A Longitudinal and Multidimensional Examination of the Associations Between Temperament and Self-Restraint During Toddlerhood.

Developing self-restraint, or the inhibition of behavior in response to a prohibition, is an important process during toddlerhood. The objective of this study was to gain a better understanding of individual differences in the development of self-restraint during toddlerhood by examining stable elements and growth of temperament (i.e., attentional control, behavioral inhibition, negative emotionality), general intelligence, and self-restraint. Participants were 412 same-sex twin pairs (approximately 90% European American) from predominately middle-class households in Colorado. Data were collected at 14, 20, 24, and 36 months. Results indicated that higher behavioral inhibition, attentional control, and intelligence were independently associated with better self-restraint, whereas higher negative emotionality was an independent predictor of lower self-restraint. The associations between temperament and self-restraint generally appeared to be stable from 14 to 36 months.

The Association Between Toddlerhood Self-Control and Later Externalizing Problems.

Lower self-control is a significant correlate or predictor of a wide range of adult outcomes, and this association may be due to more general tendencies toward childhood externalizing problems. The present study examined the association between toddlerhood self-control expressed within a "don't" compliance task (at 14-36 months) and later externalizing problems (parent-reported externalizing problems from age 4 to 12 years, teacher-reported externalizing problems from age 7 to 12 years, and self-reported conduct disorder symptoms at age 17 years) in a longitudinal, genetically informative study. The slope of self-control, but not its intercept, predicted later teacher-reported, but not parent- or self-reported, externalizing problems. That is, increase in self-control during toddlerhood was associated with lower levels of later teacher-reported externalizing problems. The slope of self-control was no longer a significant predictor of teacher-reported externalizing problems after controlling for observed disregard for others, a robust predictor of externalizing problems. Thus, the hypothesis that self-control is the primary predictor of externalizing problems was not supported. Results from genetic analyses suggested that the covariance between the slope of self-control and teacher-reported externalizing problems is due to both genetic and shared environmental influences.

Testing alternative hypotheses regarding the association between behavioral inhibition and language development in toddlerhood.

Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive language abilities were collected from 816 twins at ages 14, 20, and 24 months. Growth and regression models were fit to the data to assess the longitudinal associations between behavioral inhibition and language development from 14 to 24 months. Overall, there were significant associations between behavioral inhibition and expressive language, and minimal associations with receptive language, indicating that the association is better explained by reticence to respond rather than deficient language development.

Normal variability within a collegiate athlete sample: A rationale for comprehensive baseline testing.

OBJECTIVE: Sport-related concussions continue to garner attention as research emerges about the effects of these injuries. Many have advocated for cognitive baselines; however, there is no uniform practice of neuropsychological baseline testing at the collegiate level leading to variance in administration and interpretation. Continuing clarification on best practices is essential for the field, especially considering previous research highlighting normal variability on cognitive tests in other populations, but also the need for separate normative sources for those with attention and learning problems. This study aimed to evaluate the range of normal variability in a diverse sample of collegiate athletes administered a traditional neuropsychological baseline. METHOD: Neuropsychological baseline measures were collected on 236 Division 1 University student athletes over 4 years. Frequency of scores that fell at 1, 1.5, and 2 or greater standard deviations were reviewed. Student athletes were further evaluated for likelihood of factors which could impact results (i.e. Attention-Deficit/Hyperactivity Disorder [ADHD], Specific Learning Disorder [SLD], and psychiatric distress). RESULTS: The results demonstrated high rates of variability in most test scores for the collective sample. Student athletes at risk for ADHD, SLD, and/or psychiatric distress appeared to demonstrate a higher degree of variability relative to individuals with minimal risk. CONCLUSION: Baseline evaluation data revealed the presence of normal variability in a student athlete population. Left unrecognized, this can lead to errors in clinical recommendations given the nature of concussion. Certain individuals have risk factors which may increase the range of variability, and this should be explored further in future research.

Trail-Making Test Part B: Evaluation of the Efficiency Score for Assessing Floor-Level Change in Veterans.

OBJECTIVE: The Trail Making Test - Part B (TMT-B) is a commonly used executive control measure with a known floor effect, limiting the ability to distinguish impairment among individuals unable to complete this task in the standard time limit. Our group previously proposed the TMT-B Efficiency Score (TMT-Be), which captures performance variability among examinees who fail to complete the task. The present study assesses the TMT-Be in a longitudinal clinical sample. METHOD: Data were collected via record review of veterans who underwent two clinical neuropsychological evaluations. We identified 30 veterans (mean age Visit 1:69 ± 8.7 years) who were unable to complete TMT-B during at least one evaluation (mean days between visits = 615). Two scoring systems were utilized to examine performance variability: TMT-Be and TMT-B Prorated Score (TMT-Bpr). RESULTS: TMT-Be distribution was less skewed, but more platykuric, compared to TMT-Bpr. TMT-Be and TMT-Bpr were highly correlated. Both metrics correlated with psychomotor speed and another executive task, but not confrontation naming, providing both convergent and discriminant evidence of validity. TMT-Be, but not TMT-Bpr, detected significant decline in performance longitudinally. Age and education were significant predictors of the TMT-Be, but not TMT-Bpr, difference scores. CONCLUSIONS: Both metrics captured performance variability in a clinical sample and provided sufficient variance for examining floor-level performance on the TMT-B. TMT-Be appeared to be less prone to creating outliers and more likely to detect change. The results support the utility of the TMT-Be metric in research and clinical settings.

Distinct influences of affective and cognitive factors on children's non-verbal and verbal mathematical abilities.

Individual differences in children's math performance have been associated with math anxiety, attention problems, working memory (WM), and reading skills, but the mechanisms by which these factors jointly contribute to children's math achievement are unknown. Here, we use structural equation modeling to characterize the relation between these factors and their influence on non-verbal Numerical Operations (NO) and verbal Math Reasoning (MR) in 330 children (M=8.34years). Our findings indicate that WM plays a central role in both non-verbal NO and verbal MR, whereas math anxiety and reading comprehension have unique and more pronounced influences on MR, compared to NO. Our study elucidates how affective and cognitive factors distinctly influence non-verbal and verbal mathematical problem solving.

An examination of the developmental propensity model of conduct problems.

The present study tested specific hypotheses advanced by the developmental propensity model of the etiology of conduct problems in the Colorado Longitudinal Twin Study, a prospective, longitudinal, genetically informative sample. High negative emotionality, low behavioral inhibition, low concern and high disregard for others, and low cognitive ability assessed during toddlerhood (age 14 to 36 months) were examined as predictors of conduct problems in later childhood and adolescence (age 4 to 17 years). Each hypothesized antisocial propensity dimension predicted conduct problems, but some predictions may be context specific or due to method covariance. The most robust predictors were observed disregard for others (i.e., responding to others' distress with active, negative responses such as anger and hostility), general cognitive ability, and language ability, which were associated with conduct problems reported by parents, teachers, and adolescents, and change in observed negative emotionality (i.e., frustration tolerance), which was associated with conduct problems reported by teachers and adolescents. Furthermore, associations between the most robust early predictors and later conduct problems were influenced by the shared environment rather than genes. We conclude that shared environmental influences that promote disregard for others and detract from cognitive and language development during toddlerhood also predispose individuals to conduct problems in later childhood and adolescence. The identification of those shared environmental influences common to early antisocial propensity and later conduct problems is an important future direction, and additional developmental behavior genetic studies examining the interaction between children's characteristics and socializing influences on conduct problems are needed. (PsycINFO Database Record

Lowering the Floor on Trail Making Test Part B: Psychometric Evidence for a New Scoring Metric.

The Trail Making Test Part B (TMT-B) is widely used in clinical and research settings as a measure of executive function. Standard administration allows a maximal time score (i.e., floor score) of 300 s. This practice potentially masks performance variability among cognitively impaired individuals who cannot complete the task. For example, performances that are nearly complete receive the same 300-s score as a performance of only a few moves. Such performance differences may have utility in research and clinical settings. To address this, we propose a new TMT-B efficiency metric designed to capture clinically relevant performance variability below the standard administration floor. Our metric takes into account time, correct moves, and errors of commission and omission. We demonstrate that the metric has concurrent validity, permits statistical analysis of performances that fall below the test floor, and captures clinically relevant performance variability missed by alternative methods.

Orbitofrontal cortex volume and intrinsic religiosity in non-clinical psychosis.

Research indicates that religiosity plays a complex role in mental illness. Despite this link, little work has been done to clarify the role of religiosity in persons exhibiting non-clinical psychosis (NCP, individuals experiencing fleeting psychotic-like symptoms in the absence of a formal psychotic disorder). Further, there are no NCP investigations into whether abnormalities exist in brain structures that are associated with religiosity. Understanding these relationships in NCP is important to clarify the role of religiosity and brain structural anomalies in psychosis. Twenty individuals experiencing NCP and twenty controls were assessed for intrinsic religiosity (IR; motivation/commitment to religious beliefs and/or practices) using a well-validated self-report scale. Structural magnetic resonance imaging was used to determine volumes of the orbitofrontal cortex (OFC), a critical region that has been associated with increased religiosity. Results indicate that IR is elevated in the NCP group, and that these individuals exhibit bilateral volume reduction in both the lateral and medial OFC. Sample-wide correlations are non-significant, but show notable relationships between smaller OFC regions and increased IR. Significant negative relationships were found between OFC volume and depressive and negative symptoms. Overall, results suggest that brain abnormalities associated with NCP may also confer a heightened susceptibility for religiosity.

Sleep dysfunction and thalamic abnormalities in adolescents at ultra high-risk for psychosis.

BACKGROUND: Sleep dysfunction is a pervasive, distressing characteristic of psychosis, yet little is known regarding sleep quality prior to illness onset. At present, it is unclear whether sleep dysfunction precedes the emergence of psychotic symptoms, signifying a core feature of the disorder, or if it represents a consequence of prolonged contact with aspects of schizophrenia and its treatment (e.g., medication use or neurotoxicity) or co-morbid symptoms (e.g., depressive and manic symptomatology). The current study examined sleep dysfunction in adolescents at ultra high-risk (UHR) for psychosis, relationships between sleep disturbances and psychosis symptoms, volume of an integral sleep-structure (thalamus), and associations between thalamic abnormalities and sleep impairment in UHR youth. METHOD: Thirty-three UHR youth and 33 healthy controls (HC) participated in a self-assessment of sleep functioning (Pittsburgh Sleep Quality Index; PSQI), self and parent-report clinical interviews, and structural magnetic resonance imaging (MRI). RESULTS: UHR adolescents displayed increased latency to sleep onset and greater sleep disturbances/disrupted continuity compared to HC youth, over and above concurrent mood symptoms. Among UHR youth, increased sleep dysfunction was associated with greater negative symptom severity but not positive symptoms. Compared to HC adolescents, UHR participants displayed decreased bilateral thalamus volume, which was associated with increased sleep dysfunction. CONCLUSIONS: Sleep dysfunction occurs during the pre-psychotic period, and may play a role in the etiology and pathophysiology of psychosis. In addition, the relationship of disrupted sleep to psychosis symptoms in UHR youth indicates that prevention and intervention strategies may be improved by targeting sleep stabilization in the pre-psychotic period.