Functional Brain Hyperactivations Are Linked to an Electrophysiological Measure of Slow Interhemispheric Transfer Time after Pediatric Moderate/Severe Traumatic Brain Injury.

Increased task-related blood oxygen level dependent (BOLD) activation is commonly observed in functional magnetic resonance imaging (fMRI) studies of moderate/severe traumatic brain injury (msTBI), but the functional relevance of these hyperactivations and how they are linked to more direct measures of neuronal function remain largely unknown. Here, we investigated how working memory load (WML)-dependent BOLD activation was related to an electrophysiological measure of interhemispheric transfer time (IHTT) in a sample of 18 msTBI patients and 26 demographically matched controls from the UCLA RAPBI (Recovery after Pediatric Brain Injury) study. In the context of highly similar fMRI task performance, a subgroup of TBI patients with slow IHTT had greater BOLD activation with higher WML than both healthy control children and a subgroup of msTBI patients with normal IHTT.

Callosal Function in Pediatric Traumatic Brain Injury Linked to Disrupted White Matter Integrity.

Unlabelled: Traumatic brain injury (TBI) often results in traumatic axonal injury and white matter (WM) damage, particularly to the corpus callosum (CC). Damage to the CC can lead to impaired performance on neurocognitive tasks, but there is a high degree of heterogeneity in impairment following TBI. Here we examined the relation between CC microstructure and function in pediatric TBI.

Executive function changes before memory in preclinical Alzheimer's pathology: a prospective, cross-sectional, case control study.

Background: Early treatment of Alzheimer's disease may reduce its devastating effects. By focusing research on asymptomatic individuals with Alzheimer's disease pathology (the preclinical stage), earlier indicators of disease may be discovered. Decreasing cerebrospinal fluid beta-amyloid42 is the first indicator of preclinical disorder, but it is not known which pathology causes the first clinical effects.

Metabolic levels in the corpus callosum and their structural and behavioral correlates after moderate to severe pediatric TBI.

Diffuse axonal injury (DAI) secondary to traumatic brain injury (TBI) contributes to long-term functional morbidity. The corpus callosum (CC) is particularly vulnerable to this type of injury. Magnetic resonance spectroscopy (MRS) was used to characterize the metabolic status of two CC regions of interest (ROIs) (anterior and posterior), and their structural (diffusion tensor imaging; DTI) and neurobehavioral (neurocognitive functioning, bimanual coordination, and interhemispheric transfer time [IHTT]) correlates.

Examination of various WMS-III logical memory scores in the assessment of response bias.

The assessment of response validity during neuropsychological evaluation is an integral part of the testing process. Research has increasingly focused on the use of "embedded" effort measures (derived from standard neuropsychological tasks) because they do not require additional administration time and are less likely to be identified as effort indicators by test takers because of their primary focus as measures of cognitive function. The current study examined the clinical utility of various WMS-III Logical Memory scores in detecting response bias, as well as the Rarely Missed Index, an embedded effort indicator derived from the WMS-III Logical Memory Delayed Recognition subtest.

The Warrington Recognition Memory Test for words as a measure of response bias: total score and response time cutoffs developed on "real world" credible and noncredible subjects.

Several studies have examined the usefulness of the Warrington Recognition Memory Test-Words as a measure to detect suspect effort, although samples have generally been small and/or comprised of simulators rather than "real world" credible and noncredible patients. The current study examined the Warrington Recognition Memory Test-Words total score and response time of "real world" noncredible patients (as determined by motive to feign, failure on > or =2 independent measures of response bias, low cognitive scores inconsistent with normal ADLs; n = 190) versus credible patients (as determined by no motive to feign, failure of < or =1 measure of response bias; n = 124) derived from an archival database of individuals from the Harbor-UCLA Medical Center, Department of Psychiatry, Outpatient Neuropsychology Service, and the private practice of the second author. Noncredible patients obtained significantly lower total scores and longer times to complete the task.

Bimanual motor coordination in agenesis of the corpus callosum.

The nature and extent of deficiencies in bimanual motor coordination in individuals with agenesis of the corpus callosum (ACC) was studied using the computerized Bimanual Coordination Test (cBCT). Compared with previous bimanual tasks, the cBCT is more specifically reliant on interhemispheric interactions of lateralized motor control, allows more precise measurement, and permits examination of performance over a wider range of bimanual challenges. The cBCT performance of 13 high-functioning individuals with complete ACC was compared to 21 age- and IQ-matched controls.

The role of proopiomelanocortin (POMC) in sequentially dependent self-injurious behavior.

Self-injuring behavior (SIB) is a life-threatening behavior exhibited by many species, including humans, and has no known cause and no agreed upon treatment. The role of the stress axis in the maintenance of this mysterious behavior was examined in subjects with life-long SIB. Over a 6-year period, 40 hr of direct observations of behavior and the environment were recorded on palmtop computers while 36 residential subjects (28 target and 8 control subjects) conducted their daily activities.

Age-associated predictors of medication adherence in HIV-positive adults: health beliefs, self-efficacy, and neurocognitive status.

Objective: Although most agree that poor adherence to antiretrovirals is a common problem, relatively few factors have been shown to consistently predict treatment failure. In this study, a theoretical framework encompassing demographic characteristics, health beliefs/attitudes, treatment self-efficacy, and neurocognitive status was examined in relationship to highly active antiretroviral therapy adherence.

Design: Prospective, cross-sectional observational design.

Drug use and medication adherence among HIV-1 infected individuals.

This longitudinal study examined the impact of drug use and abuse on medication adherence among 150 HIV-infected individuals, 102 who tested urinalysis positive for recent illicit drug use. Medication adherence was tracked over a 6-month period using an electronic monitoring device (MEMS caps). Over the 6-month study drug-positive participants demonstrated significantly worse medication adherence than did drug-negative participants (63 vs.

Bimanual coordination in alcohol-exposed children: role of the corpus callosum.

The corpus callosum (CC) is one of several brain structures affected in children prenatally exposed to alcohol. This structure plays a major role in coordinating motor activity from opposite sides of the body, and deficits in bimanual coordination have been documented in individuals with agenesis of or damage to the CC, particularly when the task is performed without visual feedback. The Bimanual Coordination Test was used to assess speed and accuracy on a task where both hands must coordinate to guide a cursor through angled pathways providing measures of interhemispheric interaction or the ability of the two hemispheres to coordinate activity via the corpus callosum.

Sequential analysis reveals a unique structure for self-injurious behavior.

Conditional probability, calculated using sequential analysis techniques in four time conditions (2, 10, 30, and 60 seconds), provided evidence that successive episodes of self-injury were sequentially dependent. This unique distribution of sequential association for self-injurious behavior (SIB) was not related to frequency or rate of occurrence. Compared with other environmental and behavioral events, the best predictor of SIB was an earlier SIB episode, consistent with a contagious distribution.

Normal development of bimanual coordination: visuomotor and interhemispheric contributions.

The corpus callosum is one of the last cortical pathways to develop, continuing to myelinate through the end of the first decade of life. However, the functional consequences of this late development are not entirely known. The importance of callosal development for bimanual motor coordination is suggested by the fact that bimanual coordination in younger children is similar to that of persons with commissurotomy or callosal agenesis.