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At least 1,495 records · Page 83Linked to original sources
PubMed2026

Game changer? Cognitive-motor effects of VR exergaming compared to video-based training.

BACKGROUND/OBJECTIVE: Virtual reality (VR) exergaming enhances several cognitive domains through multisensory engagement. Acute cognitive benefits of VR are established, but evidence for direct comparisons with non-immersive controls is limited. This study aimed to determine whether VR exercise provides additional cognitive and cognitive-motor benefits beyond a matched non-immersive active stick-fight video (SFV) intervention, and whether effects persist after training. METHODS: In this randomized quasi-experimental study, N&#x2009;=&#x2009;55 healthy adults (VR: n&#x2009;=&#x2009;30; SFV: n&#x2009;=&#x2009;25; 25.5&#x2009;&#xb1;&#x2009;7.1&#x2009;years; 41.8% female) completed an 8-week program (2&#x2009;&#xd7;&#x2009;30&#x2009;min/week), of VR or SFV matched in movement patterns, frequency, intensity and duration. Measurements included reaction time (RT), Stroop Test (versions 1-3), Letter Cancellation Test (LCT), Trail Making Test (TMT), Trail Walking Test (TWT) and Fitts task (difficulty level 1-4). Data were analyzed using mixed-design ANOVAs. RESULTS: Improvements were observed in Stroop reading (F(1,53) = 14.84, p < .001, &#x3b7;2 = 0.219), Stroop inhibition (F(1,53) = 10.99, p = .002, &#x3b7;2 = 0.172), and LCT (F(1,53) = 4.57, p = .037, &#x3b7;2 = 0.079). A time&#x2009;&#xd7;&#x2009;group interaction was found for TMT (F(1,53) = 6.55, p = .031, &#x3b7;2 = 0.110), indicating greater changes following VR training. Both groups improved cognitive-motor performance (TWT: F(1,25) = 55.32, p < .001, &#x3b7;2 = 0.689; Fitts3: F(1,53) = 44.97, p < .001, &#x3b7;2 = 0.459), with greater gains for VR in Fitts3 (p = .006). CONCLUSION(S): Eight weeks of VR and SFV enhanced cognitive and cognitive-motor performance. VR provided domain-specific advantages in executive function, but these effects were not uniformly persistent. SFV sustained more improvements in real-world-relevant cognitive-motor tasks.

Humans↗
PubMed2005

High-throughput metal susceptibility testing of microbial biofilms.

BACKGROUND: Microbial biofilms exist all over the natural world, a distribution that is paralleled by metal cations and oxyanions. Despite this reality, very few studies have examined how biofilms withstand exposure to these toxic compounds. This article describes a batch culture technique for biofilm and planktonic cell metal susceptibility testing using the MBEC assay. This device is compatible with standard 96-well microtiter plate technology. As part of this method, a two part, metal specific neutralization protocol is summarized. This procedure minimizes residual biological toxicity arising from the carry-over of metals from challenge to recovery media. Neutralization consists of treating cultures with a chemical compound known to react with or to chelate the metal. Treated cultures are plated onto rich agar to allow metal complexes to diffuse into the recovery medium while bacteria remain on top to recover. Two difficulties associated with metal susceptibility testing were the focus of two applications of this technique. First, assays were calibrated to allow comparisons of the susceptibility of different organisms to metals. Second, the effects of exposure time and growth medium composition on the susceptibility of E. coli JM109 biofilms to metals were investigated. RESULTS: This high-throughput method generated 96-statistically equivalent biofilms in a single device and thus allowed for comparative and combinatorial experiments of media, microbial strains, exposure times and metals. By adjusting growth conditions, it was possible to examine biofilms of different microorganisms that had similar cell densities. In one example, Pseudomonas aeruginosa ATCC 27853 was up to 80 times more resistant to heavy metalloid oxyanions than Escherichia coli TG1. Further, biofilms were up to 133 times more tolerant to tellurite (TeO3(2-)) than corresponding planktonic cultures. Regardless of the growth medium, the tolerance of biofilm and planktonic cell E. coli JM109 to metals was time-dependent. CONCLUSION: This method results in accurate, easily reproducible comparisons between the susceptibility of planktonic cells and biofilms to metals. Further, it was possible to make direct comparisons of the ability of different microbial strains to withstand metal toxicity. The data presented here also indicate that exposure time is an important variable in metal susceptibility testing of bacteria.

Biofilms↗
PubMed2005

Answering cluster investigation requests: the value of simple simulations and statistical tools.

Cluster investigations remain an important public health issue as the number of reported clusters and public concern increase. This study shows how statistical considerations and a simulation tool may be helpful in providing communities with proper answers to the questions usually raised in such situations: How surprising is an observed childhood cancer excess? What could be learned from a statistical test? What could be learned from a case-control study? Using real demographic and incidence-rate data together with simulations based on the hypothesis that incidence rates are homogeneous, the probabilities of observing given situations were estimated. A number of real situations have been used as examples. The results of the simulation study showed, in detail, that no reliable information on the reality of an observed excess could be obtained a posteriori from a statistical test. A cluster of the same size may or may not be surprising, depending on the spatial area and time window to which the cases are related (i.e., the expected number of cases), and depending on the size of the referential territory to which this area is associated. The lack of power of a case-control study if no particular unusual exposure is present is also addressed. The approach described in this paper can easily be reproduced and adapted to many situations. It may be of assistance to health departments conducting cluster investigations and communicating with the public.

Adolescent↗
PubMed2001

Repeated exposure of flight phobics to flights in virtual reality.

The present study examined the effects of repeated exposure of flight phobics to flights in virtual reality (VR). Flight phobics were randomly assigned either to complete one VR test flight followed by four VR exposure flights (VR group; N=15) in one lengthy session or to complete one VR test flight followed by a lengthy relaxation training session (relaxation group; N=15). All participants completed a second VR test flight at the end of the session. Fear reports and physiological fear reactions (heart rate, skin conductance level) during VR exposures were registered, and fear of flying was assessed psychometrically from 3 weeks before to 3 months after exposure. Exposure to VR flights elicited subjective and physiological fear responses in flight phobics, and these responses attenuated within and across VR flights. Fear reduction associated with repeated VR exposure was greater than fear reduction caused by relaxation training. Fear of flying improved in both treatment groups, but several outcome measures indicated greater effects in the VR treated group than in the relaxation group. These findings indicate that exposure in virtual reality may offer a new and promising approach for the treatment of fear of flying.

Adaptation, Psychological↗
PubMed2005

The use of probrain natriuretic peptide in pleural fluid for the diagnosis of pleural effusions resulting from heart failure.

PURPOSE OF REVIEW: Natriuretic peptides are secreted by the myocardium in response to mechanical stretch and have been proposed as a possible test for assisting the diagnosis of heart failure. This article reviews the rationale for measuring N terminal probrain natriuretic peptide in pleural fluid to identify heart failure as the cause of a pleural effusion. RECENT FINDINGS: Rapid and accurate testing of natriuretic peptides as biomarkers for heart failure is now a clinical reality. In patients presenting with dyspnea, heart failure is usually absent at blood brain natriuretic peptide levels less than 100 pg/mL, possible from 100 to 500 pg/mL, and probable at levels greater than 500 pg/mL. In evaluating natriuretic peptide assays, one needs to consider carefully laboratory and biologic variation, including gender, sex, obesity, renal function, and the assay used. Potential future applications of natriuretic peptide testing include the differential diagnosis of pleural effusion. A recent study has shown good diagnostic characteristics in cardiac pleural effusions, with likelihood ratios of 13 and a diagnostic accuracy of more than 90% for pleural fluid N terminal probrain natriuretic peptide levels > or =1500 pg/mL. Specifically, N terminal probrain natriuretic peptide pleural levels correctly categorized most cardiac effusions misclassified as exudates by standard criteria, and discriminated between cardiac and hepatic transudates. SUMMARY: Pleural fluid N terminal probrain natriuretic peptide may help accurately differentiate cardiac from noncardiac conditions in patients presenting with pleural effusion.

Heart Failure↗
PubMed2003

Experimental design and sample size determination for testing synergism in drug combination studies based on uniform measures.

In anticancer drug development, the combined use of two drugs is an important strategy to achieve greater therapeutic success. Often combination studies are performed in animal (mostly mice) models before clinical trials are conducted. These experiments on mice are costly, especially with combination studies. However, experimental designs and sample size derivations for the joint action of drugs are not currently available except for a few cases where strong model assumptions are made. For example, Abdelbasit and Plackett proposed an optimal design assuming that the dose-response relationship follows some specified linear models. Tallarida et al. derived a design by fixing the mixture ratio and used a t-test to detect the simple similar action. The issue is that in reality we usually do not have enough information on the joint action of the two compounds before experiment and to understand their joint action is exactly our study goal. In this paper, we first propose a novel non-parametric model that does not impose such strong assumptions on the joint action. We then propose an experimental design for the joint action using uniform measure in this non-parametric model. This design is optimal in the sense that it reduces the variability in modelling synergy while allocating the doses to minimize the number of experimental units and to extract maximum information on the joint action of the compounds. Based on this design, we propose a robust F-test to detect departures from the simple similar action of two compounds and a method to determine sample sizes that are economically feasible. We illustrate the method with a study of the joint action of two new anticancer agents: temozolomide and irinotecan.

Animals↗
PubMed1990

The impact and use of written leaflets as a counselling alternative in mass antenatal HIV screening.

Pre-test counselling has been seen as a pre-requisite for HIV screening. As HIV moves into the heterosexual community, the role of HIV screening in ante-natal care has increased. As vertical transmission is the major contributor to perinatal infection HIV screening of pregnant women has become a reality. The pregnant population comprises large numbers, the practical difficulties of routine pre-test counselling and the informational demand from pregnant women themselves has necessitated the provision of ante-natal leaflets about HIV infection and AIDS. A survey of 24 London hospitals revealed only three leaflets in use, two from one hospital and one from an AIDS Charity. A content evaluation of the leaflets revealed varying readability, elements of bias and presentation factors which may all affect the usefulness of such leaflets. An in depth qualitative group on the leaflet with highest readability revealed particular concerns and highlighted the fact that the leaflets could be seen as additions and addendums to counselling but were not sufficient in themselves.

Counseling↗
PubMed2005

Assessment of construct validity of the endoscopic sinus surgery simulator.

OBJECTIVE: To study the relationship between performance on an endoscopic sinus surgery simulator (ES3) and fundamental perceptual, visuospatial, and psychomotor abilities. DESIGN: Validation study. SETTING: Tertiary care medical center. PARTICIPANTS: Thirty-four medical students and 4 otolaryngology residents voluntarily enrolled. INTERVENTIONS: Subjects performed tasks on the ES3, minimally invasive surgical trainer virtual reality (MIST-VR), pictorial surface orientation (PicSOr), and 3 visuospatial tests (cube comparison, card rotation, and map planning). MAIN OUTCOME MEASURES: The MIST-VR was scored for time, task error, economy of hand movement, economy of diathermy, and total score. Scores were generated for the PicSOr task and visuospatial tests. Scores were correlated with time, accuracy, and total subscore on navigation, injection, and dissection tasks, as well as hazard score and total trial score on the ES3. RESULTS: The PicSOr score was statistically significantly correlated with the hazard score on the ES3 (r = 0.50, P < .001). Cube comparison (r = 0.43, P < .01) and card rotation (r = 0.45, P < .01) scores correlated significantly with the ES3 trial score, as did the MIST-VR total score and the ES3 trial score (r = 0.57, P < .001). In a multiple regression model, the PicSOr, cube comparison, and MIST-VR total scores were statistically significant predictors of ES3 performance (r = 0.63, P < .01). CONCLUSIONS: Scores on the ES3 correlate strongly with scores on previously validated measures of perceptual, visuospatial, and psychomotor performance. The ES3 provides a reliable assessment of factors that are important to the acquisition of minimally invasive surgical skills, demonstrating construct validity.

Computer Simulation↗
PubMed2006

Self-organisation and communication in groups of simulated and physical robots.

In social insects, both self-organisation and communication play a crucial role for the accomplishment of many tasks at a collective level. Communication is performed with different modalities, which can be roughly classified into three classes: indirect (stigmergic) communication, direct interactions and direct communication. The use of stigmergic communication is predominant in social insects (e.g. the pheromone trails in ants), where, however, direct interactions (e.g. antennation in ants) and direct communication (e.g. the waggle dance in honey bees) can also be observed. Taking inspiration from insect societies, we present an experimental study of self-organising behaviours for a group of robots, which exploit communication to coordinate their activities. In particular, the robots are placed in an arena presenting holes and open borders, which they should avoid while moving coordinately. Artificial evolution is responsible for the synthesis in a simulated environment of the robot's neural controllers, which are subsequently tested on physical robots. We study different communication strategies among the robots: no direct communication, handcrafted signalling and a completely evolved approach. We show that the latter is the most efficient, suggesting that artificial evolution can produce behaviours that are more adaptive than those obtained with conventional design methodologies. Moreover, we show that the evolved controllers produce a self-organising system that is robust enough to be tested on physical robots, notwithstanding the huge gap between simulation and reality.

Algorithms↗
PubMed2002

Training the novice in laparoscopy. More challenge is better.

BACKGROUND: Virtual reality simulation is effective in training the novice to perform basic laparoscopic skills. METHODS: Using the Minimally Invasive Surgery Training--Virtual Reality (MIST-VR) trainer, 27 honors high school students were tested at the easy level, prospectively randomized to eight training sessions at the easy (group A, n = 14) or medium (group B, n = 13) level, then retested at the easy level. RESULTS: Both groups were statistically similar at baseline. All scores improved significantly (50.1% to 81.3%) over the period of training (p < 0.05). Although the group A scores were significantly better than the group B scores throughout training (p < 0.05), on final testing at the easy level, group B surpassed group A for all the tasks except TransferPlace (p = 0.054). CONCLUSIONS: Virtual simulation is an effective laparoscopic training method for the novice, providing significant improvement in skill levels over a relatively short period. More challenging training seems to predict greater improvement over time and better final skill levels.

Adolescent↗
PubMedDate not supplied

A comparison of self-selectivity corrections in economic evaluations and outcomes research.

OBJECTIVE: Two alternative selectivity correction methods have been widely applied in the health economics literature: the sample selection model (SSM) and the multipart model (MPM). The difference between these two approaches results from their initial assumptions about the distribution of error terms. Because the distributional assumptions cannot be theoretically verified, the usefulness of the methods can only be evaluated by real world comparison. This article reviews and empirically tests the two alternative selectivity correction methods to give a reality-based evaluation. METHODS: Using a randomized sample of patients as the "gold standard," the SSM and MPM are applied to a nonrandomized sample of patients with an identical set of dependent and independent variables. By comparing the actual estimates of the two methods, we evaluate the robustness of the two approaches. RESULTS: The results show that neither method is empirically robust in replicating the results of the randomized trial. There is no consistent pattern in the coefficients from either selectivity-correction method for replicating the coefficients in the randomized sample. CONCLUSIONS: Researchers should be cautious in applying these correction methods, and any conclusions based on these approaches may need to be qualified.

Angioplasty, Balloon, Coronary↗
PubMed2006

Abnormal categorization and perceptual learning in patients with hippocampal damage.

Prevailing theory holds that the medial temporal lobe (MTL) subserves declarative memory exclusively, whereas nondeclarative memory is independent of this brain region. Recent studies in patients with amnesia, however, have shown that performance on declarative memory tasks may not always be dependent on a single MTL memory system, instead highlighting the critical role of anatomically distinct structures in processing different stimulus types. In particular, the hippocampus has been implicated in spatial memory, whereas perirhinal cortex seems critical for object memory. To assess whether stimulus type would also be a key dimension in nondeclarative memory, patients with selective hippocampal lesions were tested on simple categorization and perceptual learning of faces and virtual reality scenes. The patients demonstrated preserved categorization and perceptual learning of faces but abnormal performance when the stimuli to be discriminated were virtual reality scenes. These findings imply that stimulus type may be a more critical predictor of performance on memory tasks (declarative and nondeclarative) than previously thought. They also suggest that reports of good nondeclarative memory after MTL damage may, in some cases, simply reflect the use of stimuli that fail to tap the processes dependent on structures in this region, such as spatial processing in the case of the hippocampus.

Adult↗
PubMedDate not supplied

[Benzodiazepines and forensic aspects].

Adverse effects of benzodiazepines are well known since the first one was used in 1958 (chlordiazepoxide). The literature collects study-cases or rarely controlled studies concerning side effects or paradoxical reactions to benzodiazepines. They mostly described drowsiness and behavioral disinhibition, including increased well-being feeling but also hostility, rage access with feeling of invulnerability, serious crimes and sometimes homicides. Delusional, manic, confusional or depressive states are also pointed out. Rate for aggressive behaviour is 0.3 to 0.7% but distinction should be done between accidental or "idiosyncratic" reaction and voluntary sought disinhibition, clearly more frequent. No benzodiazepine has any specificity for these adverse effects but pharmacology, doses, associated drugs (or alcohol) and psychopathology interact to produce hazardous psychic states. Pharmacology: GABA induces a decrease in serotonin compound and vigilance. Pharmacokinetic: first dose effect or over-dose effect, short half-life, lipophily, affinity, digestive absorption, active metabolites interact. Psychopathology: age, alcohol association, psychological status (high initial level of hostility, impulsivity, frustration, personality disorder and depressive status). External conditions: chronic illness, affective and professional frustrations, physical or psychic exhaustion contribute also. Some benzodiazepines (flunitrazepam, diazepam, clorazepate, triazolam, alprazolam, lorazepam, for example) are more often concerned for pharmacokinetics characteristics but also prescription habits. Forensic aspects should be considered in case of homicide. Especially, reality of benzodiazepines consumption and awareness of the potential paradoxical reaction should be precisely evaluated. Special focus on voluntary induced disinhibition has to be done for forensic considerations. Relationship but also crime facilitations are sometimes consciously sought. Some benzodiazepines have already been identified for this use: flunitrazepam, clorazepate but also triazolam and temazepam in UK, alprazolam in USA. Flunitrazepam is prohibited in USA and considered as narcotics in France. A Swedish study showed that violent acts were more frequent and serious in juvenile offenders taking flunitrazepam/alcohol than other young offenders staying in the same correctional institution. They recommended classification of flunitrazepam as narcotic. A study from Belgium with drug addicts concluded in the same way and asked for an increased information of professionals and a more efficient control of the delivery. Before concluding to idiosyncratic effect, and then possibly to penal irresponsibility, the forensic approach should consider: firstly the reality of the benzodiazepines absorption and implication in committing violence (urine test, chronology, amnesia); secondly, the association of unusual behaviour and converging circumstances (pharmacological, pharmacokinetic, psychopathology, external conditions); thirdly the consumer's knowledge of the disinhibition effect. In our prison practice, we have to be particularly cautious as population frequently associates personality disorder, drug addiction and high level of frustration related to penitential context. Special information should be given to inmates when benzodiazepines are prescribed, but more extensively, a preventive strategy should be adopted in general population.

Aggression↗
PubMed1983

Card pull in projective testing.

Card pull, the tendency of the test stimuli to evoke or predispose certain cognitive and affective responses in the subject, is essential to the understanding and practice of projective testing. The basic instruction in projective testing employs the subjunctive mood to catalyze the dialectic between actuality and potentiality inherent in the projective stimulus. The subject is encouraged to play with the stimulus, to modify fact, to forsake the literal and the concrete, and to toy with the reality-stuff of the stimulus. Various conceptions of projective stimuli are reviewed and considered nondefinitive of projective testing. Projective testing is tentatively defined as a state of mind, a temporary but adaptive collusion shared between tester and subject which involves the former inviting the latter to modify a sample of reality.

Journal Article↗
PubMed2006

Navigation around London by a taxi driver with bilateral hippocampal lesions.

The time-scale of hippocampal involvement in supporting episodic memory remains a keenly debated topic, with disagreement over whether its role is temporary or permanent. Recently, there has been interest in how navigation by hippocampally-compromised patients in environments learned long ago speaks to this issue. However, identifying patients with damage that is primarily hippocampal, control subjects matched for navigation experience, and testing their in situ navigation, present substantial problems. We met these challenges by using a highly accurate and interactive virtual reality simulation of central London (UK) to assess the navigation ability of a licensed London taxi driver who had sustained bilateral hippocampal damage. In this test, patient TT and matched control taxi drivers drove a virtual London taxi along the streets they had first learned 40 years before. We found that the hippocampus is not required for general orientation in the city either in first person or survey perspectives, detailed topographical knowledge of landmarks and their spatial relationships, or even for active navigation along some routes. However, in his navigation TT was very reliant on main artery or 'A' roads, and became lost when navigation depended instead on non-A roads. We conclude that the hippocampus in humans is necessary for facilitating navigation in places learned long ago, particularly where complex large-scale spaces are concerned, and successful navigation requires access to detailed spatial representations.

Aged↗
PubMed1977

[Functional sequelae of Mendelson's syndrome. Myth or reality?].

Twenty patients having previously had a Mendelson's syndrome were subjected to a respiratory functional test. A syndrome of diffuse interstitial pulmonary fibrosis (DIPF) was found only in 3 cases examined shortly after the pneumopathy. In one of these cases, another examination done later showed signs of regressing fibrosis. The authors concluded that if a functional syndrome of DIPF occurred immediately after a Mendelson's pneumopathy, it eventually disappeared in the long term in most cases.

Adolescent↗