1,068 research outputs found

    Psychiatric and medical admissions observed among elderly patients with new-onset epilepsy

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    <p>Abstract</p> <p>Background</p> <p>Inpatient utilization associated with incidence of geriatric new-onset epilepsy has not been characterized in any large study, despite recognized high levels of risk factors (comorbidity).</p> <p>Methods</p> <p>Retrospective study using administrative data (Oct '01-Sep '05) from the Veterans Health Administration from a nationwide sample of 824,483 patients over age 66 in the retrospective observational Treatment In Geriatric Epilepsy Research (TIGER) study. Psychiatric and medical hospital admissions were analyzed as a function of patient demographics, comorbid psychiatric, neurological, and other medical conditions, and new-onset epilepsy.</p> <p>Results</p> <p>Elderly patients experienced a 15% hospitalization rate in FY00 overall, but the subset of new-onset epilepsy patients (n = 1,610) had a 52% hospitalization rate. New-onset epilepsy was associated with three-fold increased relative odds of psychiatric admission and nearly five-fold increased relative odds of medical admission. Among new-onset epilepsy patients, alcohol dependence was most strongly associated with psychiatric admission during the first year after epilepsy onset (odds ratio = 5.2; 95% confidence interval 2.6-10.0), while for medical admissions the strongest factor was myocardial infarction (odds ratio = 4.7; 95% confidence interval 2.7-8.3).</p> <p>Conclusion</p> <p>From the patient point of view, new-onset epilepsy was associated with an increased risk of medical admission as well as of psychiatric admission. From an analytic perspective, omitting epilepsy and other neurological conditions may lead to overestimation of the risk of admission attributable solely to psychiatric conditions. Finally, from a health systems perspective, the emerging picture of the epilepsy patient with considerable comorbidity and demand for healthcare resources may merit development of practice guidelines to improve coordinated delivery of care.</p

    Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects

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    <p>Abstract</p> <p>Background</p> <p>Long-term potentiation (LTP) and long-term depression (LTD) play important roles in mediating activity-dependent changes in synaptic transmission and are believed to be crucial mechanisms underlying learning and cortical plasticity. In human subjects, however, the lack of adequate input stimuli for the induction of LTP and LTD makes it difficult to study directly the impact of such protocols on behavior.</p> <p>Results</p> <p>Using tactile high- and low-frequency stimulation protocols in humans, we explored the potential of such protocols for the induction of perceptual changes. We delivered tactile high-frequency and low-frequency stimuli (t-HFS, t-LFS) to skin sites of approximately 50 mm<sup>2 </sup>on the tip of the index finger. As assessed by 2-point discrimination, we demonstrate that 20 minutes of t-HFS improved tactile discrimination, while t-LFS impaired performance. T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster. While t-HFS changes were spatially very specific with no changes on the neighboring fingers, impaired tactile performance after t-LFS was also observed on the right middle-finger. A central finding was that for both t-LFS and t-HFS perceptual changes were dependent on the size of the stimulated skin area. No changes were observed when the stimulated area was very small (< 1 mm<sup>2</sup>) indicating special requirements for spatial summation.</p> <p>Conclusion</p> <p>Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.</p

    LD-Spline: Mapping SNPs on genotyping platforms to genomic regions using patterns of linkage disequilibrium

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    <p>Abstract</p> <p>Background</p> <p>Gene-centric analysis tools for genome-wide association study data are being developed both to annotate single locus statistics and to prioritize or group single nucleotide polymorphisms (SNPs) prior to analysis. These approaches require knowledge about the relationships between SNPs on a genotyping platform and genes in the human genome. SNPs in the genome can represent broader genomic regions via linkage disequilibrium (LD), and population-specific patterns of LD can be exploited to generate a data-driven map of SNPs to genes.</p> <p>Methods</p> <p>In this study, we implemented LD-Spline, a database routine that defines the genomic boundaries a particular SNP represents using linkage disequilibrium statistics from the International HapMap Project. We compared the LD-Spline haplotype block partitioning approach to that of the four gamete rule and the Gabriel et al. approach using simulated data; in addition, we processed two commonly used genome-wide association study platforms.</p> <p>Results</p> <p>We illustrate that LD-Spline performs comparably to the four-gamete rule and the Gabriel et al. approach; however as a SNP-centric approach LD-Spline has the added benefit of systematically identifying a genomic boundary for each SNP, where the global block partitioning approaches may falter due to sampling variation in LD statistics.</p> <p>Conclusion</p> <p>LD-Spline is an integrated database routine that quickly and effectively defines the genomic region marked by a SNP using linkage disequilibrium, with a SNP-centric block definition algorithm.</p

    EEG Correlates of Attentional Load during Multiple Object Tracking

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    While human subjects tracked a subset of ten identical, randomly-moving objects, event-related potentials (ERPs) were evoked at parieto-occipital sites by task-irrelevant flashes that were superimposed on either tracked (Target) or non-tracked (Distractor) objects. With ERPs as markers of attention, we investigated how allocation of attention varied with tracking load, that is, with the number of objects that were tracked. Flashes on Target discs elicited stronger ERPs than did flashes on Distractor discs; ERP amplitude (0–250 ms) decreased monotonically as load increased from two to three to four (of ten) discs. Amplitude decreased more rapidly for Target discs than Distractor discs. As a result, with increasing tracking loads, the difference between ERPs to Targets and Distractors diminished. This change in ERP amplitudes with load accords well with behavioral performance, suggesting that successful tracking depends upon the relationship between the neural signals associated with attended and non-attended objects

    Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Z Resonance

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    This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.Comment: 79 pages, 16 figures, Accepted by Eur. Phys. J.

    A Determination of the Centre-of-Mass Energy at LEP2 using Radiative 2-fermion Events

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    Using e+e- -> mu+mu-(gamma) and e+e- -> qqbar(gamma) events radiative to the Z pole, DELPHI has determined the centre-of-mass energy, sqrt{s}, using energy and momentum constraint methods. The results are expressed as deviations from the nominal LEP centre-of-mass energy, measured using other techniques. The results are found to be compatible with the LEP Energy Working Group estimates for a combination of the 1997 to 2000 data sets.Comment: 20 pages, 6 figures, Accepted by Eur. Phys. J.

    A Measurement of the Tau Hadronic Branching Ratios

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    The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h- v_t, h- pi0 v_t, h- pi0 pi0 v_t, h- \geq 2pi0 v_t, h- \geq 3pi0 v_t, 2h- h+ v_t, 2h- h+ pi0 v_t, 2h- h+ \geq 2pi0 v_t, 3h- 2h+ v_t and 3h- 2h+ \geq 1pi0 v_t) were measured with data from the DELPHI detector at LEP.Comment: 53 pages, 18 figures, Accepted by Eur. Phys. J.

    Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP

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    Sleptons, neutralinos and charginos were searched for in the context of scenarios where the lightest supersymmetric particle is the gravitino. It was assumed that the stau is the next-to-lightest supersymmetric particle. Data collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were analysed combining the methods developed in previous searches at lower energies. No evidence for the production of these supersymmetric particles was found. Hence, limits were derived at 95% confidence level.Comment: 31 pages, 14 figure
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