Understanding the Role of Puberty in Structural and Functional Development of the Adolescent Brain

Over the past two decades, there has been a tremendous increase in our understanding of structural and functional brain development in adolescence. However, understanding the role of puberty in this process has received much less attention. This review examines this relationship by summarizing recent research studies where the role of puberty was investigated in relation to brain structure, connectivity, and task‐related functional magnetic resonance imaging (fMRI). The studies together suggest that puberty may contribute to adolescent neural reorganization and maturational advancement, and sex differences also emerge in puberty. The current body of work shows some mixed results regarding impact and exact direction of pubertal influence. We discuss several limitations of current studies and propose future directions on how to move the field forward.     

A comparison of the independent-samples t-test and the paired-samples t-test when the observations are nonnegatively correlated pairs

An account of the behavior of the independent-samples t-test when applied to homoschedastic bivariate normal data is presented, and a comparison is made with the paired-samples t-test. Since the significance level is not violated when applying the independent-samples t-test to data which consist of positively correlated pairs and since the estimate of the variance is based on a larger number of ‘degrees of freedom’, the results suggest that when the sample size is small, one should not worry much about the possible existence of weak positive correlation. One may do better, powerwise, to ignore such correlation and use the independent-samples t-test, as though the samples were independent.     

Medical decision-making around the time of death of cognitively impaired nursing home residents: a pilot study

The purpose of this article is to describe the end-of-life process in the nursing home for three groups of cognitively-impaired nursing home residents: those who died with a medical decision-making process prior to death; those who died without such a decision-making process; and those who had a status-change event and a medical decision-making process, and did not die prior to data collection. Residents had experienced a medical status-change event within the 24 hours prior to data collection, and were unable to make their own decisions due to cognitive impairment. Data on the decision-making process during the event, including the type of event, the considerations used in making the decisions, and who was involved in making these decisions were collected from the residents' charts and through interviews with their physicians or nurse practitioners. When there was no decision-making process immediately prior to death, a decision-making process was usually reported to have occurred previously, with most decisions calling either for comfort care or limitation of care. When comparing those events leading to death with other status-change events, those who died were more likely to have suffered from troubled breathing than those who remained alive. Hospitalization was used only among those who survived, whereas diagnostic tests and comfort care were used more often with those who died. Those who died had more treatments considered and chosen than did those who remained alive. For half of those who died, physicians felt that they would have preferred less treatment for themselves if they were in the place of the decedents. The results represent preliminary data concerning decision-making processes surrounding death of the cognitively-impaired in the nursing home. Additional research is needed to elucidate the trends uncovered in this study.