Search

A comprehensive characterization of the brain’s white matter is critical for improving our understanding of healthy and diseased aging. Here we used diffusion-weighted magnetic resonance imaging (dMRI) to estimate age and sex effects on white matter microstructure in a cross-sectional sample of 15,628 adults aged 45–80 years old (47.6% male, 52.4% female). Microstructure was assessed using the following four models: a conventional single-shell model, diffusion tensor imaging (DTI); a more advanced single-shell model, the tensor distribution function (TDF); an advanced multi-shell model, neurite orientation dispersion and density imaging (NODDI); and another advanced multi-shell model, mean apparent propagator MRI (MAPMRI). Age was modeled using a data-driven statistical approach, and normative centile curves were created to provide sex-stratified white matter reference charts. Participant age and sex substantially impacted many aspects of white matter microstructure across the brain, with the advanced dMRI models TDF and NODDI detecting such effects the most sensitively. These findings and the normative reference curves provide an important foundation for the study of healthy and diseased brain aging. Supplementary Information The online version contains supplementary material available at 10.1007/s11682-021-00548-y.

Background and importance Palpitation is one of the commonest presenting complaints to the emergency department (ED). Diagnosis depends on capturing an ECG during the episode. Unlike syncope, patients retain consciousness and therefore their ability to activate an ECG event recorder. The Investigation of Palpitation in the ED study demonstrated Food and Drug Administration approved AliveCor/Kardia device that links to a smartphone app was safe and effective. A Smartphone Palpitation and Pre-syncope Ambulatory Care Clinic was therefore established. Objectives To review the first year of patients attending the service to determine the number and cost-effectiveness of cardiac dysrhythmias diagnoses. Design Single-center cohort study. Settings and participants Royal Infirmary of Edinburgh, UK. All patients (over 16 years) presenting consecutively to ED with palpitation or pre-syncope, whose ECG was normal, had a compatible device and where an underlying cardiac dysrhythmia was possible were enrolled. Intervention Ambulatory Care Clinic utilizing the AliveCor/Kardia device. Outcome measures and analysis Number diagnosed with cardiac dysrhythmia and mean cost per diagnosis. Main results Between 24 July 2019 and 23 July 2020, 290 consecutive patients were referred of age 16-80 years (mean 43.3, SD 15.0). One hundred twenty (41.4%) were male. Two hundred thirty-seven (81.7%) were fitted with the device and 220 (75.9%) underwent full investigation. Seventeen of 237 (7.2%) patients had a cardiac diagnosis (12 atrial fibrillation/flutter, 5 supraventricular tachycardia and 1 atrial tachycardia). Conclusions There were 17 cardiac diagnoses (7.2%). The cost per symptomatic rhythm diagnosis was 358 GBP (~415 Euro) and the cost per cardiac dysrhythmia diagnosis was 4570 GBP (~5298 Euro). A smartphone-based event recorder clinic should be considered for ED palpitation patients.

Background and Objectives: The Investigation of Palpitations in the ED (IPED) study showed that a smartphone-based event recorder increased the number of patients in whom an electrocardiogram (ECG) was captured during symptoms over five-fold to more than 55% at 90 days compared to standard care and concluded that this safe, non-invasive and easy-to-use device should be considered part of on-going care to all patients presenting acutely with unexplained palpitations or pre-syncope. This study reports the process of establishing a smartphone palpitation and pre-syncope ambulatory care Clinic (SPACC) service. Materials and Methods: A clinical standard operating procedure (SOP) was devised, and funding was secured through a business case for the purchase of 40 AliveCor devices in the first instance. The clinic was launched on 22 July 2019. Results: Between 22 July 2019 and 31 October 2019, 68 patients seen in the emergency departments (EDs) with palpitations or pre-syncope were referred to SPACC. Of those, 30 were male and 38 were female, and the mean age was 45.8 years old (SD 15.1) with a range from 18 years old to 80 years old. A total of 50 (74%) patients underwent full investigation. On the first assessment, seven (10%) patients were deemed to have non-cardiac palpitations and were not fitted with the device. All patients who underwent full investigation achieved symptomatic rhythm correlation most with sinus rhythm, ventricular ectopics, or bigeminy. A symptomatic cardiac dysrhythmia was detected in six (8.8%) patients. Three patients had supraventricular tachycardia (4%), two had atrial fibrillation (3%), and one had atrial flutter (2%). Qualitative feedback from the SPACC team suggested several areas where improvement to the clinic could be made. Conclusion: We believe a smartphone palpitation service based on ambulatory care is simple to implement and is effective at detecting cardiac dysrhythmia in ED palpitation patients.

Accurate reward predictions include forecasting both what a reward will be and when a reward will occur. We tested how variations in the certainty of reward outcome and certainty in timing of feedback presentation modulate neural indices of reward prediction errors using the reward positivity (RewP) component of the scalp-recorded brain event-related potential (ERP). In a within-subjects design, seventy-three healthy individuals completed two versions of a cued doors task; one cued the probability of a reward outcome while the other cued the probability of a delay before feedback. Replicating previous results, RewP amplitude was larger for uncertain feedback compared to certain feedback. Additionally, RewP amplitude was differentially associated with uncertainty of presence/absence of reward, but not uncertainty of feedback timing. Findings suggest a dissociation in that RewP amplitude is modulated by reward prediction certainty but is less affected by certainty surrounding timing of feedback.

Food-related inhibitory control, the ability to withhold a dominant response towards highly palatable foods, influences dietary decisions. Food-related inhibitory control abilities may increase following a bout of aerobic exercise; however, the impact of exercise intensity on both food-related inhibitory control and broader cognitive control processes is currently unclear. We used a high-powered, within-subjects, crossover design to test how relative intensity of aerobic exercise influenced behavioral (response time, accuracy) and neural (N2 and P3 components of the scalp-recorded event-related potential [ERP]) measures of food-related inhibitory and cognitive control. Two hundred and thirteen participants completed three separate conditions separated by approximately one week in randomized order: two exercise conditions (35% [moderate] or 70% [vigorous] of VO2max) and seated rest. Directly following exercise or rest, participants completed a food-based go/no-go task and a flanker task while electroencephalogram data were recorded. Linear mixed models showed generally faster response times (RT) and improved accuracy following vigorous exercise compared to rest, but not moderate-intensity exercise; RTs and accuracy did not differ between moderate intensity exercise and rest conditions. N2 and P3 amplitudes were larger following vigorous exercise for the food-based go/no-go task compared to rest and moderate intensity exercise. There were no differences between exercise conditions for N2 amplitude during the flanker task; however, P3 amplitude was more positive following vigorous compared to rest, but not moderate exercise. Gender did not moderate exercise outcomes. Results suggest improved and more efficient food- related recruitment of later inhibitory control and cognitive control processes following vigorous exercise.

The brain’s white matter microstructure, as assessed using diffusion-weighted MRI (DWI), changes significantly with age and also exhibits significant sex differences. Here we examined the ability of a traditional diffusivity metric (fractional anisotropy derived from diffusion tensor imaging, DTI-FA) and advanced diffusivity metrics (fractional anisotropy derived from the tensor distribution function, TDF-FA; neurite orientation dispersion and density imaging measures of intracellular volume fraction, NODDI-ICVF; orientation dispersion index, NODDI-ODI; and isotropic volume fraction, NODDI-ISOVF) to detect sex differences in white matter aging. We also created normative aging reference curves based on sex. Diffusion tensor imaging (DTI) applies a single-tensor diffusion model to single-shell DWI data, while the tensor distribution function (TDF) fits a continuous distribution of tensors to single-shell DWI data. Neurite orientation dispersion and density imaging (NODDI) fits a multi-compartment model to multi-shell DWI data to distinguish intra- and extracellular contributions to diffusion. We analyzed these traditional and advanced diffusion measures in a large population sample available through the UK Biobank (15,394 participants; age-range: 45-80 years) by using linear regression and fractional polynomials. Advanced diffusivity metrics (NODDI-ODI, NODDI-ISOVF, TDF-FA) detected significant sex differences in aging, whereas a traditional metric (DTI-FA) did not. These findings suggest that future studies examining sex differences in white matter aging may benefit from including advanced diffusion measures.

Error-monitoring processes may be affected by transdiagnostic dimensions of psychopathology symptoms including trait anxiety, worry, and severity of depressive symptoms. We tested the relationship between continuous measures of anxiety and depressive symptomology and neural correlates of error-monitoring as measured by time-frequency domain delta and theta oscillatory power and time-domain error-related negativity (ERN) amplitude extracted from the electroencephalogram (EEG). Secondary analyses tested for diagnostic group differences in error-related neural responses in individuals with generalized anxiety disorder (GAD), major depressive disorder (MDD), and comorbid psychiatric disorders. About 178 participants (104 female, M[SD]age = 21.7[4.6]) with a wide range of psychopathology symptoms completed a modified version of the Eriksen flanker task and symptom questionnaires. Residualized difference values between correct and error trials for delta/theta power and error/correct ERN amplitude were used as dependent variables. Linear regression analyses adjusted for age, sex, and task accuracy showed nonsignificant associations of symptom dimension measures with error-related residualized delta/theta power or residualized ERN amplitude. Subset analyses on those with confirmed psychopathology diagnoses also did not predict residualized error-related delta/theta power nor residualized ERN amplitude (nGAD = 14, nMDD = 28, nComorbid = 19, nControl = 85). Taken in the context of the previous literature, results suggest a heterogeneous relationship between depressive and anxiety symptom dimensions and neurophysiological indices of error-monitoring.

Error-monitoring processes may be affected by transdiagnostic dimensions of psychopathology symptoms including trait anxiety, worry, and severity of depressive symptoms. We tested the relationship between continuous measures of anxiety and depressive symptomology and neural correlates of error-monitoring as measured by time-frequency domain delta and theta oscillatory power and time domain error-related negativity (ERN) amplitude extracted from the electroencephalogram (EEG). Secondary analyses tested for diagnostic group differences in error-related neural responses in individuals with generalized anxiety disorder (GAD), major depressive disorder (MDD), and comorbid psychiatric disorders. 178 participants (104 female, M[SD]age = 21.7[4.6]) with a wide range of psychopathology symptoms completed a modified version of the Eriksen flanker task and symptom questionnaires. Residualized difference values between correct and error trials for delta/theta power and error/correct ERN amplitude were dependent variables. Linear regression analyses adjusted for age and sex showed nonsignificant associations of symptom dimension measures with error-related residualized delta/theta power or residualized ERN amplitude. Subset analyses on those with confirmed psychopathology diagnoses also did not predict residualized error-related delta/theta power nor ERN amplitude. Exploratory analyses with only error trial delta/theta power and ERN amplitude also revealed nonsignificant relationships. Taken in the context of previous literature, results suggest a heterogeneous relationship between depressive and anxiety symptom dimensions and neurophysiological indices of error-monitoring.Impact StatementIn line with the RDoC framework, we tested the relationship between anxiety and depressive symptom dimensions and neural indices of error-processing (delta and theta power, error-related negativity ERP amplitude) in 178 participants with a range of pathology symptoms. A non-significant relationship emerged between neural and symptom measures suggesting anxiety and depressive symptomology have a nuanced relationship with error-monitoring in a large sample across a range of anxiety and depression symptoms.

A cognitive intervention that may reduce weight and caloric intake is inhibitory control training (ICT; having individuals repeatedly withhold dominant responses to unhealthy food images). We conducted a randomized controlled trial where 100 individuals with overweight or obesity were assigned to complete a generic (n = 48) or food-specific ICT (n = 52) training four times per week for four weeks. Weight and caloric intake were obtained at baseline, four-weeks, and 12-weeks. Participants also completed high-calorie and neutral go/no-go tasks while N2 event-related potential (ERP) data, a neural indicator of inhibitory control, was measured at all visits. Results from mixed model analyses indicate that neither weight, caloric intake, nor N2 ERP component amplitude towards high-calorie foods changed at post-testing or at the 12-week follow up. Regression analyses suggest that individuals with smaller N2 difference amplitudes to food may show greater weight loss and reductions in caloric intake after a generic ICT, while individuals with larger N2 difference amplitudes to food may show greater weight loss and reductions in caloric intake after a food-specific ICT. Overall, multiple food-specific or generic ICT sessions over the course of a four-week period do not affect overall weight loss, caloric intake, or N2 ERP amplitude.

The impact of individual differences on performance monitoring and psychopathology is a question of active debate. Personality traits associated with psychopathology may be related to poor internal performance monitoring (as measured by the error-related negativity [ERN]) but intact external performance monitoring (as measured by the reward positivity [RewP]), suggesting that there are underlying neural differences between internal and external performance monitoring processes. We tested the relationships between individual difference measures of perfectionism, locus of control, and ERN, Pe, and RewP component difference amplitude in a healthy undergraduate sample. A total of 128 participants (69 female, M(SD)age= 20.6(2.0) years) completed two tasks: a modified version of the Eriksen Flanker and a doors gambling task along with the Frost Multidimensional Perfectionism scale, the Rotter Locus of Control scale, and the Levenson Multidimensional Locus of Control scale to quantify perfectionism and locus of control traits, respectively. Linear regressions adjusting for age and gender showed that neither ΔERN nor ΔRewP amplitude were significantly moderated by perfectionism or locus of control scores. Findings suggest that, in psychiatrically-healthy individuals, there is not a strong link between perfectionism, locus of control, and ERN or RewP amplitude. Future research on individual difference measures in people with psychopathology may provide further insight into how these personality traits affect performance monitoring.