The effects of stress across the lifespan on the brain, cognition and mental health: A UK biobank study

Repeated overstimulation of the stress response system, caused by exposure to prolonged highly stressful experiences, is thought to affect brain structure, cognitive ability, and mental health. We tested the effects of highly stressful experiences during childhood and adulthood using data from the UK Biobank, a large-scale national health and biomedical study with over 500,000 participants. To do this, we defined four groups with high or low levels of childhood and/or adulthood stress. We then used T1-and diffusion-weighted MRI data to assess the macrostructure of grey matter and microstructure of white matter within limbic brain regions, commonly associated with the stress response. We also compared executive function and working memory between these groups. Our findings suggest that in females, higher levels of Childhood stress were associated with reduced connectivity within the posterior thalamic radiation and cingulum of the hippocampus. In males however, higher levels of Adulthood stress is associated with similar changes in brain microstructure in the posterior thalamic radiation and cingulum of the hippocampus. High stress in Childhood and Adulthood was associated with decreases in executive function and working memory in both males and females. Stress across the lifespan was also positively associated with the number of diagnosed mental health problems, with a stronger effect in females than in males. Finally, our findings also suggest that cognitive and mental health outcomes due to stress may be mediated by the sex specific stress related changes in brain microstructure. Together our findings demonstrate clear links between stress at distinct phases of the lifespan, changes in measures of brain microstructure, impairments in cognitive abilities and negative mental health outcomes.

Associations between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure in mid-childhood: An MRI study

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Neonatal hypoglycaemia is associated with damage to the brain in the acute phase.

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In mid-childhood, neonatal hypoglycaemia is associated with smaller brain regions.

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Deep grey matter regions such as the caudate and thalamus are implicated.

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Children with neonatal hypoglycemia had smaller occipital lobe cortical thickness.

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Grey matter may be especially vulnerable to long-term effects of neonatal hypoglycemia.

Neonatal hypoglycaemia is a common metabolic disorder that may cause brain damage, most visible in parieto-occipital regions on MRI in the acute phase. However, the long term effects of neonatal hypoglycaemia on the brain are not well understood. We investigated the association between neonatal hypoglycaemia and brain volumes, cortical thickness and white matter microstructure at 9–10 years.

Children born at risk of neonatal hypoglycaemia at ≥ 36 weeks’ gestation who took part in a prospective cohort study underwent brain MRI at 9–10 years. Neonatal hypoglycaemia was defined as at least one hypoglycaemic episode (at least one consecutive blood glucose concentration < 2.6 mmol/L) or interstitial episode (at least 10 min of interstitial glucose concentrations < 2.6 mmol/L). Brain volumes and cortical thickness were computed using Freesurfer. White matter microstructure was assessed using tract-based spatial statistics.

Children who had (n = 75) and had not (n = 26) experienced neonatal hypoglycaemia had similar combined parietal and occipital lobe volumes and no differences in white matter microstructure at nine years of age. However, those who had experienced neonatal hypoglycaemia had smaller caudate volumes (mean difference: −557 mm³, 95% confidence interval (CI), −933 to −182, p = 0.004) and smaller thalamus (−0.03%, 95%CI, −0.06 to 0.00; p = 0.05) and subcortical grey matter (−0.10%, 95%CI −0.20 to 0.00, p = 0.05) volumes as percentage of total brain volume, and thinner occipital lobe cortex (−0.05 mm, 95%CI −0.10 to 0.00, p = 0.05) than those who had not. The finding of smaller caudate volumes after neonatal hypoglycaemia was consistent across analyses of pre-specified severity groups, clinically detected hypoglycaemic episodes, and severity and frequency of hypoglycaemic events.

Neonatal hypoglycaemia is associated with smaller deep grey matter brain regions and thinner occipital lobe cortex but not altered white matter microstructure in mid-childhood.

The neurobiological characterization of distinct cognitive subtypes in early-phase schizophrenia-spectrum disorders

INTRODUCTION

Cognitive deficits are present in some, but not all patients with schizophrenia-spectrum disorders (SSD). We and others have demonstrated three cognitive clusters: cognitively intact patients, patients with deficits in a few domains and those with global cognitive deficits. This study aimed to identify cognitive subtypes of early-phase SSD with matched controls as a reference group, and evaluated cognitive subgroups regarding clinical and brain volumetric measures.

METHODS

Eighty-six early-phase SSD patients were included. Hierarchical cluster analysis was conducted using global performance on the Brief Assessment of Cognition in Schizophrenia (BACS). Cognitive subgroups were subsequently related to clinical and brain volumetric measures (cortical, subcortical and cortical thickness) using ANCOVA.

RESULTS

Three distinct cognitive clusters emerged: relative to controls we found one cluster of patients with preserved cognition (n = 25), one moderately impaired cluster (n = 38) and one severely impaired cluster (n = 23). Cognitive subgroups were characterized by differences in volume of the left postcentral gyrus, left middle caudal frontal gyrus and left insula, while differences in cortical thickness were predominantly found in fronto-parietal regions. No differences were demonstrated in subcortical brain volume.

DISCUSSION

Current results replicate the existence of three distinct cognitive subgroups including one relatively large group with preserved cognitive function. Cognitive subgroups were characterized by differences in cortical regional brain volume and cortical thickness, suggesting associations with cortical, but not subcortical development and cognitive functioning such as attention, executive functions and speed of processing.

Loss of association between plasma irisin levels and cognition in Alzheimer's disease

BACKGROUND

Irisin, an exercise-induced myokine, has been shown to have beneficial effects on cognitive and metabolic functions. However, previous studies assessing the levels of circulating irisin in patients with Alzheimer's disease (AD) or diabetes mellitus (DM) have provided inconsistent results. This suggests that the normal physiological action of irisin may be altered by disease-associated pathological conditions in target organs.

OBJECTIVE

To investigate the association of plasma levels of irisin with cognition and brain structures according to the presence or absence of AD and DM.

METHODS

Plasma levels of irisin, multi-domain cognition, and volumes of relevant brain regions were assessed using enzyme-linked immunoassay, neuropsychological test, and magnetic resonance imaging, respectively. We classified 107 participants by cognitive (cognitively normal [CN, n = 23], mild cognitive impairment [MCI, n = 49], and AD [n = 35]) and metabolic (non-DM [n = 75] and DM [n = 32]) states.

RESULTS

Disease state-stratified multiple regression analyses showed that plasma levels of irisin were positively associated with cognition only in participants without AD (CN plus MCI). By contrast, in participants with AD, these associations lost significance, and furthermore, higher levels of irisin indicated smaller hippocampal, superior temporal, and inferior frontal volumes. The association between plasma irisin levels and cognition was not affected by the presence of DM. Consistently, moderation analysis revealed that the relationship between plasma irisin levels and cognition or brain structures was significantly modified by the presence of AD, not that of DM.

CONCLUSION

Our findings suggest that the beneficial actions of circulating irisin on cognition may be attenuated by AD-induced pathological conditions in the brain.

CLOCK genetic variations are associated with age-related changes in sleep duration and brain volume

BACKGROUND

Although a connection between sleep disruption and brain aging has been documented, biological mechanisms need to be further clarified. Intriguingly, aging is associated with circadian rhythm and/or sleep dysfunction in a key gene regulating circadian rhythm, CLOCK, have been linked to both aging-related sleep disturbances and neurodegenerative diseases. This study aims to investigate how CLOCK genetic variation associates with sleep duration changes and/or volumetric brain alteration.

METHODS

This population-based cross-sectional study used data from the Korean Genome Epidemiology Study (KoGES), and analyzed sleep characteristics and genetic and brain imaging data in 2,221 subjects (mean 58.8±6.8 years, 50.2% male). Eleven single-nucleotide polymorphisms (SNPs) in CLOCK were analyzed using PLINK software v1.09 to test for their association with sleep duration and brain volume. Haplotype analysis was performed by using pair-wise linkage disequilibrium (LD) of CLOCK polymorphisms, and multivariate analysis of covariance was for statistical analysis.

RESULTS

Decreased sleep duration was associated with several SNPs in CLOCK intronic regions, with the highest significance for rs10002541 (P=1.58x10 -5). Five SNPs with the highest significance (rs10002541-rs6850524-rs4580704- rs3805151-rs3749474) revealed that CGTCT was the most prevalent. In the major CGTCT haplotype, decreased sleep duration over time was associated with lower cortical volumes predominantly in frontal and parietal regions. Less common haplotypes (GCCTC/CGTTC) had shorter sleep duration and more decreases in sleep duration over 8 years, which revealed smaller total and gray matter volumes, especially in frontal and temporal regions of the left hemisphere.

CONCLUSION

CLOCK genetic variations could be involved in age-related sleep and brain volume changes.

Evaluation of the correlation of the new Ballard scoring with the ultrasonographic optical nerve sheath diameter and brain volume of preterm infants

BACKGROUND

Optic nerve sheath diameter (ONSD) measurements with magnetic resonance imaging and ultrasonography in preterm infants are similar.

AIM

We measured ultrasonographic ONSD and calculated the brain volumes of preterm infants using two-dimensional cranial ultrasonography and explored the relationships thereof with gestational age, birth weight, head circumference, and new Ballard score.

METHOD

This prospective study included preterm infants admitted to the neonatal intensive care unit without intracranial pathology. Two images per eye were obtained from a linear array ultrasound transducer placed on the patient's superior eyelid. The ONSD was measured 3 mm behind the globe. The brain was considered an ellipsoid, and estimated absolute brain volumes were calculated by subtracting the volumes of the two lateral ventricles from the total brain volumes.

RESULTS

A total of 143 preterm infants (male 74, female 69) included in the study. The mean gestational age of the study population was 29.7 weeks (23-36), and the mean birth weight was 1390 g (500-2850). There was a significant difference in ONSD between the male and female gender. A significant, strong, and positive correlation was found between ONSD measurements and gestational age (r 0.901, p < 0.001), new Ballard score (r 0.946, p < 0.001), birth weight, head circumference, and brain volumes.

CONCLUSION

Our results suggested that ONSD measurements are highly correlated with anthropometry, and it could be a promising bedside, non-invasive objective tool for the determination of exact gestational age postnatally along with the new Ballard score.

Analysis of cerebellum with magnetic resonance 3D T1 sequence in individuals with chronic subjective tinnitus

Tinnitus is a symptom in which the patient can hear ringing, buzzing and similar sounds in the ear for 3 months longer. In our study, we aimed to analyse the cerebellum volume and cerebellum connections in patients with chronic tinnitus using VolBrain program. A total number of 10 patients and 10 otherwise healthy peoples records were then enrolled. Volumetric analysis was performed with automated segmentation of the cerebellum and its lobules, using magnetic resonance imaging (MRI). The mean volumes of 10 cerebellar volume were compared between the tinnitus and control groups. Quadrangular lobular portion of the cerebellum, the flocculonodular part and the volume of the central cerebellar lobule were decreased in the tinnitus group. White and grey matter decreased and the amygdala size was increased. We found statistically important volumetric changes in our study. VolBrain can be used in the future for analysing, diagnosis and treatment tinnitus patients. We recommend to use this practical, free of charge and easy programme to analyse for tinnitus patients. This may provide us with practical and useful information about the disease. In patients with tinnitus, the volume loss was 17.48% in the quadrangular lobe, 21% in the central lobule, and 9.33% in the total cerebellum volume.

Effects of a physical activity intervention on brain atrophy in older adults at risk of dementia: a randomized controlled trial

Lack of physical activity is a risk factor for dementia, however, the utility of interventional physical activity programs as a protective measure against brain atrophy and cognitive decline is uncertain. Here we present the effect of a randomized controlled trial of a 24-month physical activity intervention on global and regional brain atrophy as characterized by longitudinal voxel-based morphometry with T1-weighted MRI images. The study sample consisted of 98 participants at risk of dementia, with mild cognitive impairment or subjective memory complaints, and having at least one vascular risk factor for dementia, randomized into an exercise group and a control group. Between 0 and 24 months, there was no significant difference detected between groups in the rate of change in global, or regional brain volumes.

Grey-matter brain healthcare quotient and cognitive function: A large cohort study of an MRI brain screening system in Japan

There is sometimes a divergence between brain atrophy and impairments in cognitive function. The present study aimed to assess the relationship between cognitive function and the grey-matter brain healthcare quotient (GM-BHQ), which represents brain volume as a deviation value. In addition, we aimed to investigate lifestyle factors that can help maintain cognitive function despite brain atrophy. A total of 1,757 adults included in a Japanese MRI brain screening cohort underwent MRI. We classified the participants into two age groups: under 65 years old (young adult/middle age group) and over 64 years old (elder group). The GM-BHQ was more strongly correlated with cognitive function in the young adult/middle age group than in the elder group (p < .01). Regression analysis revealed that years of education was associated with the maintenance of cognitive function despite brain atrophy (p < .05). In conclusion, our findings suggest that the relationship between brain volume and cognitive function becomes more obscure with age.

A Meta-Analysis of Brain-Derived Neurotrophic Factor Effects on Brain Volume in Schizophrenia: Genotype and Serum Levels

AIM

The Val66Met single-nucleotide polymorphism (SNP) on the BDNF gene has established pleiotropic effects on schizophrenia incidence and morphologic alterations in the illness. The effects of brain-derived neurotrophic factor (BDNF) on brain volume measurements are however mixed seeming to be less established for most brain regions. The current meta-analytic review examined (1) the association of the Val66Met SNP and brain volume alterations in schizophrenia by comparing Met allele carriers to Val/Val homozygotes and (2) the association of serum BDNF with brain volume measurements.

METHOD

Studies included in the meta-analyses were identified through an electronic search of PubMed and PsycInfo (via EBSCO) for English language publications from January 2000 through December 2017. Included studies had conducted a genotyping procedure of Val66Met or obtained assays of serum BDNF and obtained brain volume data in patients with psychotic disorders. Nonhuman studies were excluded.

RESULTS

Study 1 which included 52 comparisons of Met carriers and Val/Val homozygotes found evidence of lower right and left hippocampal volumes among Met allele carriers with schizophrenia. Frontal measurements, while also lower among Met carriers, did not achieve statistical significance. Study 2 which included 7 examinations of the correlation between serum BDNF and brain volume found significant associations between serum BDNF levels and right and left hippocampal volume with lower BDNF corresponding to lower volumes.

DISCUSSION

The meta-analyses provided evidence of associations between brain volume alterations in schizophrenia and variations on the Val66Met SNP and serum BDNF. Given the limited number of studies, it remains unclear if BDNF effects are global or regionally specific.

White Matter but not Gray Matter Volumes Are Associated with Cognition in Community-Dwelling Chinese Populations

BACKGROUND

Few studies have investigated the association between cognition and brain volume associated with cerebral small vessel disease (CSVD).

OBJECTIVE

We investigated the association between cognition and brain volume and neuroimaging markers of CSVD in a community-dwelling population.

METHODS

Participants (n = 993, age≥35 years) from the community-based Shunyi Study were included to investigate the association between neuroimaging markers and cognition cross-sectionally. Magnetic resonance imaging markers included brain volume measurements of the total cerebrum, white matter, gray matter, and CSVD imaging markers. Cognitive performance was assessed using neuropsychological tests of the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Fuld Object Memory, digit span, Trail Making Test (TMT)-A, and TMT-B.

RESULTS

For brain volume measurement, subcortical white matter fraction was positively associated with MMSE score (β= 0.034, p = 0.0062) and MoCA score (β= 0.034, p = 0.0174), and negatively associated with TMT-A and TMT-B completion time (β= -2.319, p = 0.0002; β= -2.827, p = 0.0073, respectively). For evaluation of CSVD imaging markers, the presence of lacunes was positively associated with TMT-B completion time (β= 17.241, p = 0.0028).

CONCLUSION

In community-dwelling populations, reduced white matter volumes, as a consequence of aging and vascular damage, are associated with worse global cognition and executive function. Our findings provide potential insights into the correlation between cognition and CSVD-associated subcortical white matter injury.

Associations of dietary markers with brain volume and connectivity: A systematic review of MRI studies

The high prevalence of unhealthy dietary patterns and related brain disorders, such as dementia, emphasizes the importance of research that examines the effect of dietary factors on brain health. Identifying markers of brain health, such as volume and connectivity, that relate to diet is an important first step towards understanding the lifestyle determinants of healthy brain ageing. We conducted a systematic review of 52 studies (total n = 21,221 healthy participants aged 26-80 years, 55 % female) that assessed with a range of MRI measurements, which brain areas, connections, and cerebrovascular factors were associated with dietary markers. We report associations between regional brain measures and dietary health. Collectively, lower diet quality was related to reduced brain volume and connectivity, especially in white and grey matter of the frontal, temporal and parietal lobe, cingulate, entorhinal cortex and the hippocampus. Associations were also observed in connecting fibre pathways and in particular the default-mode, sensorimotor and attention networks. However, there were also some inconsistencies in research methods and findings. We recommend that future research use more comprehensive and consistent dietary measures, more representative samples, and examine the role of key subcortical regions previously highlighted in relevant animal work.

Associations between neighborhood greenspace and brain imaging measures in non-demented older adults: the Cardiovascular Health Study

PURPOSE

Greater neighborhood greenspace has been associated with brain health, including better cognition and lower odds of Alzheimer's disease in older adults. We investigated associations between neighborhood greenspace and brain-based magnetic resonance imaging (MRI) measures and potential effect modification by sex or apolipoprotein E genotype (APOE), a risk factor for Alzheimer's disease.

METHODS

We obtained a sample of non-demented participants 65 years or older (n = 1125) from the longitudinal, population-based Cardiovascular Health Study (CHS). Greenspace data were derived from the National Land Cover Dataset. Adjusted multivariable linear regression estimated associations between neighborhood greenspace five years prior to the MRI and left and right hippocampal volume and 10-point grades of ventricular size and burden of white matter hyperintensity. Interaction terms tested effect modification by APOE genotype and sex. CHS data (1989-1999) were obtained/analyzed in 2020.

RESULTS

Participants were on average 79 years old [standard deviation (SD) = 4], 58% were female, and 11% were non-white race. Mean neighborhood greenspace was 38% (SD = 28%). Greater proportion of greenspace in the neighborhood five years before MRI was borderline associated with lower ventricle grade (estimate: - 0.30; 95% confidence interval: - 0.61, 0.00). We observed no associations between greenspace and the other MRI outcome measures and no evidence of effect modification by APOE genotype and sex.

CONCLUSION

This study suggests a possible association between greater greenspace and less ventricular enlargement, a measure reflecting global brain atrophy. If confirmed in other longitudinal cohort studies, interventions and policies to improve community greenspaces may help to maintain brain health in older age.

Grip strength from midlife as an indicator of later-life brain health and cognition: evidence from a British birth cohort

BACKGROUND

Grip strength is an indicator of physical function with potential predictive value for health in ageing populations. We assessed whether trends in grip strength from midlife predicted later-life brain health and cognition.

METHODS

446 participants in an ongoing British birth cohort study, the National Survey of Health and Development (NSHD), had their maximum grip strength measured at ages 53, 60-64, and 69, and subsequently underwent neuroimaging as part of a neuroscience sub-study, referred to as "Insight 46", at age 69-71. A group-based trajectory model identified latent groups of individuals in the whole NSHD cohort with below- or above-average grip strength over time, plus a reference group. Group assignment, plus standardised grip strength levels and change from midlife were each related to measures of whole-brain volume (WBV) and white matter hyperintensity volume (WMHV), plus several cognitive tests. Models were adjusted for sex, body size, head size (where appropriate), sociodemographics, and behavioural and vascular risk factors.

RESULTS

Lower grip strength from midlife was associated with smaller WBV and lower matrix reasoning scores at age 69-71, with findings consistent between analysis of individual time points and analysis of trajectory groups. There was little evidence of an association between grip strength and other cognitive test scores. Although greater declines in grip strength showed a weak association with higher WMHV at age 69-71, trends in the opposite direction were seen at individual time points with higher grip strength at ages 60-64, and 69 associated with higher WMHV.

CONCLUSIONS

This study provides preliminary evidence that maximum grip strength may have value in predicting brain health. Future work should assess to what extent age-related declines in grip strength from midlife reflect concurrent changes in brain structure.

Increased habitual flavonoid intake predicts attenuation of cognitive ageing in twins

BACKGROUND

Although the pathophysiology of cognitive decline is multifactorial, and modifiable by lifestyle, the evidence for the role of diet on cognitive function is still accumulating, particularly the potentially preventive role of constituents of plant-based foods.

METHODS

We aimed to determine whether higher habitual intake of dietary flavonoids, key components of plant-based diets, were associated with improved cognition and medial temporal lobe volumes using three complementary approaches (longitudinal, cross-sectional and co-twin analyses). In 1126 female twins (n=224 with a 10-year follow-up of diet and cognition data) aged 18-89 years, habitual intakes of total flavonoids and seven subclasses (flavanones, anthocyanins, flavan-3-ols, flavonols, flavones, polymeric flavonoids (and proanthocyanidins separately)) were calculated using validated food frequency questionnaires. Cognition was assessed using the Cambridge Neuropsychological Test Automated Battery test. Hippocampal volumes were measured in a subset using magnetic resonance imaging (16 monozygotic-twin pairs). Statistical models were adjusted for a range of diet and lifestyle factors.

RESULTS

Higher intakes of flavanones (tertile (T)3-T1=0.45, 95%CI 0.13,0.77; p=0.01) and anthocyanins (T3-T1=0.45, 95%CI 0.08,0.81; p=0.02) were associated with improvements in age-related cognition score over 10 years. In cross-sectional analysis higher intake of flavanones (T3-T1= 0.12, 95% CI 0.02, 0.21; p=0.02) and proanthocyanidins (T3-T1= 0.13, 95% CI 0.02, 0.24; p=0.02) were associated with improved paired-associates learning. Higher intake of anthocyanins was significantly associated with improved executive function (T3-T1= -0.52, 95% CI 0.19, 0.84; p=0.001) and with faster simple reaction times (T3-T1= -18.1, 95% CI -35.4, -0.7; p=0.04). In co-twin analysis, those with higher anthocyanin (2.0%, p=0.01) and proanthocyanidin (2.0%, p=0.02) intakes at baseline had the largest left hippocampal volumes after 12 years.

CONCLUSION

Small increases in habitual intake of flavonoid-rich foods (containing anthocyanins, flavanones and proanthocyanidins; equivalent to approximately two servings of oranges and blueberries per day) over long time periods have the potential to attenuate cognitive ageing.

Brain atrophy rates in patients with multiple sclerosis on long term natalizumab resembles healthy controls

BACKGROUND

Clinically stable multiple sclerosis (MS) patients often have negligible inflammatory MRI changes. Brain atrophy may provide insight into subclinical disease progression. The objective was to compare brain atrophy rates in stable patients on long term natalizumab treatment vs. age and gender matched healthy non-MS controls (HC) prospectively over two-years examining brain volume, cognition, and patient reported outcomes (PROs).

METHODS

MS patients treated with natalizumab for a minimum of 2 years, age 18-60 were recruited and compared with age- and gender-matched healthy controls (HC). Both groups were followed prospectively to obtain two years of consecutive magnetic resonance imaging, clinical and PRO data. Baseline normalized brain volume (NBV), yearly T2 lesion volume (T2LV), and percent brain volume change (PBVC) were measured using SIENAX, JIM 6.0, and SIENA respectively. Neuropsychological tests from the MACFIMS battery were selected to optimize assessments for impairments in the domains of information processing speed and memory. Patient reported outcomes (PROs) for domains of physical, mental and social quality of life were evaluated using the NeuroQol short forms.

RESULTS

Forty-eight natalizumab and 62 HC completed all study visits. At baseline, unadjusted mean NBV (natalizumab=1508.80cm (Popescu et al., 2013) vs. HC=1539.23cm (Popescu et al., 2013); p=0.033) and median baseline T2LV (natalizumab=1724.62mm (Popescu et al., 2013) vs. HC=44.20mm (Popescu et al., 2013); p=<0.0001) were different. The mean PBVC at year 2, adjusted for gender and baseline age was -0.57% (CI: 0.7620, -0.3716) for natalizumab and -0.50% (-0.7208, -0.2831) for HC, but the difference between groups was not statistically significant (0.073%; p=0.62). Over the 2-year period, HC demonstrated mild improvements in some cognitive tests vs. natalizumab subjects. However, PROs were similar between the two groups.

CONCLUSION

Stable MS patients on natalizumab have similar brain volume loss as people who do not have MS, suggesting normalization of brain atrophy.

Relation of a Socioeconomic Index with Cognitive Function and Neuroimaging in Hypertensive Individuals

BACKGROUND

Socioeconomic factors are important contributors to brain health. However, data from developing countries (where social inequalities are the most prominent) are still scarce, particularly about hypertensive individuals.

OBJECTIVE

To evaluate the relationship between socioeconomic index, cognitive function, and cortical brain volume, as well as determine whether white matter hyperintensities are mediators of the association of the socioeconomic index with cognitive function in hypertensive individuals.

METHODS

We assessed 92 hypertensive participants (mean age = 58±8.6 years, 65.2%female). Cognitive evaluation and neuroimaging were performed and clinical and sociodemographic data were collected using questionnaires. A socioeconomic index was created using education, income, occupation (manual or non-manual work), and race. The associations of the socioeconomic index with cognitive performance and brain volume were investigated using linear regression models adjusted for age, sex, time of hypertension since diagnosis, and comorbidities. A causal mediation analysis was also conducted.

RESULTS

Better socioeconomic status was associated with better visuospatial ability, executive function, and global cognition. We found associations between a better socioeconomic index and a higher parietal lobe volume. White matter hyperintensities were also not mediators in the relationship between the socioeconomic index and cognitive performance.

CONCLUSION

Socioeconomic disadvantages are associated with worse cognitive performance and brain volume in individuals with hypertension.

Improved brain perfusion after electrical cardioversion of atrial fibrillation

AIMS

Atrial fibrillation (AF) has been associated with reduced brain volume, cognitive impairment, and reduced cerebral blood flow. The causes of reduced cerebral blood flow in AF are unknown, but no reduction was seen in individuals without the arrhythmia in a previous study. The aim of this study was to test the hypothesis that brain perfusion, measured with magnetic resonance imaging (MRI), improves after cardioversion of AF to sinus rhythm (SR).

METHODS AND RESULTS

All patients undergoing elective cardioversion at our institution were invited to participate. A total of 44 individuals were included. Magnetic resonance imaging studies were done before and after cardioversion with both brain perfusion and cerebral blood flow measurements. However, 17 did not complete the second MRI as they had a recurrence of AF during the observation period (recurrent AF group), leaving 17 in the SR group and 10 in the AF group to complete both measurements. Brain perfusion increased after cardioversion to SR by 4.9 mL/100 g/min in the whole brain (P < 0.001) and by 5.6 mL/100 g/min in grey matter (P < 0.001). Cerebral blood flow increased by 58.6 mL/min (P < 0.05). Both brain perfusion and cerebral blood flow remained unchanged when cardioversion was unsuccessful.

CONCLUSION

In this study of individuals undergoing elective cardioversion for AF, restoration, and maintenance of SR for at least 10 weeks after was associated with an improvement of brain perfusion and cerebral blood flow measured by both arterial spin labelling and phase contrast MRI. In those individuals where cardioversion was unsuccessful, there was no change in perfusion or blood flow.

Neurodevelopmental impairment is associated with altered white matter development in a cohort of school-aged children born very preterm

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Over 30% of children born VPT have neurodevelopmental impairment.

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VPT children with neurodevelopmental impairment have smaller total brain volume.

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VPT children with neurodevelopmental impairment have lower FA and higher RD.

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Neurodevelopmental impairment in a VPT cohort may reflect altered microstructure.

Individuals born very preterm (<32 weeks gestation) have altered brain growth and white matter maturation relative to their full-term peers, and approximately 30% will experience neurodevelopmental impairment. We investigated the relationship between neurodevelopmental impairment and MRI measures of white matter microstructure and brain volume.

Children born before 30 weeks’ gestation or who had very low birthweight (< 1500 g) underwent neurodevelopmental assessment and MRI at age 7 years as part of the PIANO study, a New Zealand-based cohort study. Fractional anisotropy (FA) and diffusivity measures were derived from diffusion tensor imaging to index white matter microstructure. Volumes were derived from T1-weighted imaging. Neurodevelopmental impairment was defined as a score < 85 on the Wechsler Intelligence Scale for Children, <5th centile on the Movement Assessment Battery for Children or a diagnosis of cerebral palsy by a paediatrician. Relationships between MRI and neurodevelopmental impairment were assessed with general linear models adjusted for sex, gestational age at birth, birthweight z-score, age at assessment, New Zealand Deprivation index score and multiplicity.

Children with neurodevelopmental impairment (n = 38) had smaller total brain, cortical grey matter and cerebral white matter volumes compared to children without neurodevelopmental impairment (n = 62) (p < 0.05, false discovery rate corrected), but the regional volume differences did not remain significant after adjustment for total brain volume. Lower FA and higher radial diffusivity were observed in the superior longitudinal fasciculi, uncinate fasciculi and right hemisphere corticospinal tract in children with neurodevelopmental impairment. This may reflect differences in cellular properties such as myelination or axonal packing. Neurodevelopmental impairment may reflect smaller overall brain volume and altered microstructure in white matter tracts that are important for language, cognitive and motor functioning.

Higher Framingham Risk Scores are associated with greater loss of brain volume over time in multiple sclerosis

BACKGROUND

Few studies have evaluated the association between comorbidities associated with increased vascular risk and brain volume changes in multiple sclerosis (MS). To date, findings have not been consistent with respect to which comorbidities are associated with lower brain volumes or whether comorbidities associated with increased vascular risk are associated with greater brain volume loss over time.

OBJECTIVES

We aimed to evaluate the association between the Framingham Risk Score (FRS) which evaluates vascular risk and normalized whole brain volume in MS.

METHODS

We included 98 participants with MS who underwent two brain MRIs two years apart, from which whole brain volumes were calculated. Each participant reported their comorbidities and medications taken. Blood pressure, height and weight were recorded and we calculated the FRS. We tested the association between the FRS at baseline and brain volume at the second time point using quantile regression adjusting for baseline normalized brain volume, age, gender and use of disease-modifying therapy.

RESULTS

As the FRS increased, brain volume was lower, both at enrollment (β= -0.24; 95%CI: -0.42, -0.04) and at follow-up (-0.27; 95%CI: -0.45, -0.08). After further adjustment for age, gender, and use of disease modifying therapy, higher FRS remained associated with lower brain volume at follow-up at the 90th percentile of brain volume (β= -2.22; 95%CI: -3.40, -1.04) but not at the 10th or 50th percentiles.

CONCLUSION

Higher FRS were associated with lower brain volumes in persons with MS at baseline, and with brain volume loss over time. This effect was most pronounced for persons with higher brain volumes at baseline, which suggests that prevention, detection and effective management of comorbidities associated with vascular risk in people with MS is particularly important early in the disease course.

Impact of maternal hypertensive disorders of pregnancy on brain volumes at term-equivalent age in preterm infants: A voxel-based morphometry study

OBJECTIVES

Infants born to mothers with hypertensive disorders of pregnancy (HDP) reportedly have negative behavioral and neurodevelopmental outcomes. However, the effects of maternal HDP on infant brain growth have not been fully evaluated. We aimed to evaluate brain volumes and brain injury in preterm infants born to mothers with HDP using magnetic resonance (MR) imaging at term-equivalent age.

STUDY DESIGN

In this cohort study, MR imaging was performed for 94 preterm infants born before 34 weeks of gestation at Nagoya University Hospital between 2010 and 2018. Twenty infants were born to mothers with HDP and 74 to mothers without HDP.

MAIN OUTCOME MEASURES

Total brain volumes and regional volumetric alterations were assessed by voxel-based morphometry, and brain injury was evaluated using the Kidokoro global brain abnormality score. Developmental quotient was assessed at a corrected age of 1.5 years in 59 infants (HDP, n = 11; non-HDP, n = 48).

RESULTS

No significant differences were observed in the gray and white matter volumes of the two groups (HDP: 175 ± 24 mL, 137 ± 13 mL, respectively; non-HDP: 172 ± 24 mL, 142 ± 13 mL, respectively). Additionally, no regional volumetric alterations were observed between the two groups after covariate adjustment (gestational age and infant sex). The total Kidokoro score and developmental quotient were similar in both groups.

CONCLUSIONS

No significant differences in the global and regional brain volumes were observed. Further research is needed to confirm our findings at different time points of MR imaging and in different populations.

Cross-Sectional Volumes and Trajectories of the Human Brain, Gray Matter, White Matter and Cerebrospinal Fluid in 9473 Typically Aging Adults

Accurate knowledge of adult human brain volume (BV) is critical for studies of aging- and disease-related brain alterations, and for monitoring the trajectories of neural and cognitive functions in conditions like Alzheimer's disease and traumatic brain injury. This scoping meta-analysis aggregates normative reference values for BV and three related volumetrics-gray matter volume (GMV), white matter volume (WMV) and cerebrospinal fluid volume (CSFV)-from typically-aging adults studied cross-sectionally using magnetic resonance imaging (MRI). Drawing from an aggregate sample of 9473 adults, this study provides (A) regression coefficients β describing the age-dependent trajectories of volumetric measures by sex within the range from 20 to 70 years based on both linear and quadratic models, and (B) average values for BV, GMV, WMV and CSFV at the representative ages of 20 (young age), 45 (middle age) and 70 (old age). The results provided synthesize ~20 years of brain volumetrics research and allow one to estimate BV at any age between 20 and 70. Importantly, however, such estimates should be used and interpreted with caution because they depend on MRI hardware specifications (e.g. scanner manufacturer, magnetic field strength), data acquisition parameters (e.g. spatial resolution, weighting), and brain segmentation algorithms. Guidelines are proposed to facilitate future meta- and mega-analyses of brain volumetrics.

Structural volume and cortical thickness differences between males and females in cognitively normal, cognitively impaired and Alzheimer's dementia population

We investigated differences due to sex in brain structural volume and cortical thickness in older cognitively normal (N=742), cognitively impaired (MCI; N=540) and Alzheimer's Dementia (AD; N=402) individuals from the ADNI and AIBL datasets (861 Males and 823 Females). General linear models were used to control the effect of relevant covariates including age, intracranial volume, magnetic resonance imaging (MRI) scanner field strength and scanner types. Significant volumetric differences due to sex were observed within different cortical and subcortical regions of the cognitively normal group. The number of significantly different regions was reduced in the MCI group, and no region remained different in the AD group. Cortical thickness was overall thinner in males than females in the cognitively normal group, and likewise, the differences due to sex were reduced in the MCI and AD groups. These findings were sustained after including cerebrospinal fluid (CSF) Tau and phosphorylated tau (pTau) as additional covariates.

Serum neurofilament light is a sensitive biomarker that reflects grey matter volume in Japanese patients with multiple sclerosis

OBJECTIVE

To evaluate the degree of neuroaxonal injury in Japanese multiple sclerosis (MS) patients using serum neurofilament light (sNfL) and to investigate the relationship of sNFL with the degree of brain volume.

METHODS

sNfL levels in 82 consecutive Japanese MS patients in remission were cross-sectionally evaluated using a single molecule array assay. Within this sample, cross-sectional volumetric brain MRI data was evaluated in 80 patients, and longitudinal data was evaluated in 63 patients.

RESULTS

MS patients (female/male = 61/21), including those with relapsing-remitting MS (82%), secondary progressive MS (17%), and primary progressive MS (1%), were studied. The mean age of the patients was 41.2 ± 8.7 years, and 77 of the MS patients (94%) were treated with disease-modifying therapy (DMT). Their median sNfL level was 7.985 (IQR, 5.959-10.9), and their sNfL levels were significantly correlated with their grey matter volume and their age. A standard least squares regression model revealed that approximately 57% of the variation in grey matter volume could be explained by a regression equation using three explanatory variables: sNfL concentration, age, and sex. Moreover, the sNfL level multiplied by disease duration was significantly correlated with the Expanded Disability Status Scale (EDSS) scores and whole and grey matter volumes.

CONCLUSION

Although neuroaxonal injury appeared to be mild in our Japanese MS patients, their sNfL levels significantly reflected grey matter volume. Moreover, when multiplied by the disease duration, sNfL can reflect disability and brain volume.