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To determine the association between blood markers of white matter injury (e.g., serum neurofilament light and phosphorylated neurofilament heavy) and a novel neuroimaging technique measuring microstructural white matter changes (e.g., diffusion kurtosis imaging) in regions (e.g., anterior thalamic radiation and uncinate fasciculus) known to be impacted in traumatic brain injury (TBI) and associated with symptoms common in those with chronic TBI (e.g., sleep disruption, cognitive and emotional disinhibition) in a heterogeneous sample of Veterans and non-Veterans with a history of remote TBI (i.e., >6 months).
Participants and Methods:
Participants with complete imaging and blood data (N=24) were sampled from a larger multisite study of chronic mild-moderate TBI. Participants ranged in age from young to middle-aged (mean age = 34.17, SD age = 10.96, range = 19-58) and primarily male (66.7%). The number of distinct TBIs ranged from 1-5 and the time since most recent TBI ranged from 0-30 years. Scores on a cognitive screener (MoCA) ranged from 22-30 (mean = 26.75). We performed bivariate correlations with mean kurtosis (MK) in the anterior thalamic radiation (ATR; left, right) uncinate fasciculus (UF; left, right), and serum neurofilament light (NFL), and phosphorylated neurofilament heavy (pNFH). Both were log transformed for non-normality. Significance threshold was set at p<0.05.
Results:
pNFH was significantly and negatively correlated to MK in the right (r=-0.446) and left (r=-0.599) UF and right (r=-0.531) and left (r=-0.469) ATR. NFL showed moderate associations with MK in the right (r=-0.345) and left (r=-0.361) UF and little to small association in the right (r=-0.063) and left (r=-0.215) ATR. In post-hoc analyses, MK in both the left (r=0.434) and right (r=0.514) UF was positively associated with performance on a frontally-mediated list-learning task (California Verbal Learning Test, 2nd Edition; Trials 1-5 total).
Conclusions:
Results suggest that serum pNFH may be a more sensitive blood marker of microstructural complexity in white matter regions frequently impacted by TBI in a chronic mild-moderate TBI sample. Further, it suggests that even years after a mild-moderate TBI, levels of pNFH may be informative regarding white matter integrity in regions related to executive functioning and emotional disinhibition, both of which are common presenting problems when these patients are seen in a clinical setting.
To determine the association between in-vivo spectroscopy metabolite data, the local connectome, and markers of initial injury severity (I.e., history of loss of consciousness; LoC) in traumatic brain injury (TBI), in a heterogenous sample of Veterans and non-Veterans with a history of remote mild-to-moderate TBI (I.e., >6 months).
Participants and Methods:
Participants with complete PRESS magnetic resonance spectroscopy (MRS) and diffusion weighted imaging (DWI) data (N = 41) were sampled from a larger multisite study of chronic mild-to-moderate TBI (Nmiid = 38; Nmoderate = 3; 54% with LoC; 46% with multiple TBI). The sample was predominantly male (76%) with ages ranging from 23-59 (M = 36.9, SD = 10.1), with 98% holding at least a high school degree (M = 14.5 years of education, SD = 2.4). Fully tissue-and-relaxation-corrected metabolite concentration estimates in the dorsal anterior cingulate (30x30x30mm voxel) were modeled using Osprey 2.4.0. Total creatine (tCr), total choline (tCho), total N-acetylaspartate (tNAA), glutamate/glutamine (Glx), and myo-inositol (mI) were analyzed. Logistic regression was used to measure the association between metabolites and history of TBI with LoC. Correlational connectometry using the normalized spin distribution function was performed for metabolites associated with LoC, to characterize the local connectome associated with metabolites of interest, controlling for age and sex, and correcting for multiple comparisons (FDR < .050 with 4000 permutations). A profile approach was used to interpret diffusion metrics, contrasting quantitative anisotropy (QA) with fractional anisotropy (FA). Local connectome tracks were then clustered to identify the larger white matter tract.
Results:
Glx (p = .008) and tCr (p = .032) were significantly associated with history of TBI with LoC. Increased Glx was associated with increased QA in 11,001 tracks, accounting for 1.4% of the total white matter tracks in the brain. 90% of tracks were identified in bilateral cingulum (33%), bilateral thalamic (13%), bilateral corticospinal (13%), corpus callosum (12%), left arcuate fasciculus (9%), left frontoparietal aslant tracts (6%), and bilateral inferior fronto-occipital fasciculus (4%) tracts. In contrast, FA was not associated with Glx. The same pattern emerged for tCr, with 10,542 tracks identified predominantly in bilateral cingulum (29%), corpus callosum (21%), bilateral corticospinal (15%), bilateral corticostriatal (7%), bilateral medial lemniscus (7%), left cortico-pontine (3%), left thalamic (2%), and bilateral superior longitudinal fasciculus (2%) tracts. Post-hoc exploratory analyses of mean QA across regions of cingulum found that increased QA was associated with self-report measures of headache intensity, fatigue, and perceived change in executive functioning.
Conclusions:
Results provided evidence that multimodal imaging can identify subtle markers of initial TBI severity years after injury. Neurometabolite concentrations were associated with diffuse changes in the local connectome; the pattern of discrepancy between FA and QA was suggestive of reduced potential for neuroplasticity. Exploratory analyses further indicated that variability in white matter density in the cingulum, an important connection for limbic regions, was associated with a range of problems commonly reported in clinical settings, which may be informative for diagnosis and treatment planning.
Despite a wide range of proposed risk factors and theoretical models, prediction of eating disorder (ED) onset remains poor. This study undertook the first comparison of two machine learning (ML) approaches [penalised logistic regression (LASSO), and prediction rule ensembles (PREs)] to conventional logistic regression (LR) models to enhance prediction of ED onset and differential ED diagnoses from a range of putative risk factors.
Method
Data were part of a European Project and comprised 1402 participants, 642 ED patients [52% with anorexia nervosa (AN) and 40% with bulimia nervosa (BN)] and 760 controls. The Cross-Cultural Risk Factor Questionnaire, which assesses retrospectively a range of sociocultural and psychological ED risk factors occurring before the age of 12 years (46 predictors in total), was used.
Results
All three statistical approaches had satisfactory model accuracy, with an average area under the curve (AUC) of 86% for predicting ED onset and 70% for predicting AN v. BN. Predictive performance was greatest for the two regression methods (LR and LASSO), although the PRE technique relied on fewer predictors with comparable accuracy. The individual risk factors differed depending on the outcome classification (EDs v. non-EDs and AN v. BN).
Conclusions
Even though the conventional LR performed comparably to the ML approaches in terms of predictive accuracy, the ML methods produced more parsimonious predictive models. ML approaches offer a viable way to modify screening practices for ED risk that balance accuracy against participant burden.
Implicit memories like consumption habits and conditioned reactions to drug-related stimuli are operational in addiction and relapse. The affective startle paradigm is an attractive tool for the measurement of the incentive salience of drug-related cues. We tested whether the stronger appetitive valence of drug cues, shown in two recent startle studies in smokers, does persist after prolonged abstinence, and may thus contribute to relapse.
Method:
We examined the auditory startle reflex magnitude of mildly deprived (4-6 hours) heavy smokers (n = 24), former smokers (n = 16, mean abstinence interval 18 months), and non-smokers (n = 24) while they viewed smoking-related scenes or standardized unpleasant, neutral and pleasant control scenes from the International Affective Picture System.
Results:
As expected, non-smokers showed no appetitive reactions toward smoking-cues. In smokers, smoking-cues had both appetitive implicit (startle suppression) and explicit (ratings for valence and craving) motivational effects, resembling those of pleasant scenes and differing from neutral and unpleasant scenes. This effect was more pronounced in smokers who later relapsed after a smoking cessation program, and in smokers consuming less than 20 cigarettes per day. Former smokers, despite reporting no craving and negative reactions to smoking cues, still showed evidence of implicit appetitive valence of these cues.
Conclusions:
Nicotine addiction results in automatic appetitive reactions to drug-cues, which does not vanish after prolonged abstinence and which may thus contribute to relapses. Heavy smoking may result in a progressive internalization of smoking habits and a decline in reactivity towards external smoking-associated cues.
To assess the differences in comorbid lifetime substance use (tobacco, alcohol and drug use) between eating disorder (ED) patients and healthy controls.
Method:
Participants were a consecutive series of 779 ED cases, who had been referred to specialised ED units in five European countries. The ED cases were compared to a balanced control group of 785 healthy individuals. Assessment: Participants completed the Substance Use Subscale of the Cross Cultural Questionnaire (CCQ), a measure of lifetime tobacco, alcohol and drug use. In the control group, also the GHQ-28, the SCID-I interview and the EAT-26 were used.
Results:
ED patients had higher lifetime consumption of tobacco and drugs (p <0.01). The only insignificant result was obtained for alcohol (OR= 1.29; δ =0.157; N.S.) and cannabis use (OR= 1.21; δ = 0.037, N.S.). Significant differences across ED sub diagnoses also emerged for all of the assessed variables (p<0.01), with the BN and AN-BP patients generally presenting the highest prevalence rates. The only exception was detected for alcohol consumption where EDNOS patients demonstrated the highest values (p=0.008). Only a few cultural differences between countries emerged (p<0.05).
Conclusions:
Lifetime tobacco and drug use but not alcohol consumption are more prevalent in ED patients than healthy controls. While alcohol appears to be more common in EDNOS, smoking and drug use are more frequent in patients with bulimic symptomatology. The differential risk observed in patients with bulimic features might be related to differences in temperament or might be the result of increased sensitivity to reward.
To examine whether there is an association between individual and family eating patterns during childhood and early adolescence and the likelihood of developing an eating disorder (ED) later in life.
Method:
Participants were a consecutive series of 879 ED cases from five different European countries. The ED cases were compared to a control group of 785 healthy individuals. Assessment: Participants completed the Early Eating Environmental Subscale of the Cross-Cultural (Environmental) Questionnaire (CCQ), a retrospective measure, which has been developed to detect dimensions associated with EDs in different countries. In the control group, also the GHQ-28, the SCID-I interview and the EAT-26 were used.
Results:
Five individual CatPCA procedures revealed five predetermined dimensions which were labeled: 1.) food as individualization; 2.) control and rules about food; 3.) food as social glue; 4.) healthy eating and 5.) food neglect. Logistic regression analyses indicated that the domains with the strongest effects were: food used as individualization (p=0.001; OR=1.76) and control and rules about food (p=0.001; OR=1.76). Conversely, healthy eating was negatively related to a later ED (p=0.001; OR=0.629). The pattern of associated ED factors was found to very between countries. There was very little difference in early eating behavior on the subtypes of the ED.
Conclusions:
The fragmentation of meals within the family and control and rules about food appears to be linked to the development of a subsequent ED. On the other hand mantaining a structured and balanced diet during infancy seems to protect from a later ED.
The aim of this study was to detect longitudinal differences in white matter brain structures in adults with schizophrenia compared to healthy controls.
Methods
Twenty adult patients with multi-episode schizophrenia under stable antipsychotic medication and twenty-two age- and sex-matched healthy subjects were included in the study. Diffusion Tensor Imaging (DTI) was applied at baseline (t1), after 6weeks (t2) and after 3months (t3) and data processing was done with tract-based spatial statistics (p<0.05, corrected). Two subjects in the schizophrenic sample dropped out at t2 and one healthy subject at t3. Clinical and neuropsychological variables were measured and correlated with the most significant DTI findings.
Results
Compared with healthy age- and sex-matched controls schizophrenic patients showed widespread decreases in mean fractional anisotropy values (p<0.05, corrected). The most obvious FA decrease in the long-term was found in the anterior part of the corpus callosum (p<0.005, corrected), the left temporal lobe (p<0.004, corr.) and the mid-cingulate gyrus bilateral (p<0.004, corr.). Correlations to demographic variables, clinical rating scales (PANSS, CGI and GAF), verbal learning and memory and working memory will be presented.
Conclusion
Magnetic resonance imaging was able to detect altered structural connectivity in patients with multi-episode schizophrenia in a longitudinal design.
Vertigo and anxiety are frequent symptoms in both psychiatric and vertigo patients, especially in those with phobic postural vertigo (PPV). The aim of this study was the investigation of anxiety-associated functional responses in PPV patients compared to healthy controls. For that purpose cholecystokinin tetrapeptide (CCK-4), a valid model to experimentally induce anxiety symptoms, was used.
15 PPV patients and 15 matched healthy controls underwent challenges with CCK-4. During the paradigm, participants did not know the exact time point of the injection in order to separate the anticipatory and CCK-4 induced anxiety. The panic symptom scale score was assessed before and after the injection.
During anticipatory anxiety healthy controls showed functional responses mainly in fronto-temporal regions. Patients suffering from PPV showed pronounced BOLD responses in the (ventral) anterior cingulate cortex (ACC), dorsolateral prefrontal cortex, orbitofrontal cortex and precuneus. In healthy subjects, CCK-4 induced anxiety was accompanied by activations in the medial and inferior frontal cortex. In PPV, the CCK-4 injection led to increased activities particularly in the ACC, the cuneus, the cerebellum, the amygdala and fronto-temporal regions.
Given the fact of increased neuronal responses in emotion-related brain areas in patients with anxiety disorders these findings could provide evidence for common aspects of phobic postural vertigo and anxiety disorders.
Identifying the transmission sources and reservoirs of Streptococcus pneumoniae (SP) is a long-standing question for pneumococcal epidemiology, transmission dynamics, and vaccine policy. Here we use serotype to identify SP transmission and examine acquisitions (in the same household, local community, and county, or of unidentified origin) in a longitudinal cohort of children and adults from the Navajo Nation and the White Mountain Apache American Indian Tribes. We found that adults acquire SP relatively more in the household than other age groups, and children 2–8 years old typically acquire in their own or surrounding communities. Age-specific transmission probability matrices show that transmissions within household were mostly seen from older to younger siblings. Outside the household, children most often transmit to other children in the same age group, showing age-assortative mixing behavior. We find toddlers and older children to be most involved in SP transmission and acquisition, indicating their role as key drivers of SP epidemiology. Although infants have high carriage prevalence, they do not play a central role in transmission of SP compared with toddlers and older children. Our results are relevant to inform alternative pneumococcal conjugate vaccine dosing strategies and analytic efforts to inform optimization of vaccine programs, as well as assessing the transmission dynamics of pathogens transmitted by close contact in general.
Malaria elimination is on global agendas following successful transmission reductions. Nevertheless moving from low to zero transmission is challenging. South Africa has an elimination target of 2018, which may or may not be realised in its hypoendemic areas.
Methods
The Agincourt Health and Demographic Surveillance System has monitored population health in north-eastern South Africa since 1992. Malaria deaths were analysed against individual factors, socioeconomic status, labour migration and weather over a 21-year period, eliciting trends over time and associations with covariates.
Results
Of 13 251 registered deaths over 1.58 million person-years, 1.2% were attributed to malaria. Malaria mortality rates increased from 1992 to 2013, while mean daily maximum temperature rose by 1.5 °C. Travel to endemic Mozambique became easier, and malaria mortality increased in higher socioeconomic groups. Overall, malaria mortality was significantly associated with age, socioeconomic status, labour migration and employment, yearly rainfall and higher rainfall/temperature shortly before death.
Conclusions
Malaria persists as a small but important cause of death in this semi-rural South African population. Detailed longitudinal population data were crucial for these analyses. The findings highlight practical political, socioeconomic and environmental difficulties that may also be encountered elsewhere in moving from low-transmission scenarios to malaria elimination.
Africa is experiencing a rapid increase in adult obesity and associated cardiometabolic diseases (CMDs). The H3Africa AWI-Gen Collaborative Centre was established to examine genomic and environmental factors that influence body composition, body fat distribution and CMD risk, with the aim to provide insights towards effective treatment and intervention strategies. It provides a research platform of over 10 500 participants, 40–60 years old, from Burkina Faso, Ghana, Kenya and South Africa. Following a process that involved community engagement, training of project staff and participant informed consent, participants were administered detailed questionnaires, anthropometric measurements were taken and biospecimens collected. This generated a wealth of demographic, health history, environmental, behavioural and biomarker data. The H3Africa SNP array will be used for genome-wide association studies. AWI-Gen is building capacity to perform large epidemiological, genomic and epigenomic studies across several African counties and strives to become a valuable resource for research collaborations in Africa.
Within the framework of a major European co-operative research project on rotorcraft aerodynamics and acoustics (Helishape), a parametric model rotor test was conducted in the open test section of the DNW using DLR's MWM test rig, and a highly instrumented model of a fully articulated ECF rotor equipped with blades of advanced design with two exchangeable blade tips. One set of blade tips (7A) was rectangular, while the other (7AD1) was a swept-back parabolic-anhedral shape. The objectives of this experimental research were to evaluate noise reduction techniques (conceptionally by variation of rotor speed, dedicated tip shapes and advanced aerofoils, as well as operationally, by identifying low noise, BVI-minimising, descent procedures) and to validate the partners’ aerodynamic and aeroacoustic codes. A comprehensive set of simultaneous acoustic and aerodynamic blade surface pressure data and blade dynamic and performance data was measured. In addition, valuable information on the tip-vortex geometry and blade-vortex miss distance was obtained by LLS flow visualisation. The experimental equipment, the test procedures, and the test matrix are briefly described. A survey of the main results is presented and the trends of the most important parameter variations for both rotors are discussed.
Altered microbial communities are thought to play an important role in eosinophilic oesophagitis, an allergic inflammatory condition of the oesophagus. Identification of the majority of organisms present in human-associated microbial communities is feasible with the advent of high throughput sequencing technology. However, these data consist of non-negative, highly skewed sequence counts with a large proportion of zeros. In addition, hierarchical study designs are often performed with repeated measurements or multiple samples collected from the same subject, thus requiring approaches to account for within-subject variation, yet only a small number of microbiota studies have applied hierarchical regression models. In this paper, we describe and illustrate the use of a hierarchical regression-based approach to evaluate multiple factors for a small number of organisms individually. More specifically, the zero-inflated negative binomial mixed model with random effects in both the count and zero-inflated parts is applied to evaluate associations with disease state while adjusting for potential confounders for two organisms of interest from a study of human microbiota sequence data in oesophagitis.
Whether late-onset depression is a risk factor for or a prodrome of dementia remains unclear. We investigated the impact of depressive symptoms and early- v. late-onset depression on subsequent dementia in a cohort of elderly general-practitioner patients (n = 2663, mean age = 81.2 years).
Method
Risk for subsequent dementia was estimated over three follow-ups (each 18 months apart) depending on history of depression, particularly age of depression onset, and current depressive symptoms using proportional hazard models. We also examined the additive prediction of incident dementia by depression beyond cognitive impairment.
Results
An increase of dementia risk for higher age cut-offs of late-onset depression was found. In analyses controlling for age, sex, education, and apolipoprotein E4 genotype, we found that very late-onset depression (aged ⩾70 years) and current depressive symptoms separately predicted all-cause dementia. Combined very late-onset depression with current depressive symptoms was specifically predictive for later Alzheimer's disease (AD; adjusted hazard ratio 5.48, 95% confidence interval 2.41–12.46, p < 0.001). This association was still significant after controlling for cognitive measures, but further analyses suggested that it was mediated by subjective memory impairment with worries.
Conclusions
Depression might be a prodrome of AD but not of dementia of other aetiology as very late-onset depression in combination with current depressive symptoms, possibly emerging as a consequence of subjectively perceived worrisome cognitive deterioration, was most predictive. As depression parameters and subjective memory impairment predicted AD independently of objective cognition, clinicians should take this into account.
Young people with self-experienced cognitive thought and perception deficits (basic symptoms) may present with an early initial prodromal state (EIPS) of psychosis in which most of the disability and neurobiological deficits of schizophrenia have not yet occurred.
Aims
To investigate the effects of an integrated psychological intervention (IPI), combining individual cognitive–behavioural therapy, group skills training, cognitive remediation and multifamily psychoeducation, on the prevention of psychosis in the EIPS.
Method
A randomised controlled, multicentre, parallel group trial of 12 months of IPI v. supportive counselling (trial registration number: NCT00204087). Primary outcome was progression to psychosis at 12- and 24-month follow-up.
Results
A total of 128 help-seeking out-patients in an EIPS were randomised. Integrated psychological intervention was superior to supportive counselling in preventing progression to psychosis at 12-month follow-up (3.2% v. 16.9%; P = 0.008) and at 24-month follow-up (6.3% v. 20.0%; P = 0.019).
Conclusions
Integrated psychological intervention appears effective in delaying the onset of psychosis over a 24-month time period in people in an EIPS.
With modern undulators generating light of an arbitrary polarization state, experiments exploiting this feature in the soft X-ray region are becoming increasingly widespread. Circularly polarized light in the soft X-ray region is of particular interest to investigate of magnetic metals such as Fe, Co and Ni, and the rare earths. A versatile multilayer polarimeter has been designed and developed to characterize the polarization state of the soft X-ray beam. A W/B4C multilayer transmission phase retarder and reflection analyser has been used for polarimetry measurements on the beamline (I06) at Diamond Light Source. The design details of the polarimeter and preliminary polarimetry results are presented.