Characterizing the ADHD phenotype for genetic studies

The genetic study of ADHD has made considerable progress. Further developments in the field will be reliant in part on identifying the most appropriate phenotypes for genetic analysis. The use of both categorical and dimensional measures of symptoms related to ADHD has been productive. The use of multiple reporters is a valuable feature of the characterization of psychopathology in children. It is argued that the use of aggregated measures to characterize the ADHD phenotype, particularly to establish its pervasiveness, is desirable. The recognition of the multiple comorbidities of ADHD can help to isolate more specific genetic influences. In relation to both reading disability and conduct disorder there is evidence that genes may be involved in the comorbid condition that are different from pure ADHD. To date, progress with the investigation of endophenotypes for ADHD has been disappointing. It is suggested that extending such studies beyond cognitive underpinnings to include physiological and metabolic markers might facilitate progress.     

Managers' variance investigation decisions: an experimental examination of probabilistic and outcome ambiguity

Information ambiguity is prevalent in organizations and may influence management decisions. This study examines, given imprecise probabilities or outcomes, how managers decide which department's performance to investigate further when they are provided with performance benchmarks expressed in numerical intervals. Seventy‐nine MBA students participated in two experiments involving investigation decisions. We presented participants with interval benchmarks of a firm's expenses. Being below or above the benchmark should have been seen as equally negative. We found that, when facing outcome ambiguity, our participants consistently preferred to investigate further those departments whose performance was described as having an ambiguous outcome (when the outcome's range was centered either below or above the interval benchmark). However, when facing probabilistic ambiguity, there were two predominant choice patterns: consistently choosing to investigate the department whose performance is described with an ambiguous probability, or consistently choosing to investigate the department with unambiguous performance. To gain further insight, we conducted a follow‐up study collecting written protocols of participants' reasons for making choices involving ambiguous performance information. The results show that our participants displayed similar decision‐making processes when facing outcome ambiguity and probabilistic ambiguity. Copyright © 2001 John Wiley & Sons, Ltd.     

Pain language of bone marrow transplantation patients.

Previous studies have shown that hypnosis may be effective in reducing intensity of pain among bone marrow transplantation patients whereas cognitive behavioral intervention without imagery was not effective for this group of patients. Since hypnosis alters patients' perception of pain and cognitive behavioral intervention changes patients' beliefs and improves their coping with pain, we hypothesized that sensory pain is more important than affective pain in understanding the pain experience of patients undergoing bone marrow transplantation. To test this hypothesis we administered the McGill Pain Questionnaire longitudinally to 50 consecutive eligible recipients of bone marrow transplantation during hospitalization to assess the different dimensions of pain they experienced. Consistent with our hypothesis, sensory pain fluctuated with treatment stages, and the pattern was consistent with previous findings. Patients reported significantly higher sensory pain than affective pain at all assessment points. In contrast, affective pain remained low and stable throughout the treatment. Our results contribute to the understanding of the nature of pain in bone marrow transplantation and suggest pain management strategies that focus on sensory pain as in hypnosis are more useful for such patients.     

Effect of prefrontal cortex damage on resolving lexical ambiguity in text

The function of suppression of context-inappropriate meanings during lexical ambiguity resolution was examined in 25 adults with prefrontal cortex damage (PFCD) localized to the left (N=8), right (N=6), or bilaterally (N=11); and 21 matched Controls. Results revealed unexpected inverse patterns of suppression between PFCD and Control groups, with measures suggesting decreased interference across time in the PFCD group and increased interference in the Control group. The PFCD group, however, had significantly lower accuracy rates for the context-inappropriate condition. Results suggest a loss of the control aspects of inhibitory processes in lexical ambiguity resolution following PFCD. An aging effect on suppression function is also suggested.     

Stability of nonlinear principal components analysis: an empirical study using the balanced bootstrap

Principal components analysis (PCA) is used to explore the structure of data sets containing linearly related numeric variables. Alternatively, nonlinear PCA can handle possibly nonlinearly related numeric as well as nonnumeric variables. For linear PCA, the stability of its solution can be established under the assumption of multivariate normality. For nonlinear PCA, however, standard options for establishing stability are not provided. The authors use the nonparametric bootstrap procedure to assess the stability of nonlinear PCA results, applied to empirical data. They use confidence intervals for the variable transformations and confidence ellipses for the eigenvalues, the component loadings, and the person scores. They discuss the balanced version of the bootstrap, bias estimation, and Procrustes rotation. To provide a benchmark, the same bootstrap procedure is applied to linear PCA on the same data. On the basis of the results, the authors advise using at least 1,000 bootstrap samples, using Procrustes rotation on the bootstrap results, examining the bootstrap distributions along with the confidence regions, and merging categories with small marginal frequencies to reduce the variance of the bootstrap results.     

Effects of Parent’s Gender, Child’s Gender, and Parental Involvement on the Academic Achievement of Adolescents in Single Parent Families

We used a national database (Educational Longitudinal Study) to investigate the effects of parent’s gender, child’s gender, and parental involvement in school on the academic achievement of adolescents in single-parent families. A three way 2 × 2 × 2 (parent’s gender × child’s gender × parental involvement) MANCOVA was conducted with four student academic achievement indicators as dependent variables and SES as a covariate. The results indicated that parent gender and child gender interact with parent involvement to affect adolescents’ academic achievement differentially. Specifically, daughters who lived with highly involved single-fathers performed better academically than the other groups did. These findings suggest that researchers who study single-parents’ involvement in their adolescents’ academic achievement need to pay more attention to gender-specific effects.