Mercury Isotope Fractionation in the Subsurface of a Hg(II) Chloride-Contaminated Industrial Legacy Site.

To understand the transformations of mercury (Hg) species in the subsurface of a HgCl2-contaminated former industrial site in southwest Germany, Hg isotope analysis was combined with an investigation of Hg forms by a four-step sequential extraction protocol (SEP) and pyrolytic thermodesorption. Data from two soil cores revealed that the initial HgCl2 was partly reduced to metallic Hg(0) and that Hg forms of different mobility and oxidation state coexist in the subsurface. The most contaminated sample (K2-8, 802 mg kg-1 Hg) had a bulk δ202Hg value of around -0.43 ± 0.06‰ (2SD), similar to published average values for industrial Hg sources. Other sample signatures varied significantly with depth and between SEP pools. The most Hg-rich samples contained mixtures of Hg(0) and Hg(II) phases, and the water-extractable, mobile Hg pool exhibited heavy δ202Hg values of up to +0.18‰. Sequential water extracts revealed slow dissolution kinetics of mobile Hg pools, continuously releasing isotopically heavy Hg into solution. This was further corroborated by heavy δ202Hg values of groundwater samples. Our results demonstrate that the Hg isotope signature of an industrial contamination source can be significantly altered during the transformations of Hg species in the subsurface, which complicates source tracing applications but offers the possibility of using Hg isotopes as process tracers in contaminated subsurface systems.

A Robust 96.6-dB-SNDR 50-kHz-Bandwidth Switched-Capacitor Delta-Sigma Modulator for IR Imagers in Space Instrumentation.

Infrared imaging technology, used both to study deep-space bodies' radiation and environmental changes on Earth, experienced constant improvements in the last few years, pushing data converter designers to face new challenges in terms of speed, power consumption and robustness against extremely harsh operating conditions. This paper presents a 96.6-dB-SNDR (Signal-to-Noise-plus-Distortion Ratio) 50-kHz-bandwidth fourth-order single-bit switched-capacitor delta-sigma modulator for ADC operating at 1.8 V and consuming 7.9 mW fit for space instrumentation. The circuit features novel Class-AB single-stage switched variable-mirror amplifiers (SVMAs) enabling low-power operation, as well as low sensitivity to both process and temperature deviations for the whole modulator. The physical implementation resulted in a 1.8-mm2 chip integrated in a standard 0.18-µm 1-poly-6-metal (1P6M) CMOS technology, and it reaches a 164.6-dB Schreier figure of merit from experimental SNDR measurements without making use of any clock bootstrapping,analogcalibration,nordigitalcompensationtechnique. Whencoupledtoa2048×2048 IR imager, the current design allows more than 50 frames per minute with a resolution of 16 effective number of bits (ENOB) while consuming less than 300 mW.

Comparing Modeled and Measured Mercury Speciation in Contaminated Groundwater: Importance of Dissolved Organic Matter Composition.

In addition to analytical speciation, reliable Hg species modeling is crucial for predicting the mobility and toxicity of Hg, but geochemical speciation codes have not yet been tested for their prediction accuracy. Our study compares analyses of Hg species in highly Hg-contaminated groundwater (Hgtot: 0.02-4 µmol·L(-1)) at three sites with predictions of Hg speciation obtained from three geochemical codes (WHAM, Visual MINTEQ, PHREEQC) with and without implementation of Hg complexation by dissolved organic matter (DOM). Samples were analyzed for chemical composition, elemental, inorganic, and DOM-bound Hg (Hg(0), Hginorg, HgDOM). Hg-DOM complexation was modeled using three approaches: binding to humic/fulvic acids, binding to thiol-groups, or a combination of both. Results of Hg(0) modeling were poor in all scenarios. Prediction accuracy for Hginorg and HgDOM strongly depended on the assumed DOM composition. Best results were achieved when weaker binding sites, simulated by WHAMs DOM submodel, were combined with strongly binding thiol groups. Indications were found that thiol-DOM ratios in groundwater are likely to be lower than in surface water, highlighting the need for analytical thiol quantification in groundwater DOM. This study shows that DOM quality is a crucial parameter for prediction of Hg speciation in groundwater by means of geochemical modeling.

Potential of Brass to Remove Inorganic Hg(II) from Aqueous Solution through Amalgamation.

Brass shavings (CuZn45) were tested for their efficiency to remove Hg(II) from contaminated groundwater through amalgamation. The study was focused on long-term retention efficiency, the understanding of the amalgamation process and kinetics, and influences of filter surface alteration. Column tests were performed with brass filters (thickness 3 to 9 cm) flushed with 1000 µg/L Hg solution for 8 hours under different flow rates (300 to 600 mL/h). Brass filters consistently removed >98% of Hg from solution independent of filter thickness and flow rate. In a long-term experiment (filter thickness 2 cm), Hg retention decreased from 96 to 92% within 2000 hours. Batch and column experiments for studying kinetics of Hg removal indicate ~100% Hg removal from solution within only 2 hours. Solid-phase mercury thermo-desorption analysis revealed that Hg(0) diffusion into the brass surface controls kinetics of mercury retention. Brass surface alteration could be observed, but did not influence Hg retention.

Computerized neurocognitive test performance in schizophrenia: a lifespan analysis.

OBJECTIVE: Computerized neurocognitive batteries based on advanced behavioral neuroscience methods are increasingly used in large-scale clinical and genomic studies. Favorable construct validity in younger schizophrenia patients has been reported, but not in older patients. New variables afforded by computerized assessments were used to clarify age-associated cognitive impairment across the lifespan. METHODS: 624 patients with schizophrenia and 624 healthy comparison (HC) subjects age 16-75 completed a 1-2-hour computerized neurocognitive battery (CNB) that assessed abstraction and mental flexibility, attention, working memory, recognition memory (verbal, facial, spatial), language, visuospatial, and emotion processing. Linear mixed effects models tested for group differences in accuracy, response time, and efficiency scores. Contrasts were stratified by age. RESULTS: 91% of older (45+) and 94% of younger (< 45) groups provided "good" data quality. After controlling for parental education and project, there were significant three-way interactions for diagnosis x domain x age group on all three outcome variables. Patients performed worse than HC across all neurocognitive domains, except in the oldest group of 60+ patients. Age-stratified analyses did not show differences between younger (16-45) and older patients (45-60, 60+), except for the attention domain. Older patients' reduced working memory efficiency was due to worse speed, not accuracy. Older patients were quicker than younger patients in processing emotions. CONCLUSIONS: Computerized assessments are feasible in large cohorts of schizophrenia patients. There is stable and generalized neurocognitive dysfunction across the lifespan in schizophrenia, albeit with fewer differences in some domains between older patients and HC after age 60. Speed-accuracy tradeoff strategies suggest deceleration of some frontal networks and improvements in speed of emotional processing.

Adjunctive cognitive remediation for schizophrenia using yoga: an open, non-randomized trial.

BACKGROUND: Yoga therapy (YT) improves cognitive function in healthy individuals, but its impact on cognitive function among persons with schizophrenia (SZ) has not been investigated. AIMS: Evaluate adjunctive YT for cognitive domains impaired in SZ. METHODS: Patients with SZ received YT or treatment as usual (TAU; n = 65, n = 23, respectively). Accuracy and speed for seven cognitive domains were assessed using a computerized neurocognitive battery (CNB), thus minimizing observer bias. Separately, YT was evaluated among patients with Bipolar I disorder (n = 40), Major Depressive Disorder (n = 37), and cardiology outpatients (n = 68). All patients also received routine pharmacotherapy. Patients were not randomized to YT or TAU. RESULTS: Compared with the SZ/TAU group, the SZ/YT group showed significantly greater improvement with regard to measures of attention following corrections for multiple comparisons; the changes were more prominent among the men. In the other diagnostic groups, differing patterns of improvements were noted with small to medium effect sizes. CONCLUSIONS: Our initial analyses suggest nominally significant improvement in cognitive function in schizophrenia with adjunctive therapies such as YT. The magnitude of the change varies by cognitive domain and may also vary by diagnostic group.

Computerized neurocognitive profile in young people with 22q11.2 deletion syndrome compared to youths with schizophrenia and at-risk for psychosis.

Adults with 22q11.2 Deletion syndrome (22q11DS) have increased prevalence of schizophrenia features. Our goal is to compare the neurocognitive profile in 22q11DS, schizophrenia and individuals at risk for schizophrenia. Twenty-one 22q11DS patients (8-32 years, mean 14.9 years, 15M, 6F) were matched to four comparison groups on age: low risk (n = 21), first-degree family members of schizophrenia patients (genetic risk, n = 20), individuals exhibiting putatively prodromal symptoms (clinical risk, n = 19), and patients with schizophrenia (n = 21). All participants received semi-structured interviews [Diagnostic Interview for Genetic Studies (DIGS) and the Structured Interview for Prodromal Syndromes (SIPS)], and a computerized neurocognitive battery (CNB) measuring the following domains: Abstraction and Mental Flexibility, Attention, Working Memory, Verbal Memory, Face Memory, Spatial Memory, Language, Spatial Processing, Sensorimotor Dexterity, and Emotion Processing. Sixty percent of 22q11DS participants met SIPS criteria for prodromal symptoms and one participant met criteria for paranoid schizophrenia. Thirty-eight percent met criteria for Depressive Disorders. All 22q11DS participants successfully completed the CNB. 22q11DS participants were significantly less accurate in nearly all domains, but had similar speed of response compared to the other groups. Their profile resembled that of the psychosis groups in accuracy and speed, except for more pronounced deficits in accuracy for face memory and emotion processing. Subthreshold psychotic symptoms are present in a high proportion of 22q11DS participants. Deficits shown in the CNB are more pronounced for accuracy than speed relative to the psychosis groups with similar profiles. Similar deficits have been described in the 22q11DS population using non-computerized measures, which require increased testing time.

Mercury removal from contaminated groundwater: Performance and limitations of amalgamation through brass shavings.

Brass shavings have been proposed as a cost-effective filter material to remove Hg from contaminated groundwater. This method, which is based on the reduction of reactive Hg(II) and subsequent formation of amalgams, has been shown to be fast and effective in the short term. However, the effectiveness of brass filters and their stability over the long term, especially if used in passive filter systems such as permeable reactive barriers (PRB) under high flow conditions, is unknown. To evaluate the performance and limitations of brass shavings for Hg removal from contaminated groundwater, we performed long-term pilot scale filtration tests (6 and 28 months) at two former wood impregnation sites with severe groundwater contamination (up to 870 µg L(-1) Hg). The results showed that even under high flow conditions (>60 m d(-1)), 60-80% of the Hg was removed in the first 8 mm of the brass shavings filter bed. The kinetics of filtration, Hg total removal performance (>99.95%), and loading capacity (164 g L(-1)) surpassed those of a Hg-specific synthetic resin (LEWATIT(®)MonoPlus TP-214). However, under natural pH conditions (pH 6.4 and 6.7), Zn was leached from the brass and exceeded the threshold value (0.5 mg L(-1)) in the filter outflow by up to a factor of 40. Increasing pH (>8.5) decreased the Zn concentration (<0.05 mg L(-1)) but affected Hg removal due to the formation of Zn-hydroxide/carbonate coatings on the brass (up to 15% performance reduction). Thus, the use of brass shavings as an exclusive filter material in PRBs is restricted to aquifers with high pH. However, brass is ideal as a low-cost, thin-bed prefilter in onsite systems to remove the main Hg load from groundwater when Zn release is managed.

Mercury (II) reduction and co-precipitation of metallic mercury on hydrous ferric oxide in contaminated groundwater.

Mercury (Hg) speciation and sorption analyses in contaminated aquifers are useful for understanding transformation, retention, and mobility of Hg in groundwater. In most aquifers hydrous ferric oxides (HFOs) are among the most important sorbents for trace metals; however, their role in sorption or mobilization of Hg in aquifers has been rarely analyzed. In this study, we investigated Hg chemistry and Hg sorption to HFO under changing redox conditions in a highly HgCl2-contaminated aquifer (up to 870µgL(-1) Hg). Results from aqueous and solid phase Hg measurements were compared to modeled (PHREEQC) data. Speciation analyses of dissolved mercury indicated that Hg(II) forms were reduced to Hg(0) under anoxic conditions, and adsorbed to or co-precipitated with HFO. Solid phase Hg thermo-desorption measurements revealed that between 55 and 93% of Hg bound to HFO was elemental Hg (Hg(0)). Hg concentrations in precipitates reached more than 4 weight %, up to 7000 times higher than predicted by geochemical models that do not consider unspecific sorption to and co-precipitation of elemental Hg with HFO. The observed process of Hg(II) reduction and Hg(0) formation, and its retention and co-precipitation by HFO is thought to be crucial in HgCl2-contaminated aquifers with variable redox-conditions regarding the related decrease in Hg solubility (factor of ~10(6)), and retention of Hg in the aquifer.

Feasibility of cognitive functional assessment in cardiac arrest survivors using an abbreviated laptop-based neurocognitive battery.

Cardiac arrest survivors exhibit varying degrees of neurological recovery even in the setting of targeted temperature management (TTM) use, ranging from severe impairments to making a seemingly full return to neurologic baseline function. We sought to explore the feasibility of utilizing a laptop-based neurocognitive battery to identify more subtle cognitive deficits in this population. In a convenience sample of cardiac arrest survivors discharged with a cerebral performance category (CPC) of 1, we evaluated the use of a computerized neurocognitive battery (CNB) in this group compared to a healthy control normative population. The CNB was designed to test 11 specific neurocognitive domains, including such areas as working memory and spatial processing. Testing was scored for both accuracy and speed. In a feasibility convenience sample of 29 cardiac arrest survivors, the mean age was 52.9±16.7 years; 12 patients received postarrest TTM and 17 did not receive TTM. Patients tolerated the battery well and performed at normative levels for both accuracy and speed on most of the 11 domains, but showed reduced accuracy of working memory and speed of spatial memory with large magnitudes (>1 SD), even among those receiving TTM. Across all domains, including those using speed and accuracy, 7 of the 29 subjects (24%) achieved statistically significant scores lower from the normative population in two or more domains. In this population of CPC 1 cardiac arrest survivors, a sensitive neurocognitive battery was feasible and suggests that specific cognitive deficits can be detected compared to a normative population, despite CPC 1 designation. Such testing might allow improved measurement of outcomes following TTM interventions in future trials.

Facial emotion perception differs in young persons at genetic and clinical high-risk for psychosis.

A large body of literature has documented facial emotion perception impairments in schizophrenia. More recently, emotion perception has been investigated in persons at genetic and clinical high-risk for psychosis. This study compared emotion perception abilities in groups of young persons with schizophrenia, clinical high-risk, genetic risk and healthy controls. Groups, ages 13-25, included 24 persons at clinical high-risk, 52 first-degree relatives at genetic risk, 91 persons with schizophrenia and 90 low risk persons who completed computerized testing of emotion recognition and differentiation. Groups differed by overall emotion recognition abilities and recognition of happy, sad, anger and fear expressions. Pairwise comparisons revealed comparable impairments in recognition of happy, angry, and fearful expressions for persons at clinical high-risk and schizophrenia, while genetic risk participants were less impaired, showing reduced recognition of fearful expressions. Groups also differed for differentiation of happy and sad expressions, but differences were mainly between schizophrenia and control groups. Emotion perception impairments are observable in young persons at-risk for psychosis. Preliminary results with clinical high-risk participants, when considered along findings in genetic risk relatives, suggest social cognition abilities to reflect pathophysiological processes involved in risk of schizophrenia.

Neurocognitive performance stability in a multiplex multigenerational study of schizophrenia.

Certain cognitive measures are heritable and differentiate individuals at risk for schizophrenia from unaffected family members and healthy comparison subjects. These deficits in neurocognitive performance in patients with schizophrenia appear stable in the short-term. However, the duration of most, but not all, longitudinal studies is modest and the majority have relied on traditional average performance measures to examine stability. Using a computerized neurocognitive battery (CNB), we assessed mean performance (accuracy and speed) and intra-individual variability (IIV) in a longitudinal study aimed to examine neurocognitive stability in European-American multiplex families with schizophrenia. Thirty-four patients with schizophrenia, 65 unaffected relatives, and 45 healthy comparison subjects completed the same computerized neurocognitive assessment over approximately 5 years. Measures of mean performance showed that patients had stable accuracy performance but were slower in many neurocognitive domains over time as compared with unaffected family members and healthy subjects. Furthermore, patients and family members showed dissociable patterns of change in IIV for speed across cognitive domains: compared with controls, patients showed higher across-task IIV in performance compared with family members, who showed lower across-task IIV. Patients showed an increase in IIV over time, whereas family members showed a decrease. These findings suggest that measures of mean performance and IIV of speed during a CNB may provide useful information about the genetic susceptibility in schizophrenia.

Principal components of heritability from neurocognitive domains differ between families with schizophrenia and control subjects.

OBJECTIVE: Various measures of neurocognitive function show mean differences among individuals with schizophrenia (SZ), their relatives, and population controls. We use eigenvector transformations that maximize heritability of multiple neurocognitive measures, namely principal components of heritability (PCH), and evaluate how they distribute in SZ families and controls. METHODS: African-Americans with SZ or schizoaffective disorder (SZA) (n = 514), their relatives (n = 1092), and adult controls (n = 300) completed diagnostic interviews and computerized neurocognitive tests. PCH were estimated from 9 neurocognitive domains. Three PCH, PCH1-PCH3, were modeled to determine if status (SZ, relative, and control), other psychiatric covariates, and education were significant predictors of mean values. A small-scale linkage analysis was also conducted in a subset of the sample. RESULTS: PCH1, PCH2, and PCH3 account for 72% of the genetic variance. PCH1 represents 8 of 9 neurocognitive domains, is most highly correlated with spatial processing and emotion recognition, and has unadjusted heritability of 68%. The means for PCH1 differ significantly among SZ, their relatives, and controls. PCH2, orthogonal to PCH1, is most closely correlated with working memory and has an unadjusted heritability of 45%. Mean PCH2 is different only between SZ families and controls. PCH3 apparently represents a heritable component of neurocognition similar across the 3 diagnostic groups. No significant linkage evidence to PCH1-PCH3 or individual neurocognitive measures was discovered. CONCLUSIONS: PCH1 is highly heritable and genetically correlated with SZ. It should prove useful in future genetic analyses. Mean PCH2 differentiates SZ families and controls but not SZ and unaffected family members.

More than just tapping: index finger-tapping measures procedural learning in schizophrenia.

BACKGROUND: Finger-tapping has been widely studied using behavioral and neuroimaging paradigms. Evidence supports the use of finger-tapping as an endophenotype in schizophrenia, but its relationship with motor procedural learning remains unexplored. To our knowledge, this study presents the first use of index finger-tapping to study procedural learning in individuals with schizophrenia or schizoaffective disorder (SCZ/SZA) as compared to healthy controls. METHODS: A computerized index finger-tapping test was administered to 1169 SCZ/SZA patients (62% male, 88% right-handed), and 689 healthy controls (40% male, 93% right-handed). Number of taps per trial and learning slopes across trials for the dominant and non-dominant hands were examined for motor speed and procedural learning, respectively. RESULTS: Both healthy controls and SCZ/SZA patients demonstrated procedural learning for their dominant hand but not for their non-dominant hand. In addition, patients showed a greater capacity for procedural learning even though they demonstrated more variability in procedural learning compared to healthy controls. Left-handers of both groups performed better than right-handers and had less variability in mean number of taps between non-dominant and dominant hands. Males also had less variability in mean tap count between dominant and non-dominant hands than females. As expected, patients had a lower mean number of taps than healthy controls, males outperformed females and dominant-hand trials had more mean taps than non-dominant hand trials in both groups. CONCLUSIONS: The index finger-tapping test can measure both motor speed and procedural learning, and motor procedural learning may be intact in SCZ/SZA patients.

Patterns of Tobacco Consumption among Indian Men with Schizophrenia Compared to Their Male Siblings.

OBJECTIVE: Tobacco consumption among patients with schizophrenia has been investigated extensively in western countries, but there is a dearth of studies in India, where socio-economic and cultural variables are different. This study aims to investigate the patterns of tobacco consumption among schizophrenia patients compared with their non-psychotic siblings. METHODS: Consenting, successive male outpatients diagnosed with schizophrenia (n=100, DSM-IV criteria), and their non-psychotic brothers (n=100) were compared. Following a structured diagnostic interview, detailed information about tobacco consumption (including smokeless tobacco) was obtained using the Fagerstrom Test for Nicotine Dependence for smoked tobacco, and FTND-smokeless tobacco. The University of Pennsylvania Computerized Neurocognitive battery (CNB) was administered to a sub-group of patients (n=48). RESULTS: Schizophrenia patients initiated tobacco use at a significantly earlier age than their brothers, but there was no significant difference with regard to type, quantity or frequency of tobacco use (smoke or smokeless varieties). Patients who consumed tobacco had significantly higher positive symptom scores compared with non-users (p=0.043). There were no significant differences between nicotine dependent and non-dependent patients with regard to CNB domains except attention. CONCLUSION: Patterns of tobacco consumption were similar among schizophrenia patients and their non-psychotic brothers. Tobacco use was associated with increased positive symptom scores, but there were no significant differences in cognitive measures among nicotine dependent and non-dependent patients.

Development of abbreviated nine-item forms of the Raven's standard progressive matrices test.

The Raven's standard progressive matrices (RSPM) is a 60-item test for measuring abstract reasoning, considered a nonverbal estimate of fluid intelligence, and often included in clinical assessment batteries and research on patients with cognitive deficits. The goal was to develop and apply a predictive model approach to reduce the number of items necessary to yield a score equivalent to that derived from the full scale. The approach is based on a Poisson predictive model. A parsimonious subset of items that accurately predicts the total score was sought, as was a second nonoverlapping alternate form for repeated administrations. A split sample was used for model fitting and validation, with cross-validation to verify results. Using nine RSPM items as predictors, correlations of .9836 and .9782 were achieved for the reduced forms and .9063 and .8978 for the validation data. Thus, a 9-item subset of RSPM predicts the total score for the 60-item scale with good accuracy. A comparison of psychometric properties between 9-item forms, a published 30-item form, and the 60-item set is presented. The two 9-item forms provide a 75% administration time savings compared with the 30-item form, while achieving similar item- and test-level characteristics and equal correlations to 60-item based scores.

Age group and sex differences in performance on a computerized neurocognitive battery in children age 8-21.

OBJECTIVE: Examine age group effects and sex differences by applying a comprehensive computerized battery of identical behavioral measures linked to brain systems in youths that were already genotyped. Such information is needed to incorporate behavioral data as neuropsychological "biomarkers" in large-scale genomic studies. METHOD: We developed and applied a brief computerized neurocognitive battery that provides measures of performance accuracy and response time for executive-control, episodic memory, complex cognition, social cognition, and sensorimotor speed domains. We tested a population-based sample of 3,500 genotyped youths ages 8-21 years. RESULTS: Substantial improvement with age occurred for both accuracy and speed, but the rates varied by domain. The most pronounced improvement was noted in executive control functions, specifically attention, and in motor speed, with some effect sizes exceeding 1.8 standard deviation units. The least pronounced age group effect was in memory, where only face memory showed a large effect size on improved accuracy. Sex differences had much smaller effect sizes but were evident, with females outperforming males on attention, word and face memory, reasoning speed, and all social cognition tests and males outperforming females in spatial processing and sensorimotor and motor speed. These sex differences in most domains were seen already at the youngest age groups, and age group × sex interactions indicated divergence at the oldest groups with females becoming faster but less accurate than males. CONCLUSIONS: The results indicate that cognitive performance improves substantially in this age span, with large effect sizes that differ by domain. The more pronounced improvement for executive and reasoning domains than for memory suggests that memory capacities have reached their apex before age 8. Performance was sexually modulated and most sex differences were apparent by early adolescence.

Challenges and opportunities for genomic developmental neuropsychology: examples from the Penn-Drexel collaborative battery.

Genomics has been revolutionizing medicine over the past decade by offering mechanistic insights into disease processes and engendering the age of "individualized medicine." Because of the sheer number of measures generated by gene sequencing methods, genomics requires "Big Science" where large datasets on genes are analyzed in reference to electronic medical record data. This revolution has largely bypassed the behavioral neurosciences, mainly because of the paucity of behavioral data in medical records and the labor-intensity of available neuropsychological assessment methods. We describe the development and implementation of an efficient neuroscience-based computerized battery, coupled with a computerized clinical assessment procedure. This assessment package has been applied to a genomic study of 10,000 children aged 8-21, of whom 1000 also undergo neuroimaging. Results from the first 3000 participants indicate sensitivity to neurodevelopmental trajectories. Sex differences were evident, with females outperforming males in memory and social cognition domains, while for spatial processing males were more accurate and faster, and they were faster on simple motor tasks. The study illustrates what will hopefully become a major component of the work of clinical and research neuropsychologists as invaluable participants in the dawning age of Big Science neuropsychological genomics.

Do we recognize facial expressions of emotions from persons with schizophrenia?

OBJECTIVES: Impaired facial emotion expression is central to schizophrenia. Extensive work has quantified these differences, but it remains unclear how patient expressions are perceived by their healthy peers and other non-trained individuals. This study examined how static facial expressions of posed and evoked emotions of patients and controls are recognized by naïve observers. METHODS: Facial photographs of 6 persons with stable schizophrenia and 6 matched healthy controls expressing five universal emotions (happy, sad, anger, fear, and disgust) and neutral were selected from a previous data set. Untrained raters (N=420) viewed each photo and identified the expressed emotion. Repeated measures ANOVAs were used to assess differences in accuracy and error patterns between patient and control expressions. RESULTS: Expressions from healthy individuals were more accurately identified than those from schizophrenia patients across all conditions, except for posed sadness and evoked neutral faces, in which groups did not differ, and posed fear, in which patient expressions were more accurately identified than control expressions. Analysis of incorrect responses revealed misidentifications as neutral were most common across both groups but significantly more likely among patients. CONCLUSION: Present findings demonstrate that patient expressions of emotion are poorly perceived by naïve observers and support the concept of affective flattening in schizophrenia. These results highlight the real world implications of impairments in emotion expression and may shed light on potential mechanisms of impaired social functioning in schizophrenia.

A cognitive neuroscience-based computerized battery for efficient measurement of individual differences: standardization and initial construct validation.

There is increased need for efficient computerized methods to collect reliable data on a range of cognitive domains that can be linked to specific brain systems. Such need arises in functional neuroimaging studies, where individual differences in cognitive performance are variables of interest or serve as confounds. In genetic studies of complex behavior, which require particularly large samples, such trait measures can serve as endophenotypes. Traditional neuropsychological tests, based on clinical pathological correlations, are protracted, require extensive training in administration and scoring, and leave lengthy paper trails (double-entry for analysis). We present a computerized battery that takes an average of 1h and provides measures of accuracy and speed on 9 neurocognitive domains. They are cognitive neuroscience-based in that they have been linked experimentally to specific brain systems with functional neuroimaging studies. We describe the process of translating tasks used in functional neuroimaging to tests for assessing individual differences. Data are presented on each test with samples ranging from 139 (81 female) to 536 (311 female) of carefully screened healthy individuals ranging in age from 18 to 84. Item consistency was established with acceptable to high Cronbach alpha coefficients. Inter-item correlations were moderate to high within domain and low to nil across domains, indicating construct validity. Initial criterion validity was demonstrated by sensitivity to sex differences and the effects of age, education and parental education. These results encourage the use of this battery in studies needing an efficient assessment of major neurocognitive domains such as multi-site genetic studies and clinical trials.