There is accumulating evidence for the role of fronto-striatal and associated circuits in obsessive-compulsive disorder (OCD) but limited and conflicting data on alterations in cortical thickness.
To ...investigate alterations in cortical thickness and subcortical volume in OCD.
In total, 412 patients with OCD and 368 healthy adults underwent magnetic resonance imaging scans. Between-group analysis of covariance of cortical thickness and subcortical volumes was performed and regression analyses undertaken.
Significantly decreased cortical thickness was found in the OCD group compared with controls in the superior and inferior frontal, precentral, posterior cingulate, middle temporal, inferior parietal and precuneus gyri. There was also a group × age interaction in the parietal cortex, with increased thinning with age in the OCD group relative to controls.
Our findings are partially consistent with earlier work, suggesting that group differences in grey matter volume and cortical thickness could relate to the same underlying pathology of OCD. They partially support a frontostriatal model of OCD, but also suggest that limbic, temporal and parietal regions play a role in the pathophysiology of the disorder. The group × age interaction effects may be the result of altered neuroplasticity.
Neurotoxicity associated with the antiretroviral efavirenz (EFV) has been documented in HIV-infected adults, but there are no data on the impact of EFV on brain function in adolescents. We ...investigated potential alterations in fronto-striatal function associated with EFV use in adolescents. A total of 86 adolescents underwent a Stop Signal Anticipation Task (SSAT) during functional MRI (fMRI), 39 HIV+ adolescents receiving EFV, 27 HIV+ adolescents on antiretroviral therapy without EFV (matched on age, gender, education, CD4 cell count and HIV viral load) and 20 HIV− matched controls (matched on age and gender). The task required participants to give timed GO responses with occasional STOP signals at fixed probabilities. Reactive inhibition was modelled as a correct STOP response and proactive inhibition was modelled after response slowing as the STOP probability increases. A priori mask-based regions associated with reactive and proactive inhibition were entered into two respective multivariate ANOVAs. The EFV treatment group showed significantly blunted proactive inhibitory behavioural responses compared to HIV+ adolescents not receiving EFV. There was no difference in reactive inhibition between treatment groups. We also demonstrated a significant effect of EFV treatment on BOLD signal in proactive inhibition regions. There was no difference in regions involved in reactive inhibition. We found no differences between adolescents not receiving EFV and HIV− controls, showing that functional and behavioural differences were unique to the EFV group. Here, we demonstrate for the first time a potential adverse impact of EFV on higher cortical function in young HIV+ adolescents.
Background
Parkinson’s disease (PD) is heterogeneous, both phenotypically and in terms of temporal progression. The Hoehn and Yahr (HY) scale is a well‐established PD staging approach, and identifies ...5 stages of the disease. Morphometric effects in deep gray matter regions of the brain associated with HY stages are complex; a recent large‐scale ENIGMA‐PD study showed higher local subcortical volumes in early HY stages relative to controls, followed by a precipitous decrease after stage 2 1. This finding motivates a closer look at fine‐level morphometry beyond gross volume measures. Here, we developed and applied a novel machine learning algorithm to reveal the subcortical shape signatures of HY staging.
Method
We computed shape features in 7 bilateral subcortical regions 2 based on T1‐weighted MRI data from 2,322 PD subjects and 1,207 controls from 20 ENIGMA‐PD cohorts (HY stages in Table 1). We developed a sparse, spatially coherent (total variation/TV‐L1) ordinal linear logistic classifier 3 to predict HY stages with a single linear model. We applied the model to vertex‐wise medial thickness features. We optimized regularization parameters for balanced recall (sensitivity) and precision using a 4‐fold cross‐validation grid search. Very low numbers of HY4 and HY5 samples necessitated merging stages 3‐5 into one category. For comparison, we also trained 4 binary TV‐L1 logit models on the same features 4, discriminating (1) PD‐Control; (2) HY1‐HY2; (3) HY1‐HY345; (4) HY2‐HY345, using ROC area‐under‐the‐curve (AUC) evaluation.
Result
Across‐stage mean out‐of‐sample precision and recall were 0.43, and 0.393, respectively (chance=0.33). Table 2 shows the confusion matrix and precision/recall for each HY stage. All models’ linear coefficient maps are displayed in Figures 1,2. Binary classification ROC‐AUC was 0.66 for PD‐Control, and ranged from 0.62 to 0.73 for HY prediction (Figure 2).
Conclusion
We developed an ordit machine learning model for morphometric shape‐based ordinal classification of disease stages, training it for Parkinson’s Disease Hoehn and Yahr stage prediction on a large MRI collection. Performance was substantially above chance. Model weight maps indicate early increased thalamic thickness, followed by a complex thinning pattern associated with later HY stages.
Background: Social Anxiety Disorder (SAD) is a disabling psychiatric disorder, associated with high co-morbidity. Previous research on structural brain alterations associated with SAD has yielded ...inconsistent results concerning changes in gray matter (GM) in various brain regions, as well as on the relationship between GM and SAD-symptomatology. These heterogeneous findings are possibly due to limited sample sizes. Multi-site imaging offers new possibilities to investigate SAD-related GM changes in larger samples.
Methods: An international multi-center mega-analysis on the largest database of SAD brain scans to date was performed to compare GM volumes of SAD-patients (n=174) and healthy participants (n=213) using voxel-based morphometry. A hypothesis-driven region of interest (ROI) approach was used, focusing on the basal ganglia, amygdala-hippocampal complex, prefrontal cortex and parietal cortex.
Results: SAD-patients had larger GM volume in the dorsal striatum when compared to healthy participants. This increase correlated positively with the level of social anxiety symptoms. No SAD-related differences in GM volume were present in the other ROIs.
Conclusions: The results suggest a role for the dorsal striatum in SAD, but previously reported SAD-related changes in GM in the amygdala, hippocampus, precuneus, prefrontal cortex and parietal regions were not replicated. Thereby, our findings indicate that sample size matters and stress the need for meta-analyses like those performed by the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium and its working groups. Actually, the collaborative effort for this work has resulted in the start of the ENIGMA-Anxiety workgroup.
To examine hippocampal volume and white matter tracts in women with and without intimate partner violence (IPV).
Nineteen women with IPV exposure in the last year, and 21 women without IPV exposure ...in the last year underwent structural magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) sequences. Additional data on alcohol use and presence of psychiatric disorder was collected. Differences in fractional anisotropy (FA) between the two groups were examined, using a statistical model that included demographic measures, alcohol use and psychiatric disorder.
IPV subjects did not demonstrate significantly different hippocampal volumes compared to subjects without recent IPV. FA was, however, significantly reduced in the body of the corpus callosum of IPV subjects. Adjusting for age, alcohol use, smoking and psychiatric diagnosis did not change the significance of the result.
Data on hippocampal volume in IPV are inconsistent, perhaps reflecting the fact that multiple factors influence this measure. Reduced FA in the body of the corpus callosum in IPV suggests altered integrity of this white matter tract; additional work is needed to address the underlying mechanisms and clinical correlates of this finding.
Aims In patients with acute myocardial infarction (MI), mortality can be predicted by risk scoring systems, but the impact of therapy recommended by guidelines is poorly documented. The aim of this ...study was to determine, taking into account the patient's condition at admission, to what extent the degree of guideline compliance influences the 1-year survival of patients admitted for acute MI. Methods and results A 6-month registry was carried out in a geographically limited area, prospectively including all patients with acute MI. A risk score based on initial presentation, and a compliance index based on patient characteristics, type of MI, in-hospital management (including revascularization strategies and use of recommended drugs) were established. Patients were clinically followed at 1 year. A total of 754 patients, 333 ST elevation MI and 421 non-ST elevation MI, were included. The median compliance index (percentage of optimal compliance with guidelines) was 0.66 (95% CI 0.5;8.3). One-year mortality rate was 11.5%. By logistic regression, three variables were independently related to mortality: type of MI OR=2.6 (1.5;4.3), risk score OR=2.4 (1.9;3.1) per additional 10%, and compliance index OR=0.8 (0.7;0.9) per additional 10%. Conclusion A clear relationship between the extent of guideline implementation, and 1-year mortality was shown and this relationship remained strong after stratification on the risk score at admission and the type of MI. These data emphasize the need for thorough implementation of guidelines to improve the outcome of patients suffering from acute MI.
MINDscape is a web based integrated interface to diverse sources of clinical information including both patient specific information (electronic medical record) as well as medical knowledge (the ..."digital library") to provide "just in time" information at the point of care. It was developed at the University of Washington to meet clinical information needs both as identified locally and by a review of the literature. Beta testing by over 600 clinicians is in progress and medical centers wide access scheduled for Fall 1997. We describe the information needs we sought to meet and the ongoing evaluation approach we are taking to ensure the information needs of a diverse group of clinicians are met. The iterative evolution of the interface from prototype, to alpha to large scale beta testing is reported. Integration of information occurs at three levels: integration of information by patient, integration of information by provider, and integration of patient specific information with medical reference material and decision support tools.
Sixteen cases of unilateral and 5 cases of bilateral traumatic renal artery occlusion caused by avulsion or thrombosis are presented. The injury typically follows automobile-pedestrian accidents to ...young male subjects. Associated extrarenal injuries are usual but non-pedicle renal injury is infrequent. Suspicion of the unilateral injury depends upon recognition of absence of visible excretion at urography. The clue to bilateral occlusion is anuria. Diagnosis is confirmed by urgent arteriography. Hematuria was absent in 24 per cent and the injury was missed at laparotomy in 29 per cent of the initial explorations. Renal function was salvaged by arterial reconstruction in 2 cases, 12 hours and 5 months after injury respectively. Hypertension developed in 50 per cent of the cases and was generally mild.
PDF
