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 3500 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.

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 non-overlapping 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; .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 to the 30-item form, while achieving similar item- and test-level characteristics and equal correlations to 60-item based scores.

Objective Schizophrenia is associated with deficits in ability to perceive emotion based upon tone of voice. The basis for this deficit, however, remains unclear and assessment batteries remain limited. We evaluated performance in schizophrenia on a novel voice emotion recognition battery with well characterized physical features, relative to impairments in more general emotional and cognitive function. Methods We studied in a primary sample of 92 patients relative to 73 controls. Stimuli were characterized according to both intended emotion and physical features (e.g., pitch, intensity) that contributed to the emotional percept. Parallel measures of visual emotion recognition, pitch perception, general cognition, and overall outcome were obtained. More limited measures were obtained in an independent replication sample of 36 patients, 31 age-matched controls, and 188 general comparison subjects. Results Patients showed significant, large effect size deficits in voice emotion recognition (F=25.4, p<.00001, d=1.1), and were preferentially impaired in recognition of emotion based upon pitch-, but not intensity-features (group X feature interaction: F=7.79, p=.006). Emotion recognition deficits were significantly correlated with pitch perception impairments both across (r=56, p<.0001) and within (r=.47, p<.0001) group. Path analysis showed both sensory-specific and general cognitive contributions to auditory emotion recognition deficits in schizophrenia. Similar patterns of results were observed in the replication sample. Conclusions The present study demonstrates impairments in auditory emotion recognition in schizophrenia relative to acoustic features of underlying stimuli. Furthermore, it provides tools and highlights the need for greater attention to physical features of stimuli used for study of social cognition in neuropsychiatric disorders.

The effect of ingesting charcoal-broiled (CB) beef on polycyclic aromatic hydrocarbon (PAH)-DNA adduct levels in nucleated peripheral white blood cells (WBCs) was examined in four healthy, non-smoking males who consumed an average of 280 g CB beef daily for 7 days. PAH-DNA adducts were quantitated by enzyme-linked immunosorbent assay. During the week of CB beef consumption, two individuals exhibited a 3- to 6-fold increase in PAH-DNA adducts above baseline levels observed during the month prior to CB beef consumption. In contrast, PAH-DNA adduct levels in the two other subjects did not increase. Thus, dietary sources of PAH can contribute to the PAH-DNA adduct load in peripheral WBCs in some individuals.

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