Tammy F. Greer

Cognitive Function in Children With Type 1 Diabetes A meta-analysis

OBJECTIVE—To quantify the magnitude and pattern of cognitive difficulties in pediatric type 1 diabetes as well as the effects associated with earlier disease onset and severe hypoglycemia. RESEARCH DESIGN AND METHODS—Pediatric studies of cognitive function since 1985 were identified for study inclusion using MEDLINE and PsycInfo. Effect size (ES, Cohens d) between the diabetic and control groups, expressed in SD units, were calculated within cognitive domains to standardize meta-analysis test performance. RESULTS—The meta-analysis sample of 2,144 children consisted of 1,393 study subjects with type 1 diabetes and 751 control subjects from 19 studies. Overall, type 1 diabetes was associated with slightly lower overall cognition (ES −0.13), with small differences compared with control subjects across a broad range of domains, excluding learning and memory, which were similar for both groups. Learning and memory skills, both verbal and visual (−0.28 and −0.25), were more affected for children with early-onset diabetes (EOD) than late-onset diabetes (LOD), along with attention/executive function skills (−0.27). Compared with nondiabetic control subjects, EOD effects were larger, up to one-half SD lower, particularly for learning and memory (−0.49). Generally, seizures were associated with a negligible overall cognition ES of −0.06, with slight and inconsistent cognitive effects found on some measures, possibly reflecting the opposing effects of poorer versus better metabolic control. CONCLUSIONS—Pediatric diabetes generally relates to mildly lower cognitive scores across most cognitive domains. Cognitive effects are most pronounced and pervasive for EOD, with moderately lower performance compared with control subjects. Seizures are generally related to nominal, inconsistent performance differences.

Skew and Internal Consistency

The effects of skew on the standardized item alpha were examined with Monte Carlo techniques. Alphas computed from normal variables were compared with alphas from lognormal variables, ranks, and skewed versus normal Likert-type variables. The extent and direction of skew were varied, as was the size of the population interitem correlation (rho), the number of items, and the number of categories for Likert-type variables. Because the average interitem correlation affects alpha and skew affects the average interitem correlation, the effect of skew on the average interitem correlation also was examined. Results indicated that skew decreased the average interitem correlation and produced small decreases in alpha that were largest when skew was large, rho was small, items were skewed in opposite directions, and there were fewer items.

A Monte Carlo Evaluation of the Tetrachoric Correlation Coefficient

The tetrachoric correlation coefficient (r tet), computed from a phi coefficient, approximates what the bivariate normal correlation would have been had the dichotomous variables been analyzed in their continuous form with underlying normal distributions. Although often used by early researchers to adjust phi when marginal distributions had extreme proportions, r tet, more commonly, has been regarded with suspicion. The purpose of these Monte Carlo simulationswas to investigate the inaccuracy of r tet. More specifically, the bias and standard error of r tet was examined for dichotomized scores computed from bivariate normal and lognormal continuous raw scores when the proportions of 0s and 1s ranged from somewhat to extremely skewed. Findings indicated that r tet tended to estimate what Pearson’s r may have been if symmetry in the marginal distributions of continuous rawscores had been induced by transformation and that in general (a) r tet exhibited little bias with standard errors slightly less than double those for Pearson’s r with proportions of 1s between .3 and .7, (b) r tet performed well with proportions more extreme than .3 and .7 provided there were no empty cells, (c) r tet resulted in less bias and smaller standard errors with larger sample sizes, and (d) the .5 adjustment further reduced bias and the standard error of r tet.

Latent variables analysis : applications for developmental research

PART ONE: THEORETICAL ISSUES: CONCEPTS IN LATENT VARIABLES ANALYSIS Causal Inference in Latent Variable Models - Michael E Sobel The Theory of Confounding and its Application in Causal Modeling with Latent Variables - Rolf Steyer and Thomas Schmitt The Specification of Equivalent Models before the Collection of Data - Scott L Hershberger PART TWO: ANALYSIS OF LATENT VARIABLES IN DEVELOPMENTAL RESEARCH: CONTINUOUS VARIABLES APPROACHES The Effect of Unmeasured Variables and their Interactions on Structural Models - Phillip K Wood Exploratory Factor Analysis with Latent Variables and the Study of Processes of Development and Change - John R Nesselroade Dynamic Latent Variable Models in Developmental Psychology - Peter C M Molenaar Latent Variables Models and Missing Data Analysis - Michael J Rovine On the Arbitrary Nature of Latent Variables - Peter C M Molenaar and Alexander von Eye PART THREE: ANALYSIS OF LATENT VARIABLES IN DEVELOPMENTAL RESEARCH: CATEGORICAL VARIABLES APPROACHES Latent Class Models for Longitudinal Assessment of Trait Acquisition - George B Macready and C Mitchell Dayton Latent Trait Models for Measuring Change - Christiane Spiel Measuring Change Using Latent Class Analysis - Anton K Formann Mixture Decomposition when the Components are of Unknown Form - Hoben Thomas Latent Variables in Log-Linear Models of Repeated Observations - Jacques A Hagenaars Latent Logit Models with Polytomous Effects Variables - Allan L McCutcheon Latent Variables Markov Models - Rolf Langeheine PART FOUR: TESTING IN THE ANALYSIS OF LATENT VARIABLES Corrections to Test Statistics and Standard Errors in Covariance Structure Analysis - Albert Satorra and Peter M Bentler Testing in Latent Class Models Using a Posterior Predictive Check Distribution - Donald B Rubin and Hal S Stern

Diverse Research on Alcohol and Aggression in Humans: In Memory of John A. Carpenter

This article summarizes the proceedings of a symposium, chaired and co-organized by Helene Raskin White and co-organized by Peter R. Giancola, that was presented at the 2002 RSA Meeting in San Francisco. The goal of this symposium was to integrate findings from methodologically divergent studies on the topic of alcohol-related aggression in humans. The investigators focused on isolating mediators and moderators of the alcohol-aggression relationship. Peter R. Giancola presented laboratory data demonstrating how alcohols acute effects on aggression are moderated by individual difference and contextual factors. Mitchell E. Berman presented laboratory data on alcohols acute effects on self-induced aggression. Helene Raskin White reviewed prospective data on how alcohol affects the intergenerational transmission of family violence. Stephen Chermack reviewed data on the impact of a family history of alcoholism and a family history of violence on the development of childhood behavioral problems and adult problems with drugs, alcohol, and violence. Finally, Kenneth E. Leonard presented data on personal and contextual factors influencing alcohol-related barroom violence.

Handedness and Lateralised Tympanic Membrane Temperature in Relation to Approach-Avoidance Behaviour in Garnett's Bushbaby (Otolemur garnettii)

Studies of handedness suggest a relationship between hemispheric specialisation and emotional processing. Recently measures of lateralised tympanic membrane temperature (TMT) have identified similar relationships (i.e., the left hemisphere is involved in approach behaviour and the right hemisphere avoidance behaviour). In the present study we examined lateralised changes in TMT in response to social interaction in 10 Garnetts bushbabies. Additionally, we examined whether handedness could be used as a predictor of approach–avoidance tendencies. We found a positive association between temperature change and both allogrooming and affiliative approach. Social behaviour did not differ between right- and left-handed bushbabies. These findings are discussed in terms of existing theories of asymmetric emotional processing. Overall, the data suggest that there is a left hemisphere specialisation for processing approach-related behaviours, which is consistent with existing models of lateralised emotional processing. Our data also indicate that TMT is a reliable, cost-effective measure of cerebral activation that is less invasive and more practical than alternative measures such as EEG, PET, and fMRI.

A computer-assisted administration of the Continuous Visual Memory Test.

The Continuous Visual Memory Test (CVMT) is a continuous design recognition test designed for the assessment of visual memory for clinical and research applications. Comparisons were made between the traditional and a computer-assisted format of the CVMT using 51 university students. Formats were compared on five CVMT dependent measures, concurrent validity, split-half reliability, and selected dependent measures from the California Verbal Learning Test (CVLT). Participants scored higher on the computer format dependent measures, with the exception of false alarms (new items incorrectly identified as old), which remained comparable between formats. Adequate concurrent validity (r = .70) and split-half reliability (rs = .61–.70) were demonstrated for CVMT Total Score. Restriction of range and ceiling effects precluded reliability and validity conclusions for CVMT Delay. The computer format showed a nonsignificant trend towards lower correlations with CVLT dependent measures.

Canonical Correlation and Chi-Square: Relationships and Interpretation

Abstract A 2 × 2 chi-square can be computed from a phi coefficient, which is the Pearson correlation between two binomial variables. Similarly, chi-square for larger contingency tables can be computed from canonical correlation coefficients. The authors address the following series of issues involving this relationship: (a) how to represent a contingency table in terms of a correlation matrix involving r - 1 row and c - 1 column dummy predictors; (b) how to compute chi-square from canonical correlations solved from this matrix; (c) how to compute loadings for the omitted row and column variables; and (d) the possible interpretive advantage of describing canonical relationships that comprise chi-square, together with some examples. The proposed procedures integrate chi-square analysis of contingency tables with general correlational theory and serve as an introduction to some recent methods of analysis more widely known by sociologists.

Age-related decline in lateralised prey capture success in Garnett's bushbaby (Otolemur garnettii)

We examined differences in prey capture success when reaching for moving prey with the preferred and non-preferred hand (as determined previously using stationary food items) in 12 Garnetts bushbabies (Otolemur garnettii). Hand preference was determined by a test of simple reaching for stationary food items. We assessed both the frequency of hand use and success rates for each hand in capturing live mealworms. We also examined the effect of age on overall prey capture success. Subjects were individually presented with live mealworms in a cup partially filled with a cornmeal medium. The preferred hand was used significantly more often than the non-preferred hand to obtain the moving prey; however, no differences were found in the frequency of usage of the left vs the right hand. Furthermore, there were no differences in the success rates of the left vs the right hand, nor the preferred vs the non-preferred hand. There was a significant negative correlation between age and prey capture success. These data suggest that age, rather than preferred hand, may be the most relevant factor in the bushbabies’ prey capture success.