798 Diffusion tensor imaging as a potential biomarker of sleep dysfunction in warfighters with chronic, severe, traumatic brain injury

Introduction Traumatic brain injury (TBI) plagues service members in times of war and training. Diagnosis and management of TBI remain challenging, with many suffering from sleep disorders. We hypothesized that TBI-related damage to the hypothalamus, a master regulator of breathing and sleep, could be related to post-TBI obstructive sleep apnea (OSA) and serve as a pathophysiological biomarker for a subpopulation of OSA patients. Methods This was a retrospective study of warfighters with TBI from the National Intrepid Center of Excellence (NICoE). Subjects were identified by severe TBI on neuroimaging and compared against a control group without TBI. All subjects underwent screening polysomnography (PSG). MRI was acquired via 3T scanner. The hypothalamus was automatically segmented using a diffeomorphic algorithm. DTI scalar values were analyzed with scalar t-tests between subjects and controls. Generalized linear modeling with DTI scalar values was used to predict AHI in subjects. Results 6 subjects and 61 controls were identified. There was significant sleep dysfunction amongst TBI subjects (mean apnea-hypopnea index (AHI) 5.1+/-6.6 events/hour; mild OSA incidence 33.3%; Pittsburgh Sleep Quality Index (PSQI) mean 13.3+/-2.6). Radial diffusivity (RD), axial diffusivity (AD) and mean diffusivity (MD) were significantly higher among subjects (control RD 9.64x10^-10+/-7.54x10^-11 m^2/s, subject RD 1.13x10^-9+/-1.20x10^-10m^2/s, p = 0.023; control AD 1.32x10^-9+/-7.64x10^-11m^2/s, subject AD 1.50x10^-9+/-1.43x10^-10m^2/s, p = 0.029; control MD 1.08x10^-9+/-7.43x10^-11m^2/s, subject MD 1.25x10^-9+/-1.34x10^-10m^2/s, p = 0.025). There were no differences in age or body-mass index. Generalized linear modeling with diffusivity measures as predictors of AHI in subjects was not significant. Conclusion Using a diffeomorphic algorithm to define the hypothalamus reveals significantly elevated scalar DTI measures in chronic, severe TBI compared to controls. DTI differences in the hypothalamus are a novel finding and possibly underlie part of the pathophysiology of TBI. Although this may have potential to serve as a biomarker in severe TBI patients with sleep disorders, these initial data do not support a relationship between DTI and AHI, despite high incidence of OSA and subjective sleep dysfunction. Future studies with more subjects may better elucidate the changes in hypothalamic DTI after TBI for clinical outcomes analysis. Support (if any) This work was supported by grant 130132 from USAMRMC.

The Effects of Victimization Prior to Prison on Victimization, Misconduct, and Sanction Severity During Incarceration

Numerous studies have examined the correlation between physical and/or sexual victimization and offending and re-victimization later in life. However, fewer studies have explored how such victimization affects the adjustment of those incarcerated and the sanctioning decisions of correctional personnel. Using a nationally representative sample of inmates in state prisons, this study utilized hierarchical generalized linear modeling to examine whether victimization prior to incarceration was associated with the likelihood of victimization, misconduct, and sanctioning severity for misconduct during incarceration. Our results confirmed findings of previous research in regards to the victimization and offending/re-victimization relationship. In addition, we discovered that victimization prior to prison is associated with harsher disciplinary sanctioning in prison. Implications of our findings for research and policy are discussed.

Dystonia & tremor: A cross-sectional study of the dystonia coalition cohort

Objective:To assess the clinical manifestations and predictors of different types of tremors in a individuals with different types of isolated dystonia.Methods:Clinical manifestations of tremor were assessed in a multicenter, international cross-sectional, cohort study of 2362 individuals with all types of isolated dystonia (focal, segmental, multifocal and generalized) recruited through the Dystonia Coalition.Results:Methodical and standardized assessments of all subjects in this cohort revealed the overall prevalence of any type of tremor was 53.3%. The prevalence of dystonic tremor varied from 36.9-48.4%, depending on criteria used to define it. To identify the factors associated with tremors in dystonia, the data were analyzed by generalized linear modeling and cluster analyses. Generalized linear modeling indicated two of the strongest factors associated with tremor included body region affected by dystonia and recruitment center. Tremor was also associated with severity of dystonia and duration of dystonia, but not with sex or race. The cluster analysis distinguished eight subgroups within the whole cohort; defined largely by body region affected with dystonia, and secondarily by other clinical characteristics.Conclusion:The large number of cases evaluated by an international team of movement disorder experts facilitated the dissection of several important factors that influence the apparent prevalence and phenomenology of tremor in dystonia. These results are valuable for understanding the many differences reported in prior studies, and for guiding future studies of the nosology of tremor and dystonia.

Quality of Information Regarding Repair Restorations on Dentist Websites: Systematic Search and Analysis

Background Repairing instead of replacing partially defective dental restorations represents a minimally invasive treatment concept, and repairs are associated with advantages over complete restoration replacement. To participate in the shared decision-making process when facing partially defective restorations, patients need to be aware of the indications, limitations, and advantages or disadvantages of repairs. Patients are increasingly using the internet to gain health information like this online. Objective We aimed to assess the quality of German-speaking dentist websites on repairs of partially defective restorations. Methods Three electronic search engines were used to identify German-speaking websites of dental practices mentioning repairs. Regarding information on repairs, websites were assessed for (1) technical and functional aspects, (2) comprehensiveness of information, and (3) generic quality and risk of bias. Domains 1 and 3 were scored using validated tools (LIDA and DISCERN). Comprehensiveness was assessed using a criterion checklist related to evidence, advantages and disadvantages, restorations and defects suitable for repairs, and information regarding technical implementation. Generalized linear modeling was used to assess the impact of practice-specific parameters (practice location, practice setting, dental society membership, and year of examination or license to practice dentistry) on the quality of information. An overall quality score was calculated by averaging the quality scores of all three domains and used as primary outcome parameter. Quality scores of all three domains were also assessed individually and used as secondary outcomes. Results Fifty websites were included. The median score of quality of information was 23.2% (interquartile range [IQR] 21.7%-26.2%). Technical and functional aspects (55.2% [IQR 51.7%-58.6%]) showed significantly higher quality than comprehensiveness of information (8.3% [IQR 8.3%-16.7%]) and generic quality and risk of bias (3.6% [IQR 0.0%-7.1%]; P<.001/Wilcoxon). Quality scores were not related to practice-specific parameters (P>.05/generalized linear modeling). Conclusions The quality of German-speaking dentist websites on repairs was limited. Despite sufficient technical and functional quality, the provided information was neither comprehensive nor trustworthy. There is great need to improve the quality of information to fully and reliably inform patients, thereby allowing shared decision making.

Stock Movement Modeling Based on the Analysis of Negative Correlation

This research presents the data-driven modeling method to derive a combined trading model from the analysis of negative correlations among the top-five active stocks from each sector of the Thailand stock market. The negative movements are computed from the closing price direction of major stocks in the eight biggest sectors. The highly negative correlated stocks among market groups are then used to build predictive trading models with three algorithms: regression analysis, generalized linear modeling, and chi-square automatic interaction detection. An ensemble from the combination of the best two models is then created. The experimental results reveal that the proposed method of trading based on negative movement analysis can accurately predict closing price of the active stock with low error rate around 1.86%.

Quality of Information Regarding Repair Restorations on Dentist Websites: Systematic Search and Analysis (Preprint)

BACKGROUND Repairing instead of replacing partially defective dental restorations represents a minimally invasive treatment concept, and repairs are associated with advantages over complete restoration replacement. To participate in the shared decision-making process when facing partially defective restorations, patients need to be aware of the indications, limitations, and advantages or disadvantages of repairs. Patients are increasingly using the internet to gain health information like this online. OBJECTIVE We aimed to assess the quality of German-speaking dentist websites on repairs of partially defective restorations. METHODS Three electronic search engines were used to identify German-speaking websites of dental practices mentioning repairs. Regarding information on repairs, websites were assessed for (1) technical and functional aspects, (2) comprehensiveness of information, and (3) generic quality and risk of bias. Domains 1 and 3 were scored using validated tools (LIDA and DISCERN). Comprehensiveness was assessed using a criterion checklist related to evidence, advantages and disadvantages, restorations and defects suitable for repairs, and information regarding technical implementation. Generalized linear modeling was used to assess the impact of practice-specific parameters (practice location, practice setting, dental society membership, and year of examination or license to practice dentistry) on the quality of information. An overall quality score was calculated by averaging the quality scores of all three domains and used as primary outcome parameter. Quality scores of all three domains were also assessed individually and used as secondary outcomes. RESULTS Fifty websites were included. The median score of quality of information was 23.2% (interquartile range [IQR] 21.7%-26.2%). Technical and functional aspects (55.2% [IQR 51.7%-58.6%]) showed significantly higher quality than comprehensiveness of information (8.3% [IQR 8.3%-16.7%]) and generic quality and risk of bias (3.6% [IQR 0.0%-7.1%]; <i>P</i>&lt;.001/Wilcoxon). Quality scores were not related to practice-specific parameters (<i>P</i>&gt;.05/generalized linear modeling). CONCLUSIONS The quality of German-speaking dentist websites on repairs was limited. Despite sufficient technical and functional quality, the provided information was neither comprehensive nor trustworthy. There is great need to improve the quality of information to fully and reliably inform patients, thereby allowing shared decision making.

Understanding School Principal Attrition and Mobility Through Hierarchical Generalized Linear Modeling

Despite a growing body of turnover literature, much remains unknown about the factors predicting career transitional behaviors of school principals. To bridge this gap, we examined variations in principal, school, and district characteristics influencing administrator leaver and mover behaviors, using Hierarchical Generalized Linear Modeling. Our findings revealed that class size, support staff, parental involvement, teacher incentives, unionization, and many other district-level policies offset turnover, thereby contributing to retention. Furthermore, predictors of principal mover behavior differed from those of principal leaver behavior, suggesting that different forms of exit paths may need different policy tools to improve retention.