Functional and structural brain network correlates of visual hallucinations in Lewy body dementia.

Visual hallucinations are a common feature of Lewy body dementia. Previous studies have shown that visual hallucinations are highly specific in differentiating Lewy body dementia from Alzheimer's disease dementia and Alzheimer-Lewy body mixed pathology cases. Computational models propose that impairment of visual and attentional networks is aetiologically key to the manifestation of visual hallucinations symptomatology. However, there is still a lack of experimental evidence on functional and structural brain network abnormalities associated with visual hallucinations in Lewy body dementia. We used EEG source localization and network based statistics to assess differential topographical patterns in Lewy body dementia between 25 participants with visual hallucinations and 17 participants without hallucinations. Diffusion tensor imaging was used to assess structural connectivity between thalamus, basal forebrain and cortical regions belonging to the functionally affected network component in the hallucinating group, as assessed with network based statistics. The number of white matter streamlines within the cortex and between subcortical and cortical regions was compared between hallucinating and not hallucinating groups and correlated with average EEG source connectivity of the affected subnetwork. Moreover, modular organization of the EEG source network was obtained, compared between groups and tested for correlation with structural connectivity. Network analysis showed that compared to non-hallucinating patients, those with hallucinations feature consistent weakened connectivity within the visual ventral network, and between this network and default mode and ventral attentional networks, but not between or within attentional networks. The occipital lobe was the most functionally disconnected region. Structural analysis yielded significantly affected white matter streamlines connecting the cortical regions to the nucleus basalis of Meynert and the thalamus in hallucinating compared to not hallucinating patients. The number of streamlines in the tract between the basal forebrain and the cortex correlated with cortical functional connectivity in non-hallucinating patients, while a correlation emerged for the white matter streamlines connecting the functionally affected cortical regions in the hallucinating group. This study proposes, for the first time, differential functional networks between hallucinating and not hallucinating Lewy body dementia patients, and provides empirical evidence for existing models of visual hallucinations. Specifically, the outcome of the present study shows that the hallucinating condition is associated with functional network segregation in Lewy body dementia and supports the involvement of the cholinergic system as proposed in the current literature.

A Tailored Decision Aid Improves Understanding of Lung Cancer Screening in People With HIV.

BACKGROUND: People with HIV are at increased risk for lung cancer and multimorbidity, complicating the balance of risks and benefits of lung cancer screening. We previously adapted Decision Precision (screenlc.com) to guide shared decision-making for lung cancer screening in people with HIV. RESEARCH QUESTION: Does an HIV-adapted and personally tailored decision aid improve shared decision-making regarding lung cancer screening in people with HIV as measured by knowledge, decisional conflict, and acceptability? STUDY DESIGN AND METHODS: This was a single-arm pilot trial of the decision aid in 40 participants with HIV eligible for lung cancer screening. The decision aid included personalized screening recommendations and HIV-specific, 5-year risk estimates of lung cancer and all-cause mortality. Participants reviewed the decision aid at shared decision-making visits and completed previsit and postvisit surveys with measures of knowledge about lung cancer screening, acceptability, and decisional conflict. RESULTS: The 40 enrolled participants were a median 62 years old, 60% were currently smoking, and they had median 5-year risks of lung cancer and all-cause mortality of 2.0% (IQR, 1.4%-3.3%) and 4.1% (IQR, 3.3%-7.9%), respectively. Personalized recommendations included "Encourage Screening" for 53% of participants and "Preference Sensitive" recommendations for the remainder. Participants showed improvement in 2 validated knowledge measures with relative improvement of 60% (P < 0.001) on the 12-question lung cancer screening knowledge test and 27% (P < .001) on the 7-question lung cancer screening knowledge score, with significant improvement on questions regarding false-positive and false-negative findings, incidental findings, lung cancer-specific mortality benefit, and the possible harms of screening. Participants reported low scores on the decisional conflict scale (median score, 0; IQR, 0-5) and high acceptability. Ninety percent of patients ultimately underwent screening within 1 month of the visit. INTERPRETATION: This HIV-adapted and personally tailored decision aid improved participants' knowledge of risks, benefits, and characteristics of screening with low decisional conflict and high acceptability. This decision aid can enable high-quality shared decision-making in this high-risk population. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT04682301; URL: www. CLINICALTRIALS: gov.

Spread of yellow fever virus outbreak in Angola and the Democratic Republic of the Congo 2015-16: a modelling study.

BACKGROUND: Since late 2015, an epidemic of yellow fever has caused more than 7334 suspected cases in Angola and the Democratic Republic of the Congo, including 393 deaths. We sought to understand the spatial spread of this outbreak to optimise the use of the limited available vaccine stock. METHODS: We jointly analysed datasets describing the epidemic of yellow fever, vector suitability, human demography, and mobility in central Africa to understand and predict the spread of yellow fever virus. We used a standard logistic model to infer the district-specific yellow fever virus infection risk during the course of the epidemic in the region. FINDINGS: The early spread of yellow fever virus was characterised by fast exponential growth (doubling time of 5-7 days) and fast spatial expansion (49 districts reported cases after only 3 months) from Luanda, the capital of Angola. Early invasion was positively correlated with high population density (Pearson's r 0·52, 95% CI 0·34-0·66). The further away locations were from Luanda, the later the date of invasion (Pearson's r 0·60, 95% CI 0·52-0·66). In a Cox model, we noted that districts with higher population densities also had higher risks of sustained transmission (the hazard ratio for cases ceasing was 0·74, 95% CI 0·13-0·92 per log-unit increase in the population size of a district). A model that captured human mobility and vector suitability successfully discriminated districts with high risk of invasion from others with a lower risk (area under the curve 0·94, 95% CI 0·92-0·97). If at the start of the epidemic, sufficient vaccines had been available to target 50 out of 313 districts in the area, our model would have correctly identified 27 (84%) of the 32 districts that were eventually affected. INTERPRETATION: Our findings show the contributions of ecological and demographic factors to the ongoing spread of the yellow fever outbreak and provide estimates of the areas that could be prioritised for vaccination, although other constraints such as vaccine supply and delivery need to be accounted for before such insights can be translated into policy. FUNDING: Wellcome Trust.