UNASSIGNED: The term Behavioral and Psychological Symptoms of Dementia (BPSD) covers a group of phenomenologically and medically distinct symptoms that rarely occur in isolation. Their therapy represents a major unmet medical need across dementias of different types, including Alzheimer\'s disease. Understanding of the symptom occurrence and their clusterization can inform clinical drug development and use of existing and future BPSD treatments.
UNASSIGNED: The primary aim of the present study was to investigate the ability of a commonly used principal component analysis to identify BPSD patterns as assessed by Neuropsychiatric Inventory (NPI).
UNASSIGNED: NPI scores from the Aging, Demographics, and Memory Study (ADAMS) were used to characterize reported occurrence of individual symptoms and their combinations. Based on this information, we have designed and conducted a simulation experiment to compare Principal Component analysis (PCA) and zero-inflated PCA (ZI PCA) by their ability to reveal true symptom associations.
UNASSIGNED: Exploratory analysis of the ADAMS database revealed overlapping multivariate distributions of NPI symptom scores. Simulation experiments have indicated that PCA and ZI PCA cannot handle data with multiple overlapping patterns. Although the principal component analysis approach is commonly applied to NPI scores, it is at risk to reveal BPSD clusters that are a statistical phenomenon rather than symptom associations occurring in clinical practice.
UNASSIGNED: We recommend the thorough characterization of multivariate distributions before subjecting any dataset to Principal Component Analysis.

UNASSIGNED: The purpose of this study was to investigate the relationship between race/ethnicity and post-concussive mental health (i.e., depressive, post-traumatic stress disorder [PTSD]) and neurobehavioral symptoms among service members, and whether this association differed by education level.
UNASSIGNED: The study sample consisted of 524 patients from a multidisciplinary US military outpatient treatment facility for post-concussive symptoms. Poisson regression with robust error variance was utilized to investigate outcome (i.e., clinically-elevated depressive [Patient Health Questionnaire-8 ≥15], PTSD [PTSD Checklist, DSM 5 ≥38] and neurobehavioral [Neurobehavioral Symptom Inventory >75th percentile] symptoms at admission and last follow-up in this cohort study. Modification by education level (low [no college degree] vs. high [associate\'s degree or higher]) was additionally evaluated.
UNASSIGNED: The relationship between race/ethnicity and mental health/neurobehavioral symptoms varied by education level (p-interaction: depressive symptoms = 0.002, PTSD symptoms = 0.035, neurobehavioral symptoms = 0.040). Specifically, non-Whites were at a significantly higher prevalence for clinically-elevated depressive symptoms post-treatment than Whites, but only among those with higher education level (PR = 2.22, CI = 1.37-3.59). A similar trend was demonstrated for PTSD and neurobehavioral symptoms.
UNASSIGNED: Military healthcare may need to increase depression-focused treatment options that are acceptable for racial/ethnic minority patients, particularly those with higher education, while they are recovering from comorbid traumatic brain injury.

Metabolic syndrome (MetS), a constellation of related metabolic risk factors, is a common comorbidity associated with cognitive difficulty in people living with HIV (PLWH). Neurobehavioral disturbances (e.g., behavioral manifestations of frontal-subcortical dysfunction) are also prevalent in HIV, yet the role MetS might play in HIV-associated neurobehavioral disturbances is unknown. Thus, we examined the link between MetS and neurobehavioral disturbances in PLWH. Participants included 215 adults (117 PLWH, 98 HIV-uninfected), aged 36 to 65 years, from a cohort study at the University of California San Diego. Using the Frontal Systems Behavior Scale, we captured neurobehavioral disturbances (apathy, disinhibition, and executive dysfunction). MetS was defined by the National Cholesterol Education Program\'s Adult Treatment Panel-III criteria. Covariates examined included demographic, neurocognitive impairment, and psychiatric characteristics. When controlling for relevant covariates, both HIV serostatus and MetS were independently associated with greater apathy and executive dysfunction. HIV, but not MetS, was associated with greater disinhibition. The present findings suggest an additive effect of HIV and MetS on specific neurobehavioral disturbances (apathy and executive dysfunction), underscoring the importance of identifying and treating both HIV and MetS to lessen central nervous system burden among PLWH.

The surgical brain injury model replicates neurosurgical brain parenchymal damage. Postsurgical brain edema correlates with postoperative neurological dysfunction. Intranasal administration is a proven method of delivering therapies to brain tissue. Thrombin preconditioning decreased brain edema and improved neurological outcomes in models of ischemic brain injury. We hypothesized thrombin preconditioning in surgical brain injury may improve postoperative brain edema and neurological outcomes. Adult male Sprague-Dawley rats (n = 78) weighing 285-355 g were randomly assigned to sham or pre-injury treatment: one-time pretreatment 1 day prior, one-time pretreatment 5 days prior, and daily preconditioning for 5 days prior. Treatment arms were divided into vehicle or thrombin therapies, and subdivided into intranasal (thrombin 5 units/50 μL 0.9 % saline) or intracerebral ventricular (thrombin 0.1 unit/10 μL 0.9 % saline) administration. Blinded observers performed neurological testing 24 h after brain injury followed immediately by measurement of brain water content. There was a significant difference in ipsilateral brain water content and neurological outcomes between all treatment groups and the sham group. However, there was no change in brain water content or neurological outcomes between thrombin- and vehicle-treated animals. Thrombin preconditioning did not significantly improve brain edema or neurological function in surgical brain injury in rats.

BACKGROUND: Persistent negative symptoms are an important area of clinical research. However, there is limited consensus on how to define positive and negative symptom severity thresholds for inclusion in clinical trials. From the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) dataset we evaluated the performance of varying baseline negative and positive symptom thresholds on baseline symptom severity, change from baseline, and negative symptom variance attributable to positive symptom change.
METHODS: In CATIE, we first identified the group of subjects lacking an exacerbation prior to study enrollment. Six subsets with varying baseline positive and negative symptom thresholds were then identified. Baseline characteristics were summarized; negative and positive symptom change from baseline through month 3 was calculated both as crude change and change adjusted for corresponding baseline scores. Sensitivity analyses and correlations were calculated to assess the extent to which negative symptom variance was attributable to positive symptom change.
RESULTS: More restrictive baseline symptom severity thresholds yielded a considerably smaller sample size and higher negative and lower positive symptoms at baseline. Unadjusted negative symptom change was greater with more restrictive criteria; when adjusted for baseline severity the magnitude of change was comparable across subsets. The amount of variance in negative symptom change attributed to positive symptom change was also comparable across subsets.
CONCLUSIONS: The use of restrictive positive and negative symptom thresholds yields a marked decrease in eligible sample size with no clear improvement in adjusted negative symptom change or amount of variance associated with positive symptom change.

Exposure to manganese (Mn) is associated with neurobehavioral effects. There is disagreement on whether commonly occurring exposures in welding, ferroalloy, and other industrial processes produce neurologically significant neurobehavioral changes representing parkinsonism. A review of methodological issues in the human epidemiological literature on Mn identified: (1) studies focused on idiopathic Parkinson disease without considering manganism, a parkinsonian syndrome; (2) studies with healthy worker effect bias; (3) studies with problematic statistical modeling; and (4) studies arising from case series derived from litigation. Investigations with adequate study design and exposure assessment revealed consistent neurobehavioral effects and attributable subclinical and clinical signs and symptoms of impairment. Twenty-eight studies show an exposure-response relationship between Mn and neurobehavioral effects, including 11 with continuous exposure metrics and six with three or four levels of contrasted exposure. The effects of sustained low-concentration exposures to Mn are consistent with the manifestations of early manganism, i.e., consistent with parkinsonism. This is compelling evidence that Mn is a neurotoxic chemical and there is good evidence that Mn exposures far below the current US standard of 5.0 mg/m(3) are causing impairment.