental events in infants categorized as high and low risk based on status of maternal drinking. Specific indexes of the cardiac response were used to assess the infant's (1). speed of initiating attention, (2). sustained attention, and (3). shifting attention after stimulus offset. RESULTS: Infants identified as high risk based on a cumulative risk index for prenatal alcohol exposure responded more slowly to stimuli and were rated as significantly higher in arousal level across the three trials but did not display differences in their sustained deceleration responses or responses to stimulus-offset. CONCLUSIONS: Less efficient neurophysiological encoding was observed among high-risk infants, suggesting that prenatal alcohol exposure may disrupt fundamental components of the attentional system responsible for regulating the body's responses to environmental events. Slower neurophysiological responses involved in encoding environmental stimuli and initiating attention and higher levels of behavioral arousal suggest that these infants may have had difficulties with regulating the interactions between arousal level and the attentional system needed to provide optimal efficiency in processing environmental events. These outcomes suggest that prenatal alcohol exposure results in specific impairments in early attentional regulation, which may influence subsequent cognitive development and behavioral outcomes dependent on these primary cognitive processes.

Acoustic Stimulation↗

PubMed2001

Correlation of atrophy measures on MRI with neuropsychological sequelae in children and adolescents with traumatic brain injury.

To examine the relationship between neuropsychological sequelae and atrophy parameters from magnetic resonance imaging (MRI) following paediatric moderate-to-severe traumatic brain injury (TBI), 19 head injured children and adolescents were studied at least 6 years after injury. Three-dimensional MRI scans were obtained. A semi-automatic computerized method was used to estimate ventricular volumes and the corpus callosum area. Tests of intellectual, memory, visuospatial, frontal lobe, and motor speed functioning were administered to all patients and to 19 matched normal control subjects. Patients' performance significantly differed from controls in general intellectual function, visual memory, visuospatial and frontal lobe tests. The corpus callosum area correlated strongly with several measures involving processing speed and visuospatial function. Ventricular enlargement was less related to neuropsychological outcome. In conclusion, quantitative measurement of the corpus callosum on MRI reflects neuropsychological outcome better than ventricular dilation in paediatric patients.

Adolescent↗

PubMed2001

Individual differences in performance on elementary cognitive tasks (ECTs): lawful vs. problematic parameters.

Over the past 2 decades, the cognitive-correlates approach has dominated investigations into the nature of intelligence. This research program relies on a number of processing speed parameters (apart from "average performance"). These measures include the slope, intercept, and intraindividual variability of both decision time and movement time. By correlating these measures with established markers of intelligence, researchers postulate theoretical models underlying these information-processing constructs. However, there is a lack of substantive evidence that these phenomena are as robust within the individual as has been proposed. The authors tested the properties of intraindividual parameters by asking participants (N = 179) to perform 10 elementary cognitive tasks (ECTs). Detailed analyses revealed that average performance parameters, extracted from these ECTs, behaved lawfully. However, up to 40% of participants failed to provide acceptable indices of intraindividual model fit. Similarly, intraindividual variability measures appeared less valid than previously suggested. The implications of these findings for cognitive and biological models of intelligence are discussed.

Adolescent↗

PubMed1986

Image processing--principles and its future applications in reconstructive and aesthetic plastic surgery.

Although the great importance of the visual aspect to medical science, and plastic surgery in particular, is beyond doubt, the utilization of image systems for transmission, storage, and processing of images is not at all widespread. The main reason for this phenomenon is that owing to the high complexity of imaging-related equipment, in comparison with other means such as audio equipment (telephone, tape recorders, and so on), more complicated systems are required, including wider broadcasting channels, much larger storage capacities, and higher processing speeds than are available now. Except for extensive research and development activities in the universities, research institutes, and military organizations, the large potential of the artificial visual aspect is not commonly utilized. In the future, efficient utilization of image processing capabilities in the service of plastic surgery will be achieved by the emerging capabilities for many complicated procedures. These include huge image data base processing, automatic detection of pathologic cases by enhancement of details and recognition of patterns, accurate measurements of the changes and distortions in the processed images, prediction of results to allow planning of treatment, simulation, and training on computerized cases. The new capabilities also include visual control of robotic arms for complicated operations, better audio-visual communication between faraway clinics and medical centers via sophisticated teleconferencing systems--which will save traveling expenses and time and will enable the updating of medical information--and many more applications that will be developed when the basic equipment becomes an integrated part of the clinics and plastic surgery departments. Future image processing will enhance the visual aspect in the plastic surgeon's work and will enable the doctor to expand his or her professional capabilities.

Automation↗

PubMed2006

Basic numerical skills in children with mathematics learning disabilities: a comparison of symbolic vs non-symbolic number magnitude processing.

Forty-five children with mathematics learning disabilities, with and without comorbid reading disabilities, were compared to 45 normally achieving peers in tasks assessing basic numerical skills. Children with mathematics disabilities were only impaired when comparing Arabic digits (i.e., symbolic number magnitude) but not when comparing collections (i.e., non-symbolic number magnitude). Moreover, they automatically processed number magnitude when comparing the physical size of Arabic digits in an Stroop paradigm adapted for processing speed differences. Finally, no evidence was found for differential patterns of performance between MD and MD/RD children in these tasks. These findings suggest that children with mathematics learning disabilities have difficulty in accessing number magnitude from symbols rather than in processing numerosity per se.

Analysis of Variance↗

PubMed1997

Examination of age-related deficits on the Wisconsin Card Sorting Test.

Adult age differences in Wisconsin Card Sorting Test (WCST) measures were examined before and after statistical control of age-related differences in measures of feedback usage, working memory, and perceptual-comparison speed. The proportion of age-related variance associated with a summary measure of WCST performance was greatly reduced after controlling for measures of feedback usage, working memory, and perceptual-comparison speed. Furthermore, the age-related variance associated with the feedback-usage measure was reduced after controlling for working memory and perceptual-comparison speed measures. These results are consistent with the idea that age-related performance differences in the WCST are partially mediated by adult age differences in feedback usage and that age differences in feedback usage are mediated by age differences in working memory, which are in turn-mediated by age-related reductions in processing speed, indexed by measures of perceptual-comparison speed.

Adolescent↗

PubMed1986

An automated technique for analysis of current transitions in multilevel single-channel recordings.

Detailed kinetic studies of ion channel gating are best carried out using the patch-clamp technique which permits the measurement of the ionic current through individual channels. Typical patch-clamp recordings show the current signal, in the form of a sequence of rectangular pulses (analogous to a random telegraph signal), riding on slow baseline drift, partially obscured by high-frequency noise and distorted by filtering. In order to analyze such recordings, we have developed a set of interactive Pascal programs based on a feature-detection algorithm capable of identifying current transitions in multiple-channel recordings in the presence of substantial levels of noise and drift. Software operation is largely automated but includes provisions for examination and correction of the output. The software was optimized and systematically evaluated using simulated data with variable amounts of noise and drift. Results indicate that satisfactory performance is obtained for signal-to-noise ratio as low as four even with uncommonly large baseline drift. Steady-state processing speeds varied from 1,000 to 4,000 samples per second depending on data complexity.

Automation↗

PubMed2003

Neuropsychological sequelae of exposure to welding fumes in a group of occupationally exposed men.

This study compares the neuropsychological function, emotional status, visual function, and illness prevalence of 76 former and current chemical industry welders primarily involved in steel welding, and exposed to welding fumes for an average of 24.9 years with that of 42 unexposed, non-welder controls. Health and occupational history questionnaires were administered, as were the neuropsychological tests included in the World Health Organization Neurobehavioral Core Test Battery, Luria Motor Test, and selected tests from the WAIS-III, and WMS-III. Emotional status tests included the BSI, POMS, BAI, and BDI, and vision tests included the Snellen near visual acuity, Lanthony d-15 color vision, Vistech Contrast Sensitivity, and Schirmer strips. While welders and controls performed similarly on tests of verbal skills, verbal retention, and auditory span, welders performed worse than controls on tests of verbal learning, working memory, cognitive flexibility, visuomotor processing speed, and motor efficiency. Welders had poorer color vision and emotional status, and increased prevalence of illnesses and psychiatric symptoms. The increased symptoms in welders were related to decreased scores on tasks measuring verbal learning, visuomotor abilities, visuospatial abilities, and information processing, and motor efficiency. Within the group of welders, the number of hours welding was negatively related to scores on verbal learning, auditory span, working memory, cognitive flexibility, and motor efficiency.

Adult↗

PubMed2005

A randomized crossover trial comparing three plateletpheresis machines.

BACKGROUND: The aim of the study was to compare three different apheresis machines with the same donors regarding the processing time required to obtain a 3.5 x 10(11) platelet (PLT) dose and acceptance by donors. STUDY DESIGN AND METHODS: A randomized crossover trial was performed to evaluate the differences between the Amicus Crescendo (Baxter Biotech Corp.), the MCS Plus (Haemonetics Corp.), and the Trima Accel (Gambro BCT). Donations from 51 donors were compared for time adjusted to obtain a standard 3.5 x 10(11) PLT dose (TSD3.5), efficiency, adverse reactions, yield, leukodepletion, machine accuracy, and donor preferences. Processing times were measured by chronometer. The same vein access was used during all three processes in each donor. In the statistical analysis, to take into account the nonindependence of several measurements from the same donor, generalized estimating equations were used with an autoregressive correlation matrix. RESULTS: The Accel produced a TSD3.5 (mean +/- SEM) of 47.9 +/- 1.0 min; the Amicus, 60.3 +/- 1.0 min; and the MCS Plus, 66.7 +/- 1.0 (p < 0.0001). The Amicus presented the greatest efficiency (87.5%; p < 0.0028). The MCS Plus demonstrated the highest capacity for leukodepletion (p < 0.0002) despite one process presenting more than 1 x 10(6) white blood cells per unit. The MCS Plus also measured the processing time with the greatest accuracy. No severe adverse effects were observed. The donors preferred the Accel (61%) followed by the Amicus (35%) and the MCS Plus (4%; p < 0.0001) and the processing speed was the most highly valued measure (55%). CONCLUSIONS: The Accel is the fastest and, because of this advantage, the machine preferred by donors. The Amicus was the most efficient and the MCS Plus was the only one not to underestimate the processing time.

Cross-Over Studies↗

PubMed2005

Differential impairment in recognition of emotion across different media in people with severe traumatic brain injury.

Recent evidence suggests that there may be dissociable systems for recognizing emotional expressions from different media including audio and visual channels, and still versus moving displays. In this study, 34 adults with severe traumatic brain injuries (TBI) and 28 adults without brain injuries were assessed for their capacity to recognize emotional expressions from dynamic audiovisual displays, conversational tone alone, moving facial displays, and still photographs. The TBI group were significantly impaired in their interpretation of both audio and audiovisual displays. In addition, eight of the 34 were significantly impaired in their capacity to recognize still facial expressions. In contrast, only one individual was impaired in the recognition of moving visual displays. Information processing speed was not found to play a significant role in producing problems with dynamic emotional expression. Instead the results suggest that visual moving displays may enlist different brain systems to those engaged with still displays, for example, the parietal cortices. Problems with the processing of affective prosody, while present, were not clearly related to other emotion processing problems. While this may attest to the independence of the auditory affective system, it may also reflect problems with the dual demands of listening to conversational meaning and affective tone.

Acoustic Stimulation↗

PubMed2002

Linguistic outcomes following traumatic brain injury in children.

Recent studies of outcome after traumatic brain injury (TBI) emphasize the adverse effect of diffuse brain injury on linguistic development. This article reviews studies of lexical development, discourse processes, and reading in children and adolescents with TBI. The child's developmental level at the time of injury is related to the pattern of deficits. Young children who sustain severe TBI are particularly vulnerable to linguistic deficits at both lexical and discourse levels. TBI in older children and adolescents preferentially disrupts higher-order discourse functions. The contribution of deficits in fundamental processes, such as working memory and processing speed, to linguistic outcomes requires further investigation.

Adolescent↗

PubMed1998

Working memory deficits of reading disabled children.

Aims of the study were to investigate the specificity of reading disabled childrens deficits in working memory capacity and to pursue whether their deficits could be accounted for by deficient processing or impairments in verbal short-term storage capacity. A group of 10-year-old reading disabled children was compared with two groups of normal reading children, matched for chronological age and reading age, respectively. Measures for working memory capacity, short-term capacity and processing speed related to the language and to the numerical domain were administered. Results indicated that reading disabled children performed worse on all measures of working memory capacity, irrespective of the domain which these measures reflected. Their poorer performance could neither be explained by inefficient processing nor to their deficits in verbal short-term storage capacity. Reading disabled children seem to have a general lack of capacity for the concurrent processing and storage of verbal information.

Child↗

PubMed2002

Steady-state visually evoked potential topography during processing of emotional valence in healthy subjects.

The International Affective Picture System (IAPS) is increasingly used in brain imaging studies to examine emotional processes. This task allows valence and arousal content to be systematically investigated; however, previous studies have generally failed to select images that vary in one dimension as well as hold constant the variability on the other dimension. In addition, no studies have investigated the temporal structure associated with the conscious, ongoing processing of emotional stimuli following systematic selection of IAPS images. The aim of the present study was therefore to use steady-state probe topography (SSPT) to examine the steady-state visually evoked potentials (SSVEPs) associated with the processing of pleasant and unpleasant images low in arousal content. Seventy-five IAPS images, categorized as unpleasant, neutral, or pleasant, were presented to 16 healthy subjects while brain activity was recorded from 64 scalp sites. Analysis subtracted the activity associated with the presentation of neutral images from the activity associated with the presentation of pleasant as well as unpleasant images. Results demonstrate that both pleasant and unpleasant valence is associated with transient, widespread, and bilateral frontal SSVEP latency reductions. Unpleasant images were also associated with a transient bilateral anterior frontal amplitude decrease. Latency reductions are interpreted as increases in neural information processing speed, while amplitude reductions are interpreted in the current paper as analogous to an event-related desynchronisation commonly associated with the alpha bandwidth. These key findings support previous literature in terms of there being substantial overlap in frontal neural circuitry when the brain processes pleasant and unpleasant valence relative to neutral valence.

Adult↗

PubMed2006

Testosterone loss and estradiol administration modify memory in men.

PURPOSE: Little is known about the effect of androgen deprivation therapy on the brain despite the fact that sex steroid receptors are abundant in cortical brain regions that mediate memory and other cognitive functions. We characterized the impact of androgen deprivation and of subsequent estradiol therapy on the long-term and working memory of patients with prostate cancer. MATERIALS AND METHODS: Long-term memory (immediate and delayed paragraph recall tests), working memory (SOP and Trails tests) and Profile of Mood States were assessed at baseline and 4 weeks later in 18 patients with androgen independent prostate cancer beginning second line hormonal therapy with transdermal estradiol 0.6 mg/24 hours. The same assessments were performed in 2 age matched control groups of 18 patients with prostate cancer undergoing androgen deprivation continuing on hormonal therapy and 17 community dwelling healthy men. RESULTS: Immediate and delayed verbal memory were significantly worse in patients with prostate cancer on androgen deprivation than in age matched healthy controls. In addition, men with prostate cancer took more time to complete the Trails A task, indicating slower processing speed, but did not differ significantly from healthy controls in working memory tasks. In individual repeated measures analyses, verbal memory performance improved with estradiol therapy but did not change in the 2 control groups. CONCLUSIONS: Sex steroid loss and replacement have effects on specific cognitive processes in older men. Furthermore, estrogen has the potential to reverse the neurotoxic effects on memory performance caused by androgen deprivation.

Affect↗

PubMed2006

Stress-related cognitive interference predicts cognitive function in old age.

Both subjective distress and cognitive interference have been proposed as mechanisms underlying the negative effects of stress on cognition. Studies of aging have shown that distress is associated with lower cognitive performance, but none have examined the effects of cognitive interference. One hundred eleven older adults (M-sub(age)=80) completed measures of working memory, processing speed, and episodic memory as well as self-report measures of subjective distress and cognitive interference. Cognitive interference was strongly associated with poorer performance on all 3 cognitive constructs, whereas distress was only modestly associated with lower working memory. The results suggest that cognitive process related to stress is an important predictor of cognitive function in advanced age.

Aged↗