Childhood cognitive ability accounts for associations between cognitive ability and brain cortical thickness in old age

Associations between brain cortical tissue volume and cognitive function in old age are frequently interpreted as suggesting that preservation of cortical tissue is the foundation of successful cognitive aging. However, this association could also, in part, reflect a lifelong association between cognitive ability and cortical tissue. We analyzed data on 588 subjects from the Lothian Birth Cohort 1936 who had intelligence quotient (IQ) scores from the same cognitive test available at both 11 and 70 years of age as well as high-resolution brain magnetic resonance imaging data obtained at approximately 73 years of age. Cortical thickness was estimated at 81 924 sampling points across the cortex for each subject using an automated pipeline. Multiple regression was used to assess associations between cortical thickness and the IQ measures at 11 and 70 years. Childhood IQ accounted for more than two-third of the association between IQ at 70 years and cortical thickness measured at age 73 years. This warns against ascribing a causal interpretation to the association between cognitive ability and cortical tissue in old age based on assumptions about, and exclusive reference to, the aging process and any associated disease. Without early-life measures of cognitive ability, it would have been tempting to conclude that preservation of cortical thickness in old age is a foundation for successful cognitive aging when, instead, it is a lifelong association. This being said, results should not be construed as meaning that all studies on aging require direct measures of childhood IQ, but as suggesting that proxy measures of prior cognitive function can be useful to take into consideration.

Morphologic, distributional, volumetric, and intensity characterization of periventricular hyperintensities

BACKGROUND AND PURPOSE

White matter hyperintensities are characteristic of old age and identifiable on FLAIR and T2-weighted MR imaging. They are typically separated into periventricular or deep categories. It is unclear whether the innermost segment of periventricular white matter hyperintensities is truly abnormal or is imaging artifacts.

MATERIALS AND METHODS

We used FLAIR MR imaging from 665 community-dwelling subjects 72-73 years of age without dementia. Periventricular white matter hyperintensities were visually allocated into 4 categories: 1) thin white line; 2) thick rim; 3) penetrating toward or confluent with deep white matter hyperintensities; and 4) diffuse ill-defined, labeled as "subtle extended periventricular white matter hyperintensities." We measured the maximum intensity and width of the periventricular white matter hyperintensities, mapped all white matter hyperintensities in 3D, and investigated associations between each category and hypertension, stroke, diabetes, hypercholesterolemia, cardiovascular disease, and total white matter hyperintensity volume.

RESULTS

The intensity patterns and morphologic features were different for each periventricular white matter hyperintensity category. Both the widths (r = 0.61, P < .001) and intensities (r = 0.51, P < .001) correlated with total white matter hyperintensity volume and with each other (r = 0.55, P < .001) for all categories with the exception of subtle extended periventricular white matter hyperintensities, largely characterized by evidence of erratic, ill-defined, and fragmented pale white matter hyperintensities (width: r = 0.02, P = .11; intensity: r = 0.02, P = .84). The prevalence of hypertension, hypercholesterolemia, and neuroradiologic evidence of stroke increased from periventricular white matter hyperintensity categories 1 to 3. The mean periventricular white matter hyperintensity width was significantly larger in subjects with hypertension (mean difference = 0.5 mm, P = .029) or evidence of stroke (mean difference = 1 mm, P < .001). 3D mapping revealed that periventricular white matter hyperintensities were discontinuous with deep white matter hyperintensities in all categories, except only in particular regions in brains with category 3.

CONCLUSIONS

Periventricular white matter hyperintensity intensity levels, distribution, and association with risk factors and disease suggest that in old age, these are true tissue abnormalities and therefore should not be dismissed as artifacts. Dichotomizing periventricular and deep white matter hyperintensities by continuity from the ventricle edge toward the deep white matter is possible.

Neuroticism, depressive symptoms and white-matter integrity in the Lothian Birth Cohort 1936

BACKGROUND

Clinical depression is associated with reductions in white-matter integrity in several long tracts of the brain. The extent to which these findings are localized or related to depressive symptoms or personality traits linked to disease risk remains unclear. Method Members of the Lothian Birth Cohort 1936 (LBC936) were assessed in two waves at mean ages of 70 and 73 years. At wave 1, they underwent assessments of depressive symptoms and the personality traits of neuroticism and extraversion. Brain diffusion magnetic resonance imaging (MRI) data were obtained at the second wave and mood assessments were repeated. We tested whether depressive symptoms were related to reduced white-matter tract fractional anisotropy (FA), a measure of integrity, and then examined whether high neuroticism or low extraversion mediated this relationship.

RESULTS

Six hundred and sixty-eight participants provided useable data. Bilateral uncinate fasciculus FA was significantly negatively associated with depressive symptoms at both waves (standardized β=0.12-0.16). Higher neuroticism and lower extraversion were also significantly associated with lower uncinate FA bilaterally (standardized β=0.09-0.15) and significantly mediated the relationship between FA and depressive symptoms.

CONCLUSIONS

Trait liability to depression and depressive symptoms are associated with reduced structural connectivity in tracts connecting the prefrontal cortex with the amygdala and anterior temporal cortex. These effects suggest that frontotemporal disconnection is linked to the etiology of depression, in part through personality trait differences.

Brain white matter tract integrity as a neural foundation for general intelligence

General intelligence is a robust predictor of important life outcomes, including educational and occupational attainment, successfully managing everyday life situations, good health and longevity. Some neuronal correlates of intelligence have been discovered, mainly indicating that larger cortices in widespread parieto-frontal brain networks and efficient neuronal information processing support higher intelligence. However, there is a lack of established associations between general intelligence and any basic structural brain parameters that have a clear functional meaning. Here, we provide evidence that lower brain-wide white matter tract integrity exerts a substantial negative effect on general intelligence through reduced information-processing speed. Structural brain magnetic resonance imaging scans were acquired from 420 older adults in their early 70s. Using quantitative tractography, we measured fractional anisotropy and two white matter integrity biomarkers that are novel to the study of intelligence: longitudinal relaxation time (T1) and magnetisation transfer ratio. Substantial correlations among 12 major white matter tracts studied allowed the extraction of three general factors of biomarker-specific brain-wide white matter tract integrity. Each was independently associated with general intelligence, together explaining 10% of the variance, and their effect was completely mediated by information-processing speed. Unlike most previously established neurostructural correlates of intelligence, these findings suggest a functionally plausible model of intelligence, where structurally intact axonal fibres across the brain provide the neuroanatomical infrastructure for fast information processing within widespread brain networks, supporting general intelligence.

An evaluation of the Sebia capillarys Neonat Haemoglobin FAST™ system for routine newborn screening for sickle cell disease

The West Midlands Newborn Screening Laboratory (NBSL) at Birmingham Children's Hospital (BCH), UK, screens approximately 71 000 babies per annum using the Bio-Rad automated VARIANT™ nbs (Vnbs) high-pressure liquid chromatograph (HPLC). Any abnormal haemoglobins detected, including S, C, D-Punjab, E and O-Arab as directed by the NHS Sickle Cell and Thalassaemia Screening Programme (NHS Sickle Cell and Thalassaemia Screening Programme Website, http://sct.screening.nhs.uk), are then confirmed using Resolve® isoelectric electric focusing (IEF) kits supplied by Perkin-Elmer. The Sebia capillarys Neonat Haemoglobin FAST™ system was evaluated as a possible replacement for the first- or second-line methods used. Both the Sebia and Bio-Rad methods were compared using anonymized blood spots with known haemoglobin patterns. These results were then confirmed when necessary by IEF. The Sebia-recommended sample preparation was also modified to enable testing to be more comparable with our current processes. Percentages of haemoglobins calculated from integration of areas under the peaks were compared between the Bio-Rad Vnbs HPLC and Sebia capillarys Neonat Haemoglobin FAST™ system. Of the 347 blood spots tested by both HPLC and capillary electrophoresis, there were no significant differences. The Sebia capillarys Neonat Haemoglobin FAST™ system can be used to successfully screen newborns for sickle cell disease in blood spots collected for newborn screening with full positive sample identification and traceability.

Images of the terminal ileum are more convincing than cecal images for verifying the extent of colonoscopy

BACKGROUND AND STUDY AIMS

Independent verification of colonoscopy completion is important for quality assurance. Cecal photographs aimed at showing key landmarks, including the ileocecal valve (ICV) and appendiceal orifice are the currently recommended standard, but are often perceived as unreliable. Images of the terminal ileum demonstrating villi may provide more robust evidence of completion. We sought to prospectively evaluate the ease of routine intubation of the terminal ileum and to compare the effectiveness of terminal ileum and cecal photographs in convincing independent reviewers that total colonoscopy had been accomplished.

PATIENTS AND METHODS

A prospective, observational study evaluated 216 consecutively completed colonoscopies performed in routine clinical practice. Cecal and terminal ileum photographs were evaluated and scored by independent reviewers. Frequency of terminal ileum intubation, time required, and safety parameters were recorded.

RESULTS

The terminal ileum was intubated and photographed in 188/216 (87%) of cases. Median time taken to intubate, or attempt to intubate the terminal ileum was 1 min 24 s, and was achieved without complications or requirement for additional sedation. Terminal ileum images were significantly more likely to be considered convincing than cecal images ( P<0.0001 for all reviewers). There was excellent interobserver agreement amongst the opinion of reviewers regarding terminal ileum photographs (kappa=0.91).

CONCLUSION

Terminal ileum intubation is achievable rapidly and safely in the majority of patients undergoing colonoscopy. Terminal ileum images provide more convincing evidence of complete examination of the colon than cecal images, even when attempts to capture images specifically of the ICV and appendiceal orifice are made.

General practice out-of-hours service in Ireland provides a new source of syndromic surveillance data on influenza

The use of routinely available electronic sources of healthcare data on the spread of influenza has the potential to enhance current surveillance activities. This study aimed to develop a method for identifying influenza-related records from general practitioner (GP) out-of-hours (OOH) services in Ireland. Data from one such service were interrogated for keywords relating to influenza-like illness (ILI) and a proxy measure of influenza activity in the community setting was developed. Comparison of this syndromic surveillance measure with national data on ILI consultation rates demonstrated a statistically significant temporal correlation. In five out of six influenza seasons investigated, peaks in the GP OOH influenza-related calls appeared at least one week ahead of peaks in the national ILI consultation rates. The method described in this paper has been extended to nine OOH services in Ireland (covering 70% of the Irish population) to provide weekly figures on self-reported illness for influenza in the community and its data have been incorporated into the national weekly influenza reports produced by the Health Protection Surveillance Centre. These data should provide early warnings of both seasonal and pandemic influenza in Ireland.

General practice out-of-hours service in Ireland provides a new source of syndromic surveillance data on influenza

The use of routinely available electronic sources of healthcare data on the spread of influenza has the potential to enhance current surveillance activities. This study aimed to develop a method for identifying influenza-related records from general practitioner(GP) out-of-hours (OOH) services in Ireland. Data from one such service were interrogated for keywords relating to influenza-like illness (ILI) and a proxy measure of influenza activity in the community setting was developed. Comparison of this syndromic surveillance measure with national data on ILI consultation rates demonstrated a statistically significant temporal correlation.In five out of six influenza seasons investigated,peaks in the GP OOH influenza-related calls appeared at least one week ahead of peaks in the national ILI consultation rates. The method described in this paper has been extended to nine OOH services in Ireland (covering 70% of the Irish population) to provide weekly figures on self-reported illness for influenza in the community and its data have been incorporated into the national weekly influenza reports produced by the Health Protection Surveillance Centre. These data should provide early warnings of both seasonal and pandemic influenza in Ireland.