Faculty Bibliography

Aripiprazole is typically regarded as a metabolically sparing agent, in contrast to other second-generation antipsychotics, which are widely known to lead to weight gain and increase the cardiometabolic risk. We report for the first time the emergence of Acanthosis nigricans, a dermatological correlate of insulin resistance, during treatment with aripiprazole in an adolescent with a family history of diabetes mellitus.

Elevated blood urea nitrogen (BUN) is associated with increased severity of illness and mortality, but its predictive value has not been studied in patients admitted to free-standing psychiatric hospitals. To determine the clinical outcome of psychiatric inpatients with elevated BUN on admission and to create a quantitative method of using BUN for predicting deteriorations requiring transfers of psychiatric inpatients to a general hospital we conducted a retrospective cohort study of 939 adults consecutively admitted to a free-standing psychiatric hospital in 2010. Transfer to a general hospital was used as a proxy marker for poor medical outcome. The score Age (years) plus BUN (mg/dL) was used in sensitivity analyses to identify patients with medical deterioration in derivation (N = 523) and validation (N = 414) samples. Fifty-two (5.5%) patients had admission azotemia (BUN >25 mg/dL). Medical deteriorations requiring emergency transfer to a general hospital occurred in 24 (46.2%; 95% confidence interval = 32.6-49.8%) of azotemic patients and 112 (12.6%; 95% confidence interval = 10.4-14.8%) of those with normal BUN (p < 0.0001). Age + BUN >/= 90 identified 51 transferred patients and had positive and negative predictive values of 39.8 and 89.5%, respectively, in the entire sample. We conclude that psychiatric inpatients with BUN >25 mg/dL or Age + BUN >/= 90 are at risk for medical deterioration. Free-standing psychiatric hospitals should develop models of care requiring frequent, scheduled medical follow-up and enhanced monitoring for this vulnerable populations.

Many techniques of functional data analysis require choosing a measure of distance between functions, with the most common choice being L2 distance. In this article we show that using a weighted L2 distance, with a judiciously chosen weight function, can improve the performance of various statistical methods for functional data, including k-medoids clustering, nonparametric classification, and permutation testing. Assuming a quadratically penalized (e.g., spline) basis representation for the functional data, we consider three nontrivial weight functions: design density weights, inverse-variance weights, and a new weight function that minimizes the coefficient of variation of the resulting squared distance by means of an efficient iterative procedure. The benefits of weighting, in particular with the proposed weight function, are demonstrated both in simulation studies and in applications to the Berkeley growth data and a functional magnetic resonance imaging data set.

The Child PTSD Symptom Scale (Foa, Johnson, Feeny, & Treadwell, ) is a self-report measure of posttraumatic stress disorder symptoms (PTSD) in children and adolescents. Despite widespread use of this measure, no study to our knowledge has examined its psychometric properties in Latino children. This study examined the factor structure, internal consistency, and convergent validity of the measure utilizing a sample of 161 Latino students (M = 11.42 years, SD = 0.70) at high risk of exposure to community violence. Confirmatory factor analyses suggested that a 3-factor model consistent with the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, ) provided the best fit to the data. Internal consistency of the total scale and subscales was high when completed in English or Spanish. All Child PTSD Symptom Scale scores were positively correlated with violence exposure. As additional evidence of convergent validity, scores evidenced stronger correlations with internalizing symptoms than with externalizing symptoms. Results supported the use of the Child PTSD Symptom Scale as a measure of PTSD severity in Latino children, but additional research is needed to determine appropriate clinical cutoffs for Latino youths exposed to chronic levels of violence. Implications for clinical practice and future research are discussed.

We propose a penalized spline approach to performing large numbers of parallel non-parametric analyses of either of two types: restricted likelihood ratio tests of a parametric regression model versus a general smooth alternative, and nonparametric regression. Compared with naively performing each analysis in turn, our techniques reduce computation time dramatically. Viewing the large collection of scatterplot smooths produced by our methods as functional data, we develop a clustering approach to summarize and visualize these results. Our approach is applicable to ultra-high-dimensional data, particularly data acquired by neuroimaging; we illustrate it with an analysis of developmental trajectories of functional connectivity at each of approximately 70000 brain locations. Supplementary materials, including an appendix and an R package, are available online.

We examined mothers' verbal responses to their crawling or walking infants' object sharing (i.e. bids). Fifty mothers and their 13-month-olds were observed for 1 hour at home. Infants bid from a stationary position or they bid after carrying the object to their mothers. Mothers responded with affirmations (e.g. 'thank you'), descriptions ('red box'), or action directives ('open it'). Infants' locomotor status and the form of their bids predicted how mothers responded. Mothers of walkers responded with action directives more often than mothers of crawlers. Notably, differences in the responses of mothers of walkers versus those of crawlers were explained by differences in bid form between the two groups of infants. Walkers were more likely to engage in moving bids than crawlers, who typically shared objects from stationary positions. When crawlers displayed moving bids, their mothers offered action directives just as often as did mothers of walkers. Findings illustrate developmental cascades, wherein Infants' locomotor status affects how infants share objects with mothers, which in turn shapes mothers' verbal responses.

How does visual experience change over development? To investigate changes in visual input over the developmental transition from crawling to walking, thirty 13-month-olds crawled or walked down a straight path wearing a head-mounted eye tracker that recorded gaze direction and head-centered field of view. Thirteen additional infants wore a motion tracker that recorded head orientation. Compared to walkers, crawlers' field of view contained less walls and more floor. Walkers directed gaze straight ahead at caregivers, whereas crawlers looked down at the floor. Crawlers obtained visual information about targets at higher elevations-caregivers and toys-by craning their heads upward and sitting up to bring the room into view. Findings indicate that visual experiences are intimately tied to infants' posture.

The stability of a system affects how it will handle a perturbation: The system may compensate for the perturbation or not. This study examined how 14-month-old infants-notoriously unstable walkers-and adults cope with a perturbation to walking. We attached a platform to one of participants' shoes, forcing them to walk with one elongated leg. At first, the platform shoe caused both age groups to slow down and limp, and caused infants to misstep and fall. But after a few trials, infants altered their gait to compensate for the platform shoe whereas adults did not; infants recovered symmetrical gait whereas adults continued to limp. Apparently, adult walking was stable enough to cope with the perturbation, but infants risked falling if they did not compensate. Compensation depends on the interplay of multiple factors: The availability of a compensatory response, the cost of compensation, and the stability of the system being perturbed.

Perceiving possibilities for action-affordances-requires sensitivity, accuracy, and consistency. In the current study, we tested children of different ages (16-month-olds to 7-year-olds) and adults to examine the development of affordance perception for reaching through openings of various sizes. Using a psychophysical procedure, we estimated individual affordance functions to characterize participants' actual ability to fit their hand through openings and individual decision functions to characterize attempts to reach. Decisions were less accurate in younger children (16-month-olds to 5-year-olds); they were more likely to attempt impossible openings and to touch openings prior to refusing, suggesting a slow developmental trend in learning to perceive affordances for fitting through openings. However, analyses of multiple outcome measures revealed that the youngest participants were equally consistent in their decision making as the oldest ones and that every age group showed sensitivity to changes in the environment by scaling their attempts to opening size.