2,765 research outputs found

    Playing the Wrong Game: An Experimental Analysis of Relational Complexity and Strategic Misrepresentation.

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    It has been suggested that players often produce simplified and/or misspecified mental models of strategic decisions [Kreps, D., 1990. Game Theory and Economic Modeling. Oxford Univ. Press, Oxford]. We submit that the relational structure of players’ preferences in a game is a source of cognitive complexity, and may be an important driver of such simplifications. We provide a classification of order structures in two- person games based on the properties of monotonicity and projectivity, and present experiments in which subjects construct representations of games of different relational complexity and subsequently play the games according to these representations. Experimental results suggest that relational complexity matters. More complex games are harder to represent, and this difficulty seems correlated with short term memory capacity. In addition, most erroneous representations are simpler than the correct ones. Finally, subjects who misrepresent the games behave consistently with such representations, suggesting that in many strategic settings individuals may act optimally on the ground of simplified and mistaken premises

    Content Analysis of Four Fear of Falling Rating Scales by Linking to the International Classification of Functioning, Disability and Health.

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    OBJECTIVE: To gain a deeper understanding of the content of 4 fear of falling (FOF) rating scales by linking them to the International Classification of Functioning, Disability and Health (ICF). DESIGN: Linking study according to the ICF linking rules. SETTING: Not applicable. PATIENTS: Not applicable. METHODS: The rating scales were the Falls Efficacy Scale-International (FES-I), the Swedish version of the Falls Efficacy Scale (FES[S]), the Activities-specific Balance Confidence Scale (ABC), and the modified Survey of Activities and Fear of Falling in the Elderly (SAFFE). The process followed the established and updated linking rules. Three linkers independently identified all meaningful concepts in the rating scales and linked them to the most precise ICF categories. The linkers then discussed their results to reach consensus. If consensus was not attained, the linkers pursued the discussions with a fourth person to reach consensus. MAIN OUTCOME MEASUREMENTS: Not applicable. RESULTS: Most meaningful concepts from the overall questions were linked to the ICF component of body functions. Of the 62 items, all but one meaningful concept were linked to the component of activities and participation. All 4 rating scales covered the chapters of mobility and domestic life and had most linkages to the mobility chapter. CONCLUSIONS: The linking process revealed similarities and differences between the 4 FOF rating scales, as well as methodologic challenges in linking instruments to the ICF. By providing a content description that allows for a direct comparison of the rating scales, the results may be helpful when choosing an appropriate rating scale assessing FOF in clinical practice and research. A further head-to-head comparison through psychometric analyses is required to recommend appropriate FOF rating scales. Studies are also needed to investigate how the overall question and response categories of a rating scale affect respondents' answers

    Uncovering Indicators of the International Classification of Functioning, Disability, and Health from the 39-Item Parkinson's Disease Questionnaire

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    The 39-item Parkinson's disease questionnaire (PDQ-39) is the most widely used patient-reported rating scale in Parkinson's disease (PD). However, recent studies have questioned its validity and it is unclear what scores represent. This study explored the possibility of regrouping PDQ-39 items into scales representing the International Classification of Functioning, Disability, and Health (ICF) components of Body Functions and Structures (BF), Activities and Participation (AP), and Environmental (E) factors. An iterative process using Rasch analysis produced five new items sets, two each for the BF and AP components and one representing E. Four of these were found to represent clinically meaningful variables: Emotional Impairment (BF), Gross Motor Disability (AP), Fine Motor Disability (AP), and Socioattitudinal Environment (E) with acceptable reliability (0.73–0.96) and fit to the Rasch model (total item-trait chi-square, 8.28–33.2; P > .05). These new ICF-based scales offer a means to reanalyze PDQ-39 data from an ICF perspective and to study its health components using a widely available health status questionnaire for people with PD

    Walking Ability Is a Major Contributor to Fear of Falling in People with Parkinson's Disease: Implications for Rehabilitation

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    Although fear of falling (FOF) is common in people with Parkinson's disease (PD), there is a lack of research investigating potential predictors of FOF. This study explored the impact of motor, nonmotor, and demographic factors as well as complications of drug therapy on FOF among people with PD. Postal survey data (including the Falls Efficacy Scale, FES) from 154 nondemented people with PD were analyzed using multiple regression analyses. Five significant independent variables were identified explaining 74% of the variance in FES scores. The strongest contributing factor to FOF was walking difficulties (explaining 68%), followed by fatigue, turning hesitations, need for help in daily activities, and motor fluctuations. Exploring specific aspects of walking identified three significant variables explaining 59% of FOF: balance problems, limited ability to climb stairs, and turning hesitations. These results have implications for rehabilitation clinicians and suggest that walking ability is the primary target in order to reduce FOF. Specifically, balance, climbing stairs, and turning seem to be of particular importance

    Development and testing of a self administered version of the Freezing of Gait Questionnaire

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    Background: The Freezing of Gait Questionnaire (FOGQ) was developed in response to the difficulties of observing and quantifying freezing of gait (FOG) clinically as well as in laboratory settings. However, as the FOGQ is a clinician-administered patient-reported rating scale it cannot be used in postal surveys. Here we report the development and measurement properties of a self-administered version of the FOGQ (FOGQsa). Methods: A clinical sample and a postal survey sample of non-demented people with Parkinson's disease (PD; total n = 225) completed the FOGQsa and questionnaires concerning physical functioning (PF) and fall-related self efficacy (FES). Additional questions (No/Yes) regarded previous falls and whether they were afraid of falling. The clinical sample was also assessed with the Unified PD Rating Scale (UPDRS). Thirty-five participants completed FOGQsa and were also assessed with the original version (FOGQ) in a clinical interview. Results: There were no differences (P = 0.12) between FOGQ (median, 10; q1-q3, 2-14) and FOGQsa (median, 8; 214) scores. The Spearman (r(s)) and intra-class correlations between the two were 0.92 and 0.91 (95% CI, 0.82-0.95), respectively. For FOGQsa, corrected item-total correlations ranged between 0.68-0.89. Reliability was 0.93 (95% CI, 0.91-0.94). FOGQsa scores correlated strongest with UPDRS Item 14 (Freezing; r(s), 0.76) and with FES (r(s), -0.74). The weakest correlation was found with age (r(s), 0.14). Fallers scored significantly (p < 0.001) higher on FOGQsa compared to non-fallers, median scores 8 (q1-q3, 4-14) versus 2 (0-7). Those expressing a fear of falling scored higher (p < 0.001) than those who did not, median scores 2 (0-7) versus 6 (2-14). Conclusions: The present findings indicate that the FOGQsa is as reliable and valid as the original interview administered FOGQ version. This has important clinical implications when investigating FOG in large scale studies

    A New Tool for Assessing Environmental Impacts of Altering Short-Term Flow and Water Level Regimes

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    The computational tool InSTHAn (indicators of short-term hydrological alteration) was developed to summarize data on subdaily stream flows or water levels into manageable, comprehensive and ecologically meaningful metrics, and to qualify and quantify their deviation from unaltered states. The pronunciation of the acronym refers to the recording interval of input data (i.e., instant). We compared InSTHAn with the tool COSH-Tool in a characterization of the subdaily flow variability of the Colorado River downstream from the Glen Canyon dam, and in an evaluation of the effects of the dam on this variability. Both tools captured the hydropeaking caused by a dam operation, but only InSTHAn quantified the alteration of key flow attributes, highlighting significant increases in the range of within-day flow variations and in their rates of change. This information is vital to evaluate the potential ecological consequences of the hydrological alteration, and whether they may be irreversible, making InSTHAn a key tool for river flow management

    CD8+ T cell activation predominate early immune responses to hypercholesterolemia in Apoe-/- mice

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    <p>Abstract</p> <p>Background</p> <p>It is well established that adaptive immune responses induced by hypercholesterolemia play an important role in the development of atherosclerosis, but the pathways involved remain to be fully characterized. In the present study we assessed immune responses to hypercholesterolemia induced by feeding <it>Apoe<sup>-/- </sup></it>mice a high-fat diet for 4 or 8 weeks.</p> <p>Results</p> <p>The primary immune response in lymph nodes draining the aortic root was an increased expression of interferon (IFN)-γ in CD8<sup>+</sup>CD28<sup>+ </sup>T cells, while an activation of IFN-γ expression in CD4<sup>+ </sup>T cells was observed only after 8 weeks of high-fat diet. Contrarily, spleen CD4<sup>+ </sup>T cells responded with a higher expression of IL-10. Spleen CD8<sup>+ </sup>T cells expressed both IFN-γ and IL-10 and showed enhanced proliferation when exposed to Concanavalin A. Plasma levels of IgG and IgM against oxidized LDL did not change, but the level of apolipoprotein B/IgM immune complexes was increased.</p> <p>Conclusion</p> <p>Hypercholesterolemia leads to unopposed activation of Th1 immune responses in lymph nodes draining atherosclerotic lesions, whereas Th1 activation in the spleen is balanced by a concomitant activation of Th2 cells. The activation of CD8<sup>+ </sup>T cells implies that hypercholesterolemia is associated with formation of cell autoantigens.</p

    Subthalamic deep brain stimulation improves smooth pursuit and saccade performance in patients with Parkinson’s disease

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    © 2013 The Authors. Published by BMC. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1186/1743-0003-10-33Deep brain stimulation (DBS) in the subthalamic nucleus (STN) significantly reduces symptoms of Parkinson’s disease (PD) such as bradykinesia, tremor and rigidity. It also reduces the need for anti-PD medication, and thereby potential side-effects of L-Dopa. Although DBS in the STN is a highly effective therapeutic intervention in PD, its mechanism and effects on oculomotor eye movement control and particularly smooth pursuit eye movements have to date rarely been investigated. Furthermore, previous reports provide conflicting information. The aim was to investigate how DBS in STN affected oculomotor performance in persons with PD using novel analysis techniques. Methods Twenty-five patients were eligible (22 males, 3 females) according to the clinical inclusion criteria: idiopathic PD responsive to L-Dopa and having had bilateral STN stimulation for at least one year to ensure stable DBS treatment. Fifteen patients were excluded due to the strict inclusion criteria applied to avoid interacting and confounding factors when determining the effects of DBS applied alone without PD medication. One patient declined participation. Nine PD patients (median age 63, range 59–69 years) were assessed after having their PD medications withdrawn overnight. They were examined with DBS ON and OFF, with the ON/OFF order individually randomized. Results DBS ON increased smooth pursuit velocity accuracy (p < 0.001) and smooth pursuit gain (p = 0.005), especially for faster smooth pursuits (p = 0.034). DBS ON generally increased saccade amplitude accuracy (p = 0.007) and tended to increase peak saccade velocity also (p = 0.087), specifically both saccade velocity and amplitude accuracy for the 20 and 40 degree saccades (p < 0.05). Smooth pursuit latency tended to be longer (p = 0.090) approaching normal with DBS ON. Saccade latency was unaffected. Conclusions STN stimulation from DBS alone significantly improved both smooth pursuit and saccade performance in patients with PD. The STN stimulation enhancement found for oculomotor performance suggests clear positive implications for patients’ ability to perform tasks that rely on visual motor control and visual feedback. The new oculomotor analysis methods provide a sensitive vehicle to detect subtle pathological modifications from PD and the functional enhancements produced by STN stimulation from DBS alone.The authors’ wish to acknowledge the financial supported from the Swedish Medical Research Council (grant nr. 17x-05693), the Medical Faculty, Lund University, Sweden, and the Swedish Parkinson Academy. This study was performed within the Strategic Research Area Multipark at Lund University and within the context of the Centre for Ageing and Supportive environments (CASE), Lund University, Sweden, funded by the Swedish Council for Working Life and Social Research.Published versio

    Comprehensive sex steroid profiling in multiple tissues reveals novel insights in sex steroid distribution in male mice

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    A comprehensive atlas of sex steroid distribution in multiple tissues is currently lacking, and how circulating and tissue sex steroid levels correlate remains unknown. Here, we adapted and validated a gas chromatography tandem mass spectrometry method for simultaneous measurement of testosterone (T), dihydrotestosterone (DHT), androstenedione, progesterone (Prog), estradiol, and estrone in mouse tissues. We then mapped the sex steroid pattern in 10 different endocrine, reproductive, and major body compartment tissues and serum of gonadal intact and orchiectomized (ORX) male mice. In gonadal intact males, high levels of DHT were observed in reproductive tissues, but also in white adipose tissue (WAT). A major part of the total body reservoir of androgens (T and DHT) and Prog was found in WAT. Serum levels of androgens and Prog were strongly correlated with corresponding levels in the brain while only modestly correlated with corresponding levels in WAT. After orchiectomy, the levels of the active androgens T and DHT decreased markedly while Prog levels in male reproductive tissues increased slightly. In ORX mice, Prog was by far the most abundant sex steroid, and, again, WAT constituted the major reservoir of Prog in the body. In conclusion, we present a comprehensive atlas of tissue and serum concentrations of sex hormones in male mice, revealing novel insights in sex steroid distribution. Brain sex steroid levels are well reflected by serum levels and WAT constitutes a large reservoir of sex steroids in male mice. In addition, Prog is the most abundant sex hormone in ORX mice
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