Cortical growth from infancy to adolescence in preterm and term-born children.

Early life experiences can exert a significant influence on cortical and cognitive development. Very preterm birth exposes infants to several adverse environmental factors during hospital admission, which affect cortical architecture. However, the subsequent consequence of very preterm birth on cortical growth from infancy to adolescence has never been defined; despite knowledge of critical periods during childhood for establishment of cortical networks. Our aims were to: chart typical longitudinal cortical development and sex differences in cortical development from birth to adolescence in healthy term-born children; estimate differences in cortical development between children born at term and very preterm; and estimate differences in cortical development between children with normal and impaired cognition in adolescence. This longitudinal cohort study included children born at term (≥37 weeks' gestation) and very preterm (<30 weeks' gestation) with MRI scans at ages 0, 7 and 13 years (n = 66 term-born participants comprising 34 with one scan, 18 with two scans and 14 with three scans; n = 201 very preterm participants comprising 56 with one scan, 88 with two scans and 57 with three scans). Cognitive assessments were performed at age 13 years. Cortical surface reconstruction and parcellation were performed with state-of-the-art, equivalent MRI analysis pipelines for all time points, resulting in longitudinal cortical volume, surface area and thickness measurements for 62 cortical regions. Developmental trajectories for each region were modelled in term-born children, contrasted between children born at term and very preterm, and contrasted between all children with normal and impaired cognition. In typically developing term-born children, we documented anticipated patterns of rapidly increasing cortical volume, area and thickness in early childhood, followed by more subtle changes in later childhood, with smaller cortical size in females than males. In contrast, children born very preterm exhibited increasingly reduced cortical volumes, relative to term-born children, particularly during ages 0-7 years in temporal cortical regions. This reduction in cortical volume in children born very preterm was largely driven by increasingly reduced cortical thickness rather than area. This resulted in amplified cortical volume and thickness reductions by age 13 years in individuals born very preterm. Alterations in cortical thickness development were found in children with impaired language and memory. This study shows that the neurobiological impact of very preterm birth on cortical growth is amplified from infancy to adolescence. These data further inform the long-lasting impact on cortical development from very preterm birth, providing broader insights into neurodevelopmental consequences of early life experiences.

Interactions between age, sex and visceral adipose tissue on brain ageing.

AIM: To examine the associations between visceral adipose tissue (VAT) and brain structural measures at midlife and explore how these associations may be affected by age, sex and cardiometabolic factors. METHODS: We used abdominal and brain magnetic resonance imaging data from a population-based cohort of people at midlife in the UK Biobank. Regression modelling was applied to study associations of VAT volume with total brain volume (TBV), grey matter volume (GMV), white matter volume, white matter hyperintensity volume (WMHV) and total hippocampal volume (THV), and whether these associations were altered by age, sex or cardiometabolic factors. RESULTS: Complete data were available for 17 377 participants (mean age 63 years, standard deviation = 12, 53% female). Greater VAT was associated with lower TBV, GMV and THV (P < .001). We found an interaction between VAT and sex on TBV (P < .001), such that the negative association of VAT with TBV was greater in men (ß = -2.89, 95% confidence interval [CI] -2.32 to -10.15) than in women (ß = -1.32, 95% CI -0.49 to -3.14), with similar findings for GMV. We also found an interaction between VAT and age (but not sex) on WMHV (P < .001). The addition of other cardiometabolic factors or measures of physical activity resulted in little change to the models. CONCLUSIONS: VAT volume is associated with poorer brain health in midlife and this relationship is greatest in men and those at younger ages.

Using a multi-stakeholder co-design process to develop a health service organisation-wide patient reported outcome measure collection system.

PURPOSE: Limited examples exist of successful Patient Reported Outcome Measure (PROM) implementation across an entire healthcare organisation. The aim of this study was to use a multi-stakeholder co-design process to develop a PROM collection system, which will inform implementation of routine collection of PROMs across an entire healthcare organisation. METHODS: Co-design comprised semi-structured interviews with clinicians (n = 11) and workshops/surveys with consumers (n = 320). The interview guide with clinicians focused on their experience using PROMs, preferences for using PROMs, and facilitators/barriers to using PROMs. Co-design activities specific to consumers focused on: (1) how PROMs will be administered (mode), (2) when PROMs will be administered (timing), (3) who will assist with PROMs collection, and (4) how long a PROM will take to complete. Data were analysed using a manifest qualitative content analysis approach. RESULTS: Core elements identified during the co-design process included: PROMs collection should be consumer-led and administered by someone other than a clinician; collection at discharge from the healthcare organisation and at 3-6 months post discharge would be most suitable for supporting comprehensive assessment; PROMs should be administered using a variety of modes to accommodate the diversity of consumer preferences, with electronic as the default; and the time taken to complete PROMs should be no longer than 5-10 min. CONCLUSION: This study provides new information on the co-design of a healthcare organisation-wide PROM collection system. Implementing a clinician and patient informed strategy for PROMs collection, that meets their preferences across multiple domains, should address known barriers to routine collection.

Healthcare consumer acceptability of routine use of the EQ-5D-5L in clinical care: a cross-sectional survey.

PURPOSE: Patient reported outcome measures, such as the EQ-5D-5L, provide a measure of self-perceived health status or health-related quality of life. Understanding the consumer acceptability of a patient reported outcome measure can help to decide about its implementation across a healthcare organisation and possibly increase the likelihood of its use in clinical care. This study established the acceptability of the EQ-5D-5L from the perspective of clients receiving healthcare, and determined if acceptability varied by client sub-types. METHODS: A cross-sectional survey explored clients' experience of the EQ-5D-5L. Eligible clients were aged ≥ 18 years and completed the EQ-5D-5L on admission and discharge to one of two multi-disciplinary community health services. Likert scale items explored acceptability, and open-ended questions determined if the EQ-5D-5L reflects experience of illness. Associations between acceptability and client characteristics were established using χ2 test. Open-ended questions were analysed using content analysis. RESULTS: Most of the 304 clients (mean age 70 years, SD 16) agreed that the EQ-5D-5L: was easy to use/understand (n = 301, 99%) and useful (n = 289, 95%); improved communication with their therapist (n = 275, 90%); and made them feel more in control of their health (n = 276, 91%). Most clients also agreed that they wished to continue using the EQ-5D-5L (n = 285, 93%). Clients aged ≥ 60 years reported lower acceptability. Clients noted that the EQ-5D-5L did not capture experience of illness related to fatigue, balance/falls, cognition, and sleep. CONCLUSION: The EQ-5D-5L is acceptable for use in care but does not capture all aspects of health relevant to clients, and acceptability varies by subgroup.

Analysis of the alveolar shape in 3-D.

Mechanical forces affect the alveolar shape, depending on location and tissue composition, and vary during the respiratory cycle. This study performs alveolar morphomics in different lobes of human lungs using models generated from three-dimensional (3-D) micro-computed tomography (microCT) images. Cylindrical tissue samples (1.6 cm × 2 cm) were extracted from two nontransplantable donor lungs (one ex-smoker and one smoker, 3 samples per subject) that were air-inflated and frozen solid in liquid nitrogen vapor. Samples were scanned with microCT (11 µm/voxel). Within representative cubic regions of interest (5.5 mm edge length), alveoli were segmented to produce corresponding 3-D models from which quantitative data were obtained. The surface of segmented alveoli (n_alv_total = 23,587) was divided into individual planar surfaces (facets) and angles between facet normals were calculated. Moreover, the number of neighboring alveoli was estimated for every alveolus. In this study, we examined intraindividual differences in alveolar morphology, which were reproducible in the lungs of two subjects. The main aspects are higher mean alveolar volumes (v_alv: 6.64 × 106 and 6.63 × 106 µm3 vs. 5.78 × 106 and 6.29 × 106 µm3) and surface sizes (s_alv: 0.19 and 0.18 mm2 vs. 0.17 mm2 in both lower lobes) in both upper lung lobes compared with the lower lobes. An increasing number of facets (f_alv) from top to bottom (12 and 14 in the upper lobes; 14 and 15 in the lower lobes), as well as a decreasing number of alveolar neighbors (nei_alv: 9 and 8 in the upper lobes; 8 and 7 in the lower lobes) from the upper lobes to the lower lobes were observed. We could observe an increasing ratio of alveolar entrance size to the surface size of the alveoli from top to bottom (S_ratio_alv: 0.71 and 0.64 in the upper lobes, 0.73 and 0.70 in the lower lobes). The angles between facet normals (ang_alv) were larger in the upper lobes (67.72° and 62.44°) of both lungs than in the lower lobes (66.19° and 61.30°). By using this new approach of analyzing alveolar 3-D data, which enables the estimation of facet, neighbor, and shape characteristics, we aimed to establish the baseline measures for in-depth studies of mechanical conditions and morphology.

Some children with idiopathic toe walking display sensory processing difficulties but not all: A systematic review.

AIM: Idiopathic toe walking (ITW) is a diagnosis for children who toe walk without another diagnosis known to cause toe walking. Recent research has suggested that children with ITW may have mild motor planning challenges and sensory processing differences. The primary aim of this systematic review was to determine whether children diagnosed with ITW have differences in their sensory processing compared to typically developing children. Secondary aims included determining how sensory processing was assessed in this population and documenting the broad clinometric and psychometric properties of any assessment tools. METHODS: MEDLINE, CINAHL, AMED and Embase were searched for relevant literature in English. Studies were eligible for inclusion if they described children aged 3 and 18 with idiopathic toe walking and reported a sensory processing domain. RESULTS: Twelve articles met the inclusion criteria; however, only two papers included data permitting meta-analysis. Meta-analyses of vibration perception threshold using a random effect model were not significant (p = 0.31). Other data were synthesised by narrative and showed a high heterogeneity across multiple sensory processing domains. CONCLUSION: This study highlights that despite children with ITW often conceptualised as possessing sensory processing challenges, there is little evidence supporting this theory. Further research on sensory processing in children with this gait pattern is necessary.

A landscape assessment of the use of patient reported outcome measures in research, quality improvement and clinical care across a healthcare organisation.

BACKGROUND: Patient reported outcome measures (PROMs) can be used by healthcare organisations to inform improvements in service delivery. However, routine collection of PROMs is difficult to achieve across an entire healthcare organisation. An understanding of the use of PROMs within an organisation can provide valuable insights on the purpose, scope and practical considerations of PROMs collection, which can inform implementation of PROMs. METHODS: We used multiple research methods to assess the use of PROMs in research projects, data registries and clinical care across a healthcare organisation from January 2014 to April 2021. The methods included an audit of ethics applications approved by the organisation's human research ethics committee and registries which the health organisation had contributed data to; a literature review of peer-reviewed journal articles reporting on research projects conducted at the organisation; and a survey of health professionals use of PROMs in research projects, data registries and clinical care. The scope of PROMs was determined by classifying PROMs as either 'specific' to a particular disease and/or condition, or as a 'generic' measure with further classification based on the health domains they measured, using the World Health Organization International Classification Framework. Practical considerations included mode and timing of PROMs administration. Data were described using frequency and proportion. RESULTS: PROMs were used by 22% of research projects (n = 144/666), 68% of data registries (n = 13/19), and 76% of clinical specialties in their clinical care (n = 16/21). Disease specific PROMs were most commonly used: 83% of research projects (n = 130/144), 69% of clinical registries (n = 9/13), and 75% of clinical specialties (n = 12/16). Greater than 80% of research projects, clinical registries and clinical specialties measured health domains relating to both body impairments and participation in daily life activities. The most commonly used generic PROM was the EQ-5D (research projects n = 56/144, 39%; data registries n = 5/13, 38%; clinical specialties n = 4/16, 25%). PROMs used in clinical care were mostly paper-based (n = 47/55, 85%). CONCLUSIONS: We have elicited information on the use of PROMs to inform a health organisation wide implementation strategy. Future work will determine clinician and patient acceptability of the EQ-5D, and co-design a system for the collection of PROMs.

Brain tissue microstructural and free-water composition 13 years after very preterm birth.

There have been many studies demonstrating children born very preterm exhibit brain white matter microstructural alterations, which have been related to neurodevelopmental difficulties. These prior studies have often been based on diffusion MRI modelling and analysis techniques, which commonly focussed on white matter microstructural properties in children born very preterm. However, there have been relatively fewer studies investigating the free-water content of the white matter, and also the microstructure and free-water content of the cortical grey matter, in children born very preterm. These biophysical properties of the brain change rapidly during fetal and neonatal brain development, and therefore such properties are likely also adversely affected by very preterm birth. In this study, we investigated the relationship of very preterm birth (<30 weeks' gestation) to both white matter and cortical grey matter microstructure and free-water content in childhood using advanced diffusion MRI analyses. A total of 130 very preterm participants and 45 full-term control participants underwent diffusion MRI at age 13 years. Diffusion tissue signal fractions derived by Single-Shell 3-Tissue Constrained Spherical Deconvolution were used to investigate brain tissue microstructural and free-water composition. The tissue microstructural and free-water composition metrics were analysed using a voxel-based analysis and cortical region-of-interest analysis approach. Very preterm 13-year-olds exhibited reduced white matter microstructural density and increased free-water content across widespread regions of the white matter compared with controls. Additionally, very preterm 13-year-olds exhibited reduced microstructural density and increased free-water content in specific temporal, frontal, occipital and cingulate cortical regions. These brain tissue composition alterations were strongly associated with cerebral white matter abnormalities identified in the neonatal period, and concurrent adverse cognitive and motor outcomes in very preterm children. The findings demonstrate brain microstructural and free-water alterations up to thirteen years from neonatal brain abnormalities in very preterm children that relate to adverse neurodevelopmental outcomes.

Topographic Evolution of Anterior Cerebral Artery Infarction and Its Impact on Motor Impairment.

INTRODUCTION: Motor deficit is common following anterior cerebral artery (ACA) stroke. This study aimed to determine the impact on the motor outcome, given the location of descending corticofugal fiber tracts (from the primary motor cortex [M1], dorsal and ventral premotor area [PMdv], and supplementary motor area [SMA]) and the regional variations in collateral support of the ACA territory. METHODS: Patients with ACA vessel occlusion were included. Disruption to corticofugal fibers was inferred by overlap of tracts with a lesion on computed tomography perfusion at the onset and on magnetic resonance imaging (MRI) poststroke. The motor outcome was defined by dichotomized and combined National Institute of Health Stroke Scale (NIHSS) sub-scores for the arm and leg. Multivariate hierarchical partitioning was used to analyze the proportional contribution of the corticofugal fibers to the motor outcome. RESULTS: Forty-seven patients with a median age of 77.5 (interquartile range 68.0-84.5) years were studied. At the stroke onset, 96% of patients showed evidence of motor deficit on the NIHSS, and the proportional contribution of the corticofugal fibers to motor deficit was M1-33%, SMA-33%, and PMdv-33%. By day 7, motor deficit was present in <50% of patients and contribution of M1 fiber tracts to the motor deficit was reduced (M1-10.2%, SMA-61.0%, PMdv-28.8%). We confirmed our findings using publicly available high-resolution templates created from Human Connectome Project data. This also showed a reduction in involvement of M1 fiber tracts on initial perfusion imaging (33%) compared to MRI at a median time of 7 days poststroke (11%). CONCLUSION: Improvements in the motor outcome seen in ACA stroke may be due to the relative sparing of M1 fiber tracts from infarction. This may occur as a consequence of the posterior location of M1 fiber tracts and the evolving topography of ACA stroke due to the compensatory capacity of leptomeningeal anastomoses.

Modelling STEMI service delivery: a proof of concept study.

BACKGROUND: Access to individual percutaneous coronary intervention (PCI) centres has traditionally been determined by historical referral patterns along arbitrarily defined geographic boundaries. We set out to produce predictive models of ST-elevation myocardial infarction (STEMI) demand and time-efficient access to PCI centres. METHODS: Travel times from random addresses to PCI centres in Melbourne, Australia, were estimated using Google map application programming interface (API). Departures at 08:15 and 17:15 were compared with 23:00 to determine the effect of peak hour traffic congestion. Real-world ambulance travel times were compared with estimated travel times using Google map developer software. STEMI incidence per postcode was estimated by merging STEMI incidence per age group data with age group per postcode census data. PCI centre network configuration changes were assessed for their effect on hospital STEMI loading, catchment size, travel times and the number of STEMI cases within 30 min of a PCI centre. RESULTS: Nearly 10% of STEMI cases travelled more than 30 min to a PCI centre, increasing to 20% by modelling the removal of large outer metropolitan PCI centres (p<0.05). A model of 7 PCI centres compared favourably to the current existing network of 11 PCI centres (p=0.18 (afternoon), p=0.5 (morning and night)). The intraclass correlation between estimated travel times and ambulance travel times was 0.82, p<0.001. CONCLUSION: This paper provides a framework to integrate prehospital environmental variables, existing or altered healthcare resources and health statistics to objectively model STEMI demand and consequent access to PCI. Our methodology can be modified to incorporate other inputs to compute optimum healthcare efficiencies.

Anterior Cerebral Artery Stroke: Role of Collateral Systems on Infarct Topography.

Background and Purpose: The circle of Willis (CoW) and leptomeningeal anastomoses play an important role in transforming infarct topography following middle cerebral artery occlusion. Their role in infarct topography following anterior cerebral artery occlusion is not well understood. The aim of this study was to evaluate the role of the CoW and leptomeningeal anastomoses in modifying regional variation in infarct topography following occlusion of the anterior cerebral artery and its branches. Methods: Perfusion and magnetic resonance imaging of patients with anterior cerebral artery stroke and evidence of vessel occlusion were segmented and manually registered to standard brain template for voxel-wise comparison. Next, a computer model of the cerebral arteries was formulated as network of nodes connected by cylindrical pipes. The experiments included occlusion of successive branches of the anterior cerebral artery while the configurations of the CoW were varied. Results: Forty-seven patients with a median age of 77.5 years (interquartile range, 68.0­84.5 years) were studied. The regions with the highest probabilities of infarction were the superior frontal gyrus (probability =0.26) and anterior cingulate gyrus (probability =0.24). The regions around the posterior cingulate gyrus (probability =0.08), paracentral lobule (probability =0.05), precuneus and superior parietal lobule (probability =0.03) had a low probability of infarction. Following occlusions distal to the anterior communicating artery, the computer model demonstrated an increase in flow (>30%) in neighboring cortical arteries with leptomeningeal anastomoses. Conclusions: Traditionally the CoW has been regarded as the primary collateral system. However, our computer model shows that the CoW is only helpful in redirecting flow following proximal vessel occlusions (pre-anterior communicating artery). More important are leptomeningeal anastomoses, which play an essential role in distal vessel occlusions, influencing motor outcome by modifying the posterolateral extent of infarct topography.

Individual variation underlying brain age estimates in typical development.

Typical brain development follows a protracted trajectory throughout childhood and adolescence. Deviations from typical growth trajectories have been implicated in neurodevelopmental and psychiatric disorders. Recently, the use of machine learning algorithms to model age as a function of structural or functional brain properties has been used to examine advanced or delayed brain maturation in healthy and clinical populations. Termed 'brain age', this approach often relies on complex, nonlinear models that can be difficult to interpret. In this study, we use model explanation methods to examine the cortical features that contribute to brain age modelling on an individual basis. In a large cohort of n = 768 typically-developing children (aged 3-21 years), we build models of brain development using three different machine learning approaches. We employ SHAP, a model-agnostic technique to identify sample-specific feature importance, to identify regional cortical metrics that explain errors in brain age prediction. We find that, on average, brain age prediction and the cortical features that explain model predictions are consistent across model types and reflect previously reported patterns of regions brain development. However, while several regions are found to contribute to brain age prediction error, we find little spatial correspondence between individual estimates of feature importance, even when matched for age, sex and brain age prediction error. We also find no association between brain age error and cognitive performance in this typically-developing sample. Overall, this study shows that, while brain age estimates based on cortical development are relatively robust and consistent across model types and preprocessing strategies, significant between-subject variation exists in the features that explain erroneous brain age predictions on an individual level.

Towards understanding neurocognitive mechanisms of parenting: Maternal behaviors and structural brain network organization in late childhood.

A substantial body of knowledge suggests that exposure to adverse family environments - including violence and neglect - influences many aspects of brain development. Relatively less attention has been directed toward the influence of "normative" differences in parenting behaviors. Given the rapid brain reorganization during late childhood, parenting behaviors are particularly likely to impact the structure of the brain during this time. This study investigated associations between maternal parenting behaviors and the organization of structural brain networks in late childhood, as measured by structural covariance. One hundred and forty-five typically developing 8-year-olds and their mothers completed questionnaire measures and two observed interaction tasks; magnetic resonance imaging (MRI) scans were obtained from the children. Measures of maternal negative, positive, and communicative behavior were derived from the interaction tasks. Structural covariance networks based on partial correlations between cortical thickness estimates were constructed and estimates of modularity were obtained using graph theoretical analysis. High levels of negative maternal behavior were associated with low modularity. Minimal support was found for an association between positive maternal behaviors and modularity and between maternal communicative behaviors and modularity. Our findings suggest that variation in negative maternal behavior is associated with the structural organization of brain networks in children.

Investigating the brain structural connectome following working memory training in children born extremely preterm or extremely low birth weight.

Children born extremely preterm (EP, <28 weeks' gestation) or extremely low birth weight (ELBW, <1,000 g) are a vulnerable population at high risk of working memory impairments. We aimed to examine changes in the brain structural connectivity networks thought to underlie working memory performance, after completion of a working memory training program (Cogmed) compared with a placebo program in EP/ELBW children. This was a double-blind, placebo-controlled randomized trial (the Improving Memory in a Preterm Randomised Intervention Trial). Children born EP/ELBW received either the Cogmed or placebo program at 7 years of age (n = 91). A subset of children had magnetic resonance imaging of the brain immediately pre- and 2 weeks post-training (Cogmed n = 28; placebo n = 27). T1 -weighted and diffusion-weighted images were used to perform graph theoretical analysis of structural connectivity networks. Changes from pre-training to post-training in structural connectivity metrics were generally similar between randomized groups. There was little evidence that changes in structural connectivity metrics were related to changes in working memory performance from pre- to post-training. Overall, our results provide little evidence that the Cogmed working memory training program has training-specific effects on structural connectivity networks in EP/ELBW children.

The Associations Between Grey Matter Volume Covariance Patterns and Gait Variability-The Tasmanian Study of Cognition and Gait.

Greater gait variability predicts dementia. However, little is known about the neural correlates of gait variability. The aims of this study were to determine (1) grey matter volume covariance patterns associated with gait variability and (2) whether these patterns were associated with specific cognitive domains. Participants (n = 351; mean age 71.9 ± 7.1) were randomly selected from the Southern Tasmanian electoral roll. Step time, step length, step width and double support time were measured using an electronic walkway. Gait variability was calculated as the standard deviation of all steps for each gait measure. Voxel-based morphometry and multivariate covariance-based analyses were used to identify grey matter patterns associated with each gait variability measure. The individual expressions of grey matter patterns were correlated with processing speed, memory, executive and visuospatial functions. The grey matter covariance pattern of double support time variability included frontal, medial temporal, anterior cingulate, insula, cerebellar and striatal regions. Greater expression of this pattern was correlated with poorer performance in all cognitive functions (p < 0.001). The covariance pattern of step length variability included frontal, temporal, insula, occipital and cerebellar regions and was correlated with all cognitive functions (p < 0.05), except memory (p = 0.76). The covariance pattern of step width variability was limited to the cerebellum and correlated only with memory (p = 0.047). No significant pattern was identified for step time variability. In conclusion, different grey matter covariance patterns were associated with individual gait variability measures. These patterns were also correlated with specific cognitive functions, suggesting common neural networks may underlie both gait and cognition.

Sentiments expressed in YouTube public awareness campaigns: stroke.

Social media (YouTube) has been used to educate the public on stroke signs and the need to contact emergency hotline. We perform sentiment analysis to explore the emotional response to the 2006 North American and contrast this with the five Australian campaigns (2009-2015). The positive sentiment in the North American campaign provides insights for developing material for public health campaigns.

Long-term development of white matter fibre density and morphology up to 13 years after preterm birth: A fixel-based analysis.

BACKGROUND: It is well documented that infants born very preterm (VP) are at risk of brain injury and altered brain development in the neonatal period, however there is a lack of long-term, longitudinal studies on the effects of VP birth on white matter development over childhood. Most previous studies were based on voxel-averaged, non-fibre-specific diffusion magnetic resonance imaging (MRI) measures, such as fractional anisotropy. In contrast, the novel diffusion MRI analysis framework, fixel-based analysis (FBA), enables whole-brain analysis of microstructural and macrostructural properties of individual fibre populations at a sub-voxel level. We applied FBA to investigate the long-term implications of VP birth and associated perinatal risk factors on fibre development in childhood and adolescence. METHODS: Diffusion images were acquired for a cohort of VP (born <30 weeks' gestation) and full-term (FT, ≥37 weeks' gestation) children at two timepoints: mean (SD) 7.6 (0.2) years (n â€‹= â€‹138 VP and 32 FT children) and 13.3 (0.4) years (n â€‹= â€‹130 VP and 45 FT children). 103 VP and 21 FT children had images at both ages for longitudinal analysis. At every fixel (individual fibre population within an image voxel) across the white matter, we compared FBA metrics (fibre density (FD), cross-section (FC) and a combination of these properties (FDC)) between VP and FT groups cross-sectionally at each timepoint, and longitudinally between timepoints. We also examined associations between known perinatal risk factors and FBA metrics in the VP group. RESULTS: Compared with FT children, VP children had lower FD, FC and FDC throughout the white matter, particularly in the corpus callosum, tapetum, inferior fronto-occipital fasciculus, fornix and cingulum at ages 7 and 13 years, as well as the corticospinal tract and anterior limb of the internal capsule at age 13 years. VP children also had slower FDC development in the corpus callosum and corticospinal tract between ages 7 and 13 years compared with FT children. Within VP children, earlier gestational age at birth, lower birth weight z-score, and neonatal brain abnormalities were associated with lower FD, FC and FDC throughout the white matter at both ages. CONCLUSIONS: VP birth and concomitant perinatal risk factors are associated with fibre tract-specific alterations to axonal development in childhood and adolescence.

Accuracy of automated amygdala MRI segmentation approaches in Huntington's disease in the IMAGE-HD cohort.

Smaller manually-segmented amygdala volumes have been associated with poorer motor and cognitive function in Huntington's disease (HD). Manual segmentation is the gold standard in terms of accuracy; however, automated methods may be necessary in large samples. Automated segmentation accuracy has not been determined for the amygdala in HD. We aimed to determine which of three automated approaches would most accurately segment amygdalae in HD: FreeSurfer, FIRST, and ANTS nonlinear registration followed by FIRST segmentation. T1-weighted images for the IMAGE-HD cohort including 35 presymptomatic HD (pre-HD), 36 symptomatic HD (symp-HD), and 34 healthy controls were segmented using FreeSurfer and FIRST. For the third approach, images were nonlinearly registered to an MNI template using ANTS, then segmented using FIRST. All automated methods overestimated amygdala volumes compared with manual segmentation. Dice overlap scores, indicating segmentation accuracy, were not significantly different between automated approaches. Manually segmented volumes were most statistically differentiable between groups, followed by those segmented by FreeSurfer, then ANTS/FIRST. FIRST-segmented volumes did not differ between groups. All automated methods produced a bias where volume overestimation was more severe for smaller amygdalae. This bias was subtle for FreeSurfer, but marked for FIRST, and moderate for ANTS/FIRST. Further, FreeSurfer introduced a hemispheric bias not evident with manual segmentation, producing larger right amygdalae by 8%. To assist choice of segmentation approach, we provide sample size estimation graphs based on sample size and other factors. If automated segmentation is employed in samples of the current size, FreeSurfer may effectively distinguish amygdala volume between controls and HD.

Adherence to the Australian Dietary Guidelines Is Not Associated with Brain Structure or Cognitive Function in Older Adults.

BACKGROUND: Cognitive dysfunction is common in older adults, particularly in those with type 2 diabetes (T2D). Higher adherence to the Dietary Guidelines for Americans is associated with better brain health. However, it is unclear if adherence to the Australian Dietary Guidelines (ADG) is associated with cognition or brain structure in older adults. OBJECTIVE: The aims of this study were to 1) examine the relation between adherence to the ADG, cognition, and brain MRI and 2) determine whether T2D modifies any associations. METHODS: The Cognition and Diabetes in Older Tasmanians Study is a cross-sectional study in 688 people (n = 343 with T2D) aged 55-90 y. A validated 80-item food-frequency questionnaire was used to assess dietary intake. Adherence to the 2013 ADG was estimated using the Dietary Guidelines Index (DGI). Cognitive function in multiple domains was assessed with a comprehensive battery of neuropsychological tests and brain structure with MRI. Multivariable linear models were used to assess the associations between DGI, cognitive z scores, and brain structure. Effect modification for T2D was examined with a DGI × T2D product term. RESULTS: The mean age of the sample was 69.9 y (SD: 7.4 y), with 57.1% men. The mean DGI was 54.8 (SD: 10.7; range: 24.1-84.6). No associations were observed between the Australian DGI and cognition or brain MRI measures. T2D did not modify any associations (P > 0.05). CONCLUSIONS: This is the first study to investigate associations between adherence to the ADG and brain health in the older adults with and without T2D. Future prospective studies are required to clarify if there are long-term associations.

An ultrasound and formant study of manner contrasts at four coronal places of articulation.

This study examines consonant manner of articulation at four coronal places of articulation, using ultrasound and formant analyses of the Australian language Arrernte. Stop, nasal, and lateral articulations are examined at the dental, alveolar, retroflex, and alveo-palatal places of articulation: /t̪ n̪ l̪ / vs /t n l/ vs /ʈɳɭ/ vs /c ɲ ʎ/. Ultrasound data clearly show a more retracted tongue root for the lateral, and a more advanced tongue root for the nasal, as compared to the stop. However, the magnitude of the differences is much greater for the stop∼lateral contrast than for the stop∼nasal contrast. Acoustic results show clear effects on F1 in the adjacent vowels, in particular the preceding vowel, with F1 lower adjacent to nasals and higher adjacent to laterals, as compared to stops. Correlations between the articulatory and acoustic data are particularly strong for this formant. However, the retroflex place of articulation shows effects according to manner for higher formants as well, suggesting that a better understanding of retroflex acoustics for different manners of articulation is required. The study also suggests that articulatory symmetry and gestural economy are affected by the size of the phonemic inventory.