Brain network connectivity underlying neuropsychiatric symptoms in prodromal Lewy body dementia.

Neuropsychiatric symptoms (NPS) are prevalent, emerge early, and are associated with poorer outcomes in Lewy body dementia (LBD). Research suggests NPS may reflect LBD-related dysfunction in distributed neuronal networks. This study investigated NPS neural correlates in prodromal LBD using resting-state functional MRI. Fifty-seven participants were included with mild cognitive impairment (MCI) with Lewy bodies (MCILB, n=28) or Parkinson’s disease (PD-MCI, n=29). Functional MRI assessed connectivity within five resting-state networks: primary visual, dorsal attention, salience, limbic, and default mode networks. NPS were measured using the Neuropsychiatric Inventory. Principal component analyses identified three neuropsychiatric factors: affective disorder (apathy, depression), psychosis (delusions, hallucinations) and anxiety. Seed-to-voxel connectivity maps were analysed to determine associations between NPS and network connectivity. In PD-MCI, affective symptoms and anxiety were associated with greater connectivity between limbic orbitofrontal cortex and default mode areas, including medial prefrontal cortex, subgenual cingulate and precuneus, and weaker connectivity between limbic orbitofrontal cortex and the brainstem and between the salience network and medial prefrontal cortex (all pFWE<0.001). Psychosis severity in PD-MCI correlated with connectivity across multiple networks (all pFWE<0.001). In MCI-LB, no significant correlations were found between NPS severity and network connectivity. However, participants with anxiety demonstrated a trend towards greater connectivity within medial prefrontal areas than those without (pFWE=0.046). Altered connectivity within and between networks associated with mood disorders may explain affective and anxiety symptoms in PD-MCI. Neural correlates of NPS in MCI-LB, however, remain unclear, highlighting the need for research in larger, more diverse LBD populations to identify symptomatic treatment target

The dynamics of nasopharyngeal streptococcus pneumoniae carriage among rural Gambian mother-infant pairs

<p>Abstract</p> <p>Background</p> <p><it>Streptococcus pneumoniae </it>is an important cause of community acquired pneumonia, sepsis, meningitis and otitis media globally and has been incriminated as a major cause of serious childhood bacterial infections in The Gambia. Better understanding of the dynamics of transmission and carriage will inform control strategies.</p> <p>Methods</p> <p>This study was conducted among 196 mother-infant pairs recruited at birth from six villages in the West Kiang region of The Gambia. Nasopharyngeal swabs were collected from mother-infant pairs at birth (within 12 hours of delivery), 2, 5 and 12 months. Standard techniques of culture were used to identify carriage and serotype <it>S. pneumoniae</it>.</p> <p>Results</p> <p>Of 46 serotypes identified, the 6 most common, 6A, 6B, 14, 15, 19F and 23F, accounted for 67.3% of the isolates from infants. Carriage of any serotype among infants rose from 1.5% at birth to plateau at approximately 80% by 2 m (prevalence at 2 m = 77%; 5 m = 86%; 12 m = 78%). Likewise, maternal carriage almost doubled in the first 2 months post-partum and remained elevated for the next 10 m (prevalence at birth = 13%; 2 m = 24%; 5 m = 22%; 12 m = 21%). Carriage was significantly seasonal in both infants and mothers with a peak in December and lowest transmission in August. The total number of different serotypes we isolated from each infant varied and less than would be expected had the serotypes assorted independently. In contrast, this variability was much as expected among mothers. The half-life of a serotype colony was estimated to be 1.90 m (CI_95%: 1.66-2.21) in infants and 0.75 m (CI_95%: 0.55-1.19) in mothers. While the odds for a serotype to be isolated from an infant increased by 9-fold if it had also been isolated from the mother, the population attributable fraction (PAF) of pneumococcal carriage in infants due to maternal carriage was only 9.5%. Some marked differences in dynamics were observed between vaccine and non-vaccine serotypes.</p> <p>Conclusions</p> <p>Colonisation of the nasopharynx in Gambian infants by <it>S. pneumoniae </it>is rapid and highly dynamic. Immunity or inter-serotype competition may play a role in the dynamics. Reducing mother-infant transmission would have a minimal effect on infant carriage.</p

Impact of referral bias on clinical and epidemiological studies of Alzheimer's disease

We used the resources of the Rochester Epidemiology Project to compare sociodemographic and clinical characteristics in three groups of Alzheimer's disease patients. The first group included incidence cases occurring among residents of Rochester, Minnesota (population-based series; n = 241). The second group was a sample of patients referred to the Mayo Clinic from the remainder of Minnesota and the four surrounding states (n = 58); the third was a sample referred from the remainder of the United States (n = 94). Patients from Rochester were more frequently women, less highly educated, less commonly white collar workers, more frequently institutionalized, less frequently married, and more often lived alone than those in the two referral groups; Patients from Rochester also had a more advanced age of onset of dementia. For occupation, education, and living arrangement, the differences across groups increased with increasing distance of referral. Clinical and epidemiological studies based on patients referred from primary to secondary or tertiary care centers may suffer from severe selection bias

INCIDENCE AND PREVALENCE OF HUNTINGTONS-DISEASE IN OLMSTED COUNTY, MINNESOTA (1950 THROUGH 1989)

Objective: To calculate average annual incidence rates for Huntington's disease (HD) from 1950 through 1989 and to estimate prevalence rates of the disease for January 1, 1960, and January 1, 1990