Children and psychotropic medication: a cautionary note

This report addresses how the mental health field is organized in terms of the use of psychotropic medications with children and adolescents, and the ethical challenge this presents to marriage and family therapists.     

A new quantitative method for assessing sleepiness: The alpha attenuation test

Abstract

Sleepiness interferes with the ability of night-workers and shiftworkers to safely and effectively perform their jobs, and has been increasingly recognized as a major cause of industrial and transportation accidents. Current methods for the assessment of physiological sleepiness levels, such as the Multiple Sleep Latency Test (MSLT) have several limitations and are particularly impractical in field or occupational studies. In this study, the effectiveness of the Alpha Attenuation Test (AAT) for the quantification of sleepiness has been evaluated and compared to the MSLT during a 40-h sleep deprivation protocol. The AAT, a 12-min eye closed/open protocol, is a quantitative method based on the fact that EEG alpha (8-12 Hz) activity tends to increase with eyes open as individuals get sleepier, while it decreases with eyes closed. In this validation study, the AAT proved to be a sensitive measure of sleepiness induced by sleep deprivation, and it also correlated well with the MSLT. Relative to the MSLT, the AAT has the advantages of being objective, minimally intrusive, and more practical especially in industrial or field studies.     

Discussion of papers by Dempster and Aitkin

Statistics and Computing -     

Using process data to explain outcomes. An illustration from the Child and Adolescent Trial for Cardiovascular Health (CATCH)

The purpose of this article is to illustrate the use of process evaluation for understanding study outcomes. Data from the Child and Adolescent Trial for Cardiovascular Health (CATCH), a large school-based field trial, are used. Teacher characteristics, measures of classroom curriculum implementation, and competing influences are linked to changes in dietary knowledge, intentions, and self-efficacy of students in the intervention schools. Multiple regression analyses indicate that teacher characteristics did not predict program implementation. Teacher characteristics and program fidelity, or the number of modifications made to the classroom curriculum during implementation, had direct and independent effects on student outcomes.     

Emerging credits

Fifty years ago Edwin Hollander argued that to emerge as a credible leader, a group member must first develop credits with potential followers before followers can be led in a new direction. His idiosyncrasy credit theory of leadership emerged in the 1950s, gathered support in the 1960s, was questioned in the 1970s, stagnated since the 1980s and has now become a passing reference. We reexamine the theory and argue that it should be revived to span a gap in current thinking about leadership. We identify its key constructs, examine the mixed support, describe a revised model, suggest some testable research propositions and illustrate its application to the life of one prominent transformational leader.     

The L2 Rate of Convergence for Event History Regression with Time-dependent Covariates

Consider repeated events of multiple kinds that occur according to a right-continuous semi-Markov process whose transition rates are influenced by one or more time-dependent covariates. The logarithms of the intensities of the transitions from one state to another are modelled as members of a linear function space, which may be finite- or infinite-dimensional. Maximum likelihood estimates are used, where the maximizations are taken over suitably chosen finite-dimensional approximating spaces. It is shown that the L ₂ rates of convergence of the maximum likelihood estimates are determined by the approximation power and dimension of the approximating spaces. The theory is applied to a functional ANOVA model, where the logarithms of the intensities are approximated by functions having the form of a specified sum of a constant term, main effects (functions of one variable), and interaction terms (functions of two or more variables). It is shown that the curse of dimensionality can be ameliorated if only main effects and low-order interactions are considered in functional ANOVA models.     

An adaptive seamless phase II/III design for oncology trials with subpopulation selection using correlated survival endpoints

Although the statistical methods enabling efficient adaptive seamless designs are increasingly well established, it is important to continue to use the endpoints and specifications that best suit the therapy area and stage of development concerned when conducting such a trial. Approaches exist that allow adaptive designs to continue seamlessly either in a subpopulation of patients or in the whole population on the basis of data obtained from the first stage of a phase II/III design: our proposed design adds extra flexibility by also allowing the trial to continue in all patients but with both the subgroup and the full population as co-primary populations. Further, methodology is presented which controls the Type-I error rate at less than 2.5% when the phase II and III endpoints are different but correlated time-to-event endpoints. The operating characteristics of the design are described along with a discussion of the practical aspects in an oncology setting.