Reliability of clinical judgment for evaluation of informed consent in mental health settings and the validation of the Evaluation of Informed Consent to Treatment (EICT) scale.

Introduction: The competence assessment to give informed consent in the legal and healthcare settings is often performed merely through clinical judgment. Given the acknowledged limited reliability of clinician-based evaluation in the mental health sector, particularly for the assessment of competence to consent, our objective was to ascertain the dependability of clinical judgment when evaluating the ability of schizophrenia patients to make choices about their health. Methods: The potential convergence between clinical evaluation and scores from a new standardized assessment (the "Evaluation of Informed Consent to Treatment" - "EICT" scale) was therefore tested. The scale assesses four dimensions of competence, specifically how patients normally understand information relating to care (Understanding); how they evaluate the choice of treatment in terms of risk/benefit ratio (Evaluating); how they reason coherently in the decision-making process (Reasoning); and, finally, their ability to make a choice between treatment alternatives (Expressing a choice). Thirty-four outpatients with schizophrenia were evaluated for their competence to consent by five referring clinicians with different backgrounds (psychiatrist, forensic psychiatrist, geriatrician, anesthetist, and medico-legal doctor). Inter-raters variability was tested through correlation analyses between the scores obtained by the clinicians on a modified version of the Global Assessment of Functioning scale (GAF) designed specifically to subjectively assess functioning in each of the four competence dimensions. Two validated competence scales (Mac-CAT-T, SICIATRI-R), and a neuropsychological battery were also administered along with scales for evaluating neuropsychiatric symptoms severity and side effects of medication. Results: Clinical judgments of the individual specialists showed great inter-rater variability. Likewise, only weak/non-significant correlations were found between the EICT subscales and the respective clinicians-rated GAF scales. Conversely, solid correlations were found between the EICT and MacCAT-T subscales. As expected, healthy controls performed better in the ability to give informed consent to treatment, as measured by the three scales (i.e., EICT, MacCAT-T, and SICIATRI-R), and neuropsychological test performance. In the comparisons between patients who, according to the administered EICT, were able or not able to give informed consent to treatment, significant differences emerged for the Phonemic verbal fluency task (p = 0.038), Verbal judgments (p = 0.048), MacCAT-T subscales, and SICIATRI-R total score. Moreover, EICT exhibited excellent internal consistency (Cronbach's alphas ranging from 0.96 to 0.98 for the four subscales) while the Item Analysis, by measuring the correlation between each item of the EICT and the total score, was excellent for all items of all subscales (alphas ranging from 0.86 to 0.98). Discussion: In conclusion, our findings highlighted that the assessment of competence exclusively through clinical judgment is not fully reliable and needs the support of standardized tools. The EICT scale could therefore be useful in assessing general competence to consent both in healthcare and legal contexts, where it might be necessary to evaluate the effective competence of patients with psychiatric disorders. Finally, this scale could serve as a valuable tool for decisions regarding whether and to what extent a patient needs support.

Estimating multimodal brain variability in schizophrenia spectrum disorders: A worldwide ENIGMA study.

Objective: Schizophrenia is a multifaceted disorder associated with structural brain heterogeneity. Despite its relevance for identifying illness subtypes and informative biomarkers, structural brain heterogeneity in schizophrenia remains incompletely understood. Therefore, the objective of this study was to provide a comprehensive insight into the structural brain heterogeneity associated with schizophrenia. Methods: This meta- and mega-analysis investigated the variability of multimodal structural brain measures of white and gray matter in individuals with schizophrenia versus healthy controls. Using the ENIGMA dataset of MRI-based brain measures from 22 international sites with up to 6139 individuals for a given brain measure, we examined variability in cortical thickness, surface area, folding index, subcortical volume and fractional anisotropy. Results: We found that individuals with schizophrenia are distinguished by higher heterogeneity in the frontotemporal network with regard to multimodal structural measures. Moreover, individuals with schizophrenia showed higher homogeneity of the folding index, especially in the left parahippocampal region. Conclusions: Higher multimodal heterogeneity in frontotemporal regions potentially implies different subtypes of schizophrenia that converge on impaired frontotemporal interaction as a core feature of the disorder. Conversely, more homogeneous folding patterns in the left parahippocampal region might signify a consistent characteristic of schizophrenia shared across subtypes. These findings underscore the importance of structural brain variability in advancing our neurobiological understanding of schizophrenia, and aid in identifying illness subtypes as well as informative biomarkers.

Narrative discourse production in Parkinson's disease: Decoupling the role of cognitive-linguistic and motor speech changes.

Introduction: the interplay between neuropsychological and communicative abilities in Parkinson's disease (PD) has been relatively overlooked, and it is not entirely understood which difficulties are consequent to impaired motor control, and which have a linguistic/cognitive basis. Here, we examined narrative discourse in PD using a multi-level analysis procedure considering sentence-level (productivity, lexical-grammatical processing) and discourse-level processes (narrative organization, informativeness), and partialling out patients' motor speech impairments. The interaction between cognitive (i.e. linguistic and executive) and communication abilities was also investigated. Methods: Twenty-nine PD subjects in the mild stage of the disease were compared to 29 matched healthy comparators (HC) on quantitative measures of narrative discourse derived from two picture description tasks. Multivariate (considering articulation rate and educational attainment as covariates) and univariate (with group membership as independent variable) analyses of variance were conducted on separate linguistic domains. The contribution of executive/linguistic abilities to PD's narrative performance was explored by multiple regression analyses on narrative measures significantly differentiating patients from HC. Results: significant reductions in patients were observed on measures of productivity (less well-formed words, shorter sentences) and informativeness (fewer conceptual units, less informative elements, lower number of details) and these alterations were explained by variations in linguistic abilities (action and object naming) rather than executive abilities. Articulation rate and educational attainment did not impact the observed reduced productivity and under-informativeness. Conclusion: referential narrative discourse is altered in PD, regardless of motor impairments in speech production. The observed reductions in productivity/informativeness aspects of narratives were related to naming abilities and in particular to verbs processing, consistently with the neurocognitive model of motor language coupling. Since narratives are amenable to recurrent and automated analysis for the identification of linguistic patterns potentially anticipating the development of PD and the onset of cognitive deterioration, discourse abilities should be quantitatively and repeatedly profiled in the disorder.

Cortical morphology in patients with the deficit and non-deficit syndrome of schizophrenia: a worldwide meta- and mega-analyses.

Converging evidence suggests that schizophrenia (SZ) with primary, enduring negative symptoms (i.e., Deficit SZ (DSZ)) represents a distinct entity within the SZ spectrum while the neurobiological underpinnings remain undetermined. In the largest dataset of DSZ and Non-Deficit (NDSZ), we conducted a meta-analysis of data from 1560 individuals (168 DSZ, 373 NDSZ, 1019 Healthy Controls (HC)) and a mega-analysis of a subsampled data from 944 individuals (115 DSZ, 254 NDSZ, 575 HC) collected across 9 worldwide research centers of the ENIGMA SZ Working Group (8 in the mega-analysis), to clarify whether they differ in terms of cortical morphology. In the meta-analysis, sites computed effect sizes for differences in cortical thickness and surface area between SZ and control groups using a harmonized pipeline. In the mega-analysis, cortical values of individuals with schizophrenia and control participants were analyzed across sites using mixed-model ANCOVAs. The meta-analysis of cortical thickness showed a converging pattern of widespread thinner cortex in fronto-parietal regions of the left hemisphere in both DSZ and NDSZ, when compared to HC. However, DSZ have more pronounced thickness abnormalities than NDSZ, mostly involving the right fronto-parietal cortices. As for surface area, NDSZ showed differences in fronto-parietal-temporo-occipital cortices as compared to HC, and in temporo-occipital cortices as compared to DSZ. Although DSZ and NDSZ show widespread overlapping regions of thinner cortex as compared to HC, cortical thinning seems to better typify DSZ, being more extensive and bilateral, while surface area alterations are more evident in NDSZ. Our findings demonstrate for the first time that DSZ and NDSZ are characterized by different neuroimaging phenotypes, supporting a nosological distinction between DSZ and NDSZ and point toward the separate disease hypothesis.

The functional connectome in obsessive-compulsive disorder: resting-state mega-analysis and machine learning classification for the ENIGMA-OCD consortium.

Current knowledge about functional connectivity in obsessive-compulsive disorder (OCD) is based on small-scale studies, limiting the generalizability of results. Moreover, the majority of studies have focused only on predefined regions or functional networks rather than connectivity throughout the entire brain. Here, we investigated differences in resting-state functional connectivity between OCD patients and healthy controls (HC) using mega-analysis of data from 1024 OCD patients and 1028 HC from 28 independent samples of the ENIGMA-OCD consortium. We assessed group differences in whole-brain functional connectivity at both the regional and network level, and investigated whether functional connectivity could serve as biomarker to identify patient status at the individual level using machine learning analysis. The mega-analyses revealed widespread abnormalities in functional connectivity in OCD, with global hypo-connectivity (Cohen's d: -0.27 to -0.13) and few hyper-connections, mainly with the thalamus (Cohen's d: 0.19 to 0.22). Most hypo-connections were located within the sensorimotor network and no fronto-striatal abnormalities were found. Overall, classification performances were poor, with area-under-the-receiver-operating-characteristic curve (AUC) scores ranging between 0.567 and 0.673, with better classification for medicated (AUC = 0.702) than unmedicated (AUC = 0.608) patients versus healthy controls. These findings provide partial support for existing pathophysiological models of OCD and highlight the important role of the sensorimotor network in OCD. However, resting-state connectivity does not so far provide an accurate biomarker for identifying patients at the individual level.

Brain Network Topology in Deficit and Non-Deficit Schizophrenia: Application of Graph Theory to Local and Global Indices.

Patients with deficit schizophrenia (SZD) suffer from primary and enduring negative symptoms. Limited pieces of evidence and neuroimaging studies indicate they differ from patients with non-deficit schizophrenia (SZND) in neurobiological aspects, but the results are far from conclusive. We applied for the first time, graph theory analyses to discriminate local and global indices of brain network topology in SZD and SZND patients compared with healthy controls (HC). High-resolution T1-weighted images were acquired for 21 SZD patients, 21 SZND patients, and 21 HC to measure cortical thickness from 68 brain regions. Graph-based metrics (i.e., centrality, segregation, and integration) were computed and compared among groups, at both global and regional networks. When compared to HC, at the regional level, SZND were characterized by temporoparietal segregation and integration differences, while SZD showed widespread alterations in all network measures. SZD also showed less segregated network topology at the global level in comparison to HC. SZD and SZND differed in terms of centrality and integration measures in nodes belonging to the left temporoparietal cortex and to the limbic system. SZD is characterized by topological features in the network architecture of brain regions involved in negative symptomatology. Such results help to better define the neurobiology of SZD (SZD: Deficit Schizophrenia; SZND: Non-Deficit Schizophrenia; SZ: Schizophrenia; HC: healthy controls; CC: clustering coefficient; L: characteristic path length; E: efficiency; D: degree; CCnode: CC of a node; CCglob: the global CC of the network; Eloc: efficiency of the information transfer flow either within segregated subgraphs or neighborhoods nodes; Eglob: efficiency of the information transfer flow among the global network; FDA: Functional Data Analysis; and Dmin: estimated minimum densities).

Individual differences among older adults with mild and moderate dementia in social and emotional loneliness and their associations with cognitive and psychological functioning.

BACKGROUND: Loneliness is a major health issue among older adults. The aim of this study was to assess the relationship between loneliness, in its social and emotional facets, and the cognitive (language), and behavioral/psychological functioning as well as quality of life (QoL) in people with mild and moderate dementia, i.e., considering dementia severity as an individual characteristic. METHODS: This cross-sectional study involved 58 people with mild dementia and 55 people with moderate dementia. Participants completed the Social and Emotional Loneliness scale, along with measures assessing their language skills, the frequency and severity of their behavioral and psychological symptoms, and their QoL. RESULTS: Socio-demographic characteristics and depression, but not loneliness or its social and emotional facets, contributed to explain participants' behavioral and psychological symptoms, regardless of dementia severity. Loneliness explained, though to a small extent (8% of variance), language skills in people with moderate dementia, with social loneliness only accounting for language skills (18% of variance) in this group. Loneliness also modestly accounted for dysphoria symptoms in both the mildly and moderately impaired (6% and 5% of variance, respectively) individuals with social loneliness predicting dysphoric mood in the former group only (7% of variance). Loneliness also explained, to a larger extent, QoL in both the mildly impaired and moderately impaired individuals (27% and 20% of variance, respectively), its social facet predicting QoL in the mildly impaired (30% of variance), and its emotional facet in the moderately impaired (21% of variance) group. CONCLUSION: These findings suggest that loneliness and its facets have a clear impact on perceived QoL, and influence the language skills and dysphoria symptoms of people with dementia, to a degree that depends on dementia severity. The assessment of loneliness and its facets in people with dementia considering dementia severity, and the promotion of social inclusion to reduce it should be considered by professionals.

Preoperative Navigated Transcranial Magnetic Stimulation: New Insight for Brain Tumor-Related Language Mapping.

Preoperative brain mapping methods are particularly important in modern neuro-oncology when a tumor affects eloquent language areas since damage to parts of the language circuits can cause significant impairments in daily life. This narrative review examines the literature regarding preoperative and intraoperative language mapping using repetitive navigated transcranial magnetic stimulation (rnTMS) with or without direct electrical stimulation (DES) in adult patients with tumors in eloquent language areas. The literature shows that rnTMS is accurate in detecting preexisting language disorders and positive intraoperative mapping regions. In terms of the region extent and clinical outcomes, rnTMS has been shown to be accurate in identifying positive sites to guide resection, reducing surgery duration and craniotomy size and thus improving clinical outcomes. Before incorporating rnTMS into the neurosurgical workflow, the refinement of protocols and a consensus within the neuro-oncology community are required.

Internal clock variability, mood swings and working memory in bipolar disorder.

BACKGROUND: Distortions in time processing may be regarded as an endophenotypic marker of neuropsychiatric diseases; however, investigations addressing Bipolar Disorder (BD) are still scarce. METHODS: The present study compared timing abilities in 30 BD patients and 30 healthy controls (HC), and explored the relationship between time processing and affective-cognitive symptoms in BD, with the aim to determine whether timing difficulties are primary in bipolar patients or due to comorbid cognitive impairment. Four tasks measuring external timing were administered: a temporal and spatial orienting of attention task and a temporal and colour discrimination task, for assessing the ability to evaluate temporal properties of external events; two other tasks assessed the speed of the internal clock (i.e. temporal bisection and temporal production tasks). Attentional, executive and working memory (WM) demands were equated for controlling additional cognitive processes. RESULTS: BD patients did not show differences in external timing accuracy compared to HC; conversely, we found increased variability of the internal clock in BD and this performance was related to Major Depressive Episodes recurrence and WM functioning. Hence, variability of the internal clock is influenced by the progressive course of BD and impacted by variations in WM. LIMITATIONS: Future studies including BD patients stratified by mood episode will further specify timing alterations conditional to the current affective state. CONCLUSIONS: Our results shed new light on the clinical phenotypes of BD, suggesting that timing might be used as a model system of the ongoing pathophysiological process.

Brain Metabolism and Amyloid Load in Individuals With Subjective Cognitive Decline or Pre-Mild Cognitive Impairment.

BACKGROUND AND OBJECTIVE: Multicenter study aiming at investigating the characteristics of cognitive decline, neuropsychiatric symptoms, and brain imaging in individuals with subjective cognitive decline (SCD) and subtle cognitive decline (pre-Mild Cognitive Impairment, pre-MCI). METHODS: Data were obtained from the Network-AD project (NET-2011-02346784). The included subjects underwent baseline cognitive and neurobehavioral evaluation, FDG-PET, and, amyloid-PET. We used Principal Component Analysis (PCA) to identify independent neuropsychological and neuropsychiatric dimensions and their association with brain metabolism. RESULTS: A total of 105 subjects (SCD=49, pre-MCI=56) were included. FDG-PET was normal in 45% of subjects and revealed brain hypometabolism in 55%, with a frontal-like pattern as the most frequent finding (28%). Neuropsychiatric symptoms emerging from the Neuropsychiatric Inventory and the Starkstein Apathy Scale were highly prevalent in the whole sample (78%). An abnormal amyloid load was detected in the 18% of the subjects that underwent amyloid-PET (n=60). PCA resulted in three neuropsychological factors: 1) executive/visuo-motor, correlating with hypometabolism in frontal, occipital cortices and basal ganglia; 2) memory, correlating with hypometabolism in temporo-parietal regions; 3) visuo-spatial/constructional, correlating with hypometabolism in fronto-parietal cortices. Two factors emerged from the neuropsychiatric PCA: 1) affective, correlating with hypometabolism in orbito-frontal, cingulate cortex, insula; 2) hyperactive/psychotic, correlating with hypometabolism in frontal, temporal and parietal regions. DISCUSSION: FDG-PET evidence suggests either normal brain function or different patterns of brain hypometabolism in SCD and pre-MCI subjects. These results indicate that SCD and pre-MCI represent heterogeneous populations. Consistently, different neuropsychological and neuropsychiatric profiles emerged, which correlated with neuronal dysfunction in specific brain regions. Long-term follow-up studies are needed to assess the risk of progression to dementia in these conditions.

Dysfunctional Beliefs and Cognitive Performance across Symptom Dimensions in Childhood and Adolescent OCD.

Although etiological and maintenance cognitive factors have proved effective in predicting the disease course in youths with OCD, their contribution to symptom severity and specific OCD dimensions has been scarcely examined. In a cohort of children and adolescents with OCD (N = 41; mean age = 14; age range = 10-18 yrs.), we investigated whether certain dysfunctional beliefs and cognitive traits could predict symptom severity, and whether they were differentially associated with specific symptom dimensions. We found that self-oriented and socially prescribed perfectionism and intolerance to uncertainty were associated with higher obsession severity, which was not uniquely related to any neuropsychological variable. Greater severity of obsessions and compulsions about harm due to aggression/injury/violence/natural disasters was predicted by excessive concerns with the expectations of other people. Severity in this dimension was additionally predicted by decreasing accuracy in performing a problem-solving, non-verbal reasoning task, which was also a significant predictor of severity of obsessions about symmetry and compulsions to count or order/arrange. Apart from corroborating both the belief-based and neuropsychological models of OCD, our findings substantiate for the first time the specificity of certain dysfunctional beliefs and cognitive traits in two definite symptom dimensions in youth. This bears important clinical implications for developing treatment strategies to deal with unique dysfunctional core beliefs, and possibly for preventing illness chronicity.

A meta-analysis of deep brain structural shape and asymmetry abnormalities in 2,833 individuals with schizophrenia compared with 3,929 healthy volunteers via the ENIGMA Consortium.

Schizophrenia is associated with widespread alterations in subcortical brain structure. While analytic methods have enabled more detailed morphometric characterization, findings are often equivocal. In this meta-analysis, we employed the harmonized ENIGMA shape analysis protocols to collaboratively investigate subcortical brain structure shape differences between individuals with schizophrenia and healthy control participants. The study analyzed data from 2,833 individuals with schizophrenia and 3,929 healthy control participants contributed by 21 worldwide research groups participating in the ENIGMA Schizophrenia Working Group. Harmonized shape analysis protocols were applied to each site's data independently for bilateral hippocampus, amygdala, caudate, accumbens, putamen, pallidum, and thalamus obtained from T1-weighted structural MRI scans. Mass univariate meta-analyses revealed more-concave-than-convex shape differences in the hippocampus, amygdala, accumbens, and thalamus in individuals with schizophrenia compared with control participants, more-convex-than-concave shape differences in the putamen and pallidum, and both concave and convex shape differences in the caudate. Patterns of exaggerated asymmetry were observed across the hippocampus, amygdala, and thalamus in individuals with schizophrenia compared to control participants, while diminished asymmetry encompassed ventral striatum and ventral and dorsal thalamus. Our analyses also revealed that higher chlorpromazine dose equivalents and increased positive symptom levels were associated with patterns of contiguous convex shape differences across multiple subcortical structures. Findings from our shape meta-analysis suggest that common neurobiological mechanisms may contribute to gray matter reduction across multiple subcortical regions, thus enhancing our understanding of the nature of network disorganization in schizophrenia.

Corpus callosum morphology in major mental disorders: a magnetic resonance imaging study.

Mental disorders diagnosis is based on specific clinical criteria. However, clinical studies found similarities and overlapping phenomenology across a variety of disorders, which suggests a common neurobiological substrate. Thus, there is a need to measure disease-related neuroanatomical similarities and differences across conditions. While structural alterations of the corpus callosum have been investigated in obsessive-compulsive disorder, schizophrenia, major depressive disorder and bipolar disorder, no study has addressed callosal aberrations in all diseases in a single study. Moreover, results from pairwise comparisons (patients vs. controls) show some inconsistencies, possibly related to the parcellation methods to divide the corpus callosum into subregions. The main aim of the present paper was to uncover highly localized callosal characteristics for each condition (i.e. obsessive-compulsive disorder, schizophrenia, major depressive disorder and bipolar disorder) as compared either to healthy control subjects or to each other. For this purpose, we did not rely on any sub-callosal parcellation method, but applied a well-validated approach measuring callosal thickness at 100 equidistant locations along the whole midline of the corpus callosum. One hundred and twenty patients (30 in each disorder) as well as 30 controls were recruited for the study. All groups were closely matched for age and gender, and the analyses were performed controlling for the impact of antipsychotic treatment and illness duration. There was a significant main effect of group along the whole callosal surface. Pairwise post hoc comparisons revealed that, compared to controls, patients with obsessive-compulsive disorder had the thinnest corpora callosa with significant effects almost on the entire callosal structure. Patients with schizophrenia also showed thinner corpora callosa than controls but effects were confined to the isthmus and the anterior part of the splenium. No significant differences were found in both major depressive disorder and bipolar disorder patients compared to controls. When comparing the disease groups to each other, the corpus callosum was thinner in obsessive-compulsive disorder patients than in any other group. The effect was evident across the entire corpus callosum, with the exception of the posterior body. Altogether, our study suggests that the corpus callosum is highly changed in obsessive-compulsive disorder, selectively changed in schizophrenia and not changed in bipolar disorder and major depressive disorder. These results shed light on callosal similarities and differences among mental disorders providing valuable insights regarding the involvement of the major brain commissural fibre tract in the pathophysiology of each specific mental illness.

Later life depression as risk factor for developing dementia: epidemiological evidence, predictive models, preventive strategies and future trends.

Current investigations in pre-symptomatic dementia have suggested that depressive mood, a treatable condition, may play an important role in the development of the disorder. However, whether depression in adulthood constitute a risk factor, or a prodrome of dementia remains unclear. A major implication in such dispute is the analytic framework used to identify putative risk factors. Indeed, if evaluated in the years immediately prior to dementia diagnosis the association between depression and dementia may reflect depressive symptoms as a prodrome of yet-undiagnosed dementia. Unfortunately, long term prospective cohort investigations, reaching back into the preclinical phase of dementia are sparse. Here, we have surveyed high-quality evidence (systematic reviews and meta-analyses) on the association between depressive symptoms and increased odds of dementia. Meta-analytic findings are also presented and discussed regarding depression as a prodromal stage of dementia, or a consequence of underlying neurodegenerative processes. Additionally, the potential confounding effect of several variables on the risk association between depression and dementia, an aspect hardly investigated, is discussed. While early onset late-life depression - defined as starting before 60 years of age - increases the odds of developing dementia in predisposed subjects, late-onset depression appears to be a prodrome and a clear accelerating factor for cognitive deterioration. Since it is increasingly important to consider the potential of preemptive approaches to decrease the impact of dementia, evidence on potentially effective preventive strategies targeting depression as a risk factor, and next steps in further research are presented as concluding remarks.

Performance-Based Everyday Problem-Solving in Patients With TBI.

OBJECTIVE: The present study examined whether the everyday problems test (EPT), a performance-based measure of everyday problem-solving, can be considered a useful test in assessing functional independence in patients with traumatic brain injury (TBI). The relationship between EPT, cognitive abilities (i.e., selective attention, set switching, and working memory) and self-rated measures of everyday functioning and disability in these patients was also assessed. METHOD: In this case-control study 25 postcomatose outpatients with TBI (age M = 35.9, SD = 14.21) from a neurorehabilitation unit and 25 matched controls were enrolled. Participants were administered the EPT along with neuropsychological tests of selective attention, set switching and working memory, and self-rated measures of everyday functioning and disability. RESULTS: Patients with TBI were less accurate and slower than controls in the EPT; the two groups were accurately classified based on EPT completion time (likelihood ratio test χ2 = 28.67, R2 = 0.72, p < .001). In the patient group education and selective attention explained a large portion of variance in EPT accuracy (R2 = 0.53, p = .001), while only selective attention explained a significant portion of variance in EPT time (R2 = 0.24, p < .01). Self-rated measures of everyday functioning and disability did not significantly contribute to EPT performance variance. CONCLUSION: Including performance-based measures as the EPT in a multifactorial approach to assessment can be useful for unraveling cognitive factors contributing to TBI's impact on everyday functioning. Since attentional processes seem to play a significant role in determining EPT performance, rehabilitation of functional independence should target this ability first.

White matter microstructure and its relation to clinical features of obsessive-compulsive disorder: findings from the ENIGMA OCD Working Group.

Microstructural alterations in cortico-subcortical connections are thought to be present in obsessive-compulsive disorder (OCD). However, prior studies have yielded inconsistent findings, perhaps because small sample sizes provided insufficient power to detect subtle abnormalities. Here we investigated microstructural white matter alterations and their relation to clinical features in the largest dataset of adult and pediatric OCD to date. We analyzed diffusion tensor imaging metrics from 700 adult patients and 645 adult controls, as well as 174 pediatric patients and 144 pediatric controls across 19 sites participating in the ENIGMA OCD Working Group, in a cross-sectional case-control magnetic resonance study. We extracted measures of fractional anisotropy (FA) as main outcome, and mean diffusivity, radial diffusivity, and axial diffusivity as secondary outcomes for 25 white matter regions. We meta-analyzed patient-control group differences (Cohen's d) across sites, after adjusting for age and sex, and investigated associations with clinical characteristics. Adult OCD patients showed significant FA reduction in the sagittal stratum (d = -0.21, z = -3.21, p = 0.001) and posterior thalamic radiation (d = -0.26, z = -4.57, p < 0.0001). In the sagittal stratum, lower FA was associated with a younger age of onset (z = 2.71, p = 0.006), longer duration of illness (z = -2.086, p = 0.036), and a higher percentage of medicated patients in the cohorts studied (z = -1.98, p = 0.047). No significant association with symptom severity was found. Pediatric OCD patients did not show any detectable microstructural abnormalities compared to controls. Our findings of microstructural alterations in projection and association fibers to posterior brain regions in OCD are consistent with models emphasizing deficits in connectivity as an important feature of this disorder.