The Colorado LEAP study: rationale and design of a study to assess the short term longitudinal effectiveness of a preschool nutrition and physical activity program

BACKGROUND

The preschool years are a critical window for obesity prevention efforts; representing a time when children establish healthy eating habits and physical activity patterns. Understanding the context in which these behaviors develop is critical to formulating a model to address childhood obesity. The Colorado LEAP Study, an intervention study designed to prevent early childhood obesity, utilizes a social ecological approach to explore individual, family and environmental factors and their relationship to child weight status over a 3 year timeframe.

METHODS

The study is located in 5 rural Colorado preschool centers and elementary schools (2 treatment and 3 control). Treatment sites receive The Food Friends nutrition (12 weeks) and physical activity (18 weeks) interventions during preschool. Observational measures assess 3 layers of the social ecological model including individual, family and organizational inputs. Children's food preferences, food intake, gross motor skills, physical activity (pedometers/accelerometers), cognitive, physical and social self-competence and height/weight are collected. Parents provide information on feeding and activity practices, child's diet, oral sensory characteristics, food neophobia, home food and activity environment, height/weight and physical activity (pedometers). School personnel complete a school environment and policy assessment. Measurements are conducted with 3 cohorts at 4 time points - baseline, post-intervention, 1- and 2-year follow-up.

DISCUSSION

The design of this study allows for longitudinal exploration of relationships among eating habits, physical activity patterns, and weight status within and across spheres of the social ecological model. These methods advance traditional study designs by allowing not only for interaction among spheres but predictively across time. Further, the recruitment strategy includes both boys and girls from ethnic minority populations in rural areas and will provide insights into obesity prevention effects on these at risk populations.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01937481.

Effectiveness of a physical activity intervention for Head Start preschoolers: a randomized intervention study

OBJECTIVES

The level of children's motor skill proficiency may be an important determinant of their physical activity behaviors. This study assessed the efficacy of an intervention on gross motor skill performance, physical activity, and weight status of preschoolers.

METHOD

The Food Friends: Get Movin' With Mighty Moves(®) program was conducted in four Head Start centers. Measurements included the Peabody Developmental Motor Scales, pedometer counts, and body mass index (BMI) z scores.

RESULTS

The intervention led to significant changes in gross motor skills in the treatment group (n = 98) compared with the control group (n = 103) and was a strong predictor of overall gross motor performance (gross motor quotient), locomotor, stability, and object manipulation skills. No intervention effect was found for physical activity levels or weight status.

CONCLUSION

The intervention dose was adequate for enhancing gross motor skill performance but not for increasing physical activity levels or reducing BMI.

Bandpass filter settings differentially affect measurement of P50 sensory gating in children and adults

OBJECTIVE

This study investigated the effect of four different bandpass filter settings on measures of the P50 component and the signal-to-noise ratios (SNR) of averaged ERPs obtained from a sensory gating paradigm employing paired-click stimuli.

METHODS

Participants were adults (n=18) 20-55years old and children (n=25) 5-10years old who were free of neurological disorders.

RESULTS

Results show that the filter settings (0.23-75Hz, 10-50Hz, 10-75Hz, and 10-200Hz) differentially affected the P50 amplitude, noise power and SNR measures of the conditioning and test clicks, and P50 T/C ratios.

CONCLUSIONS

The 10-50Hz filter setting may be optimal in studies that include only adults as these settings resulted in the smallest mean P50 T/C ratio, a reasonable standard deviation (SD) for the ratio, and the highest SNRs. The 10-200Hz filter may be the best for studying young children as this setting had the smallest mean and SD of P50 T/C ratios for these participants.

SIGNIFICANCE

In studies that include both adults and children investigators are advised to use the 10-200Hz filter setting because the smaller variability of sensory gating in the child group helps ensure better homogeneity of variance measures between the groups.

Electroencephalography in children with and without sensory processing disorders during auditory perception

OBJECTIVE

We sought to determine whether children with sensory processing disorder (SPD) differ from typically developing children on a neurophysiological measure, the P300 component of event-related potentials produced in response to brief auditory stimulation.

METHOD

We used electroencephalographic measures (i.e., N200 and P300 components) to examine auditory processing in 20 children with SPD and 71 typically developing children, ages 5-10 yr.

RESULTS

Children with SPD demonstrated significantly smaller P300 amplitudes and shorter N200 latencies than typically developing children. Brain activity correctly distinguished children with SPD from typically developing children with 77% accuracy. We also found a significant relationship between the neurophysiological measures and functional performance on sensory and motor tasks.

CONCLUSION

This study presents empirical evidence that children with SPD display unique brain processing mechanisms compared with typical children and, therefore, provide further evidence for the neural deviations associated with SPD.

Role of pulmonary infection in the development of chronic lung disease of prematurity

We studied the role of ante- and post-natal infection in the development of chronic lung disease (CLD) of prematurity. 192 newborn infants (61 term and 131 pre-term of <34 weeks gestation: 88 with respiratory distress syndrome, 35 developed CLD and eight died) were recruited. 16S ribosomal RNA (rRNA) genes were identified by PCR of DNA isolated from 840 gastric and lung fluid samples. Ureaplasma spp. were also cultured. Presence of 16S rRNA genes (OR 1.6, 95% CI 1.2-2.2) and Ureaplasma spp. (OR 3.6, 95% CI 1.7-7.7) was significantly associated with the development of CLD. This association remained if the 16S rRNA genes and Ureaplasma spp. were first identified within the first 3 days of life (OR 2.4 (95% CI 1.4-4.1) and 3.8 (95% CI 1.4-10.0), respectively) or if first identified after 3 days of age (OR 1.7 (95% CI 1.1-2.8) and OR 5.1 (95% CI 1.3-19.8), respectively). Peak lung fluid interleukin (IL)-6 and IL-8 were significantly associated with presence of microbes (p<0.0001 and p=0.0001, respectively) and development of CLD (p=0.003 and 0.001, respectively). Both early and late microbial presence in neonatal lung fluid samples was significantly associated with the development of CLD suggesting that both ante- and post-natal infection play a role in the development of CLD.

Evidence review to investigate the support for subtypes of children with difficulty processing and integrating sensory information

We investigated the evidence for subtypes in children with difficulty processing and integrating sensory information. Fifty-seven articles were incorporated into a systematic literature review; only 4 articles provided direct evidence for subtypes. These studies did not provide a comprehensive assessment of all sensory functions and sensory-based motor functions (i.e., praxis) and included different diagnostic groups. Therefore, generalized conclusions about subtypes could not be drawn. The other 53 studies reviewed provided meaningful information about strengths and challenges that children with difficulty processing and integrating sensory information demonstrate, but these studies were limited in scope. A principal theme was the importance of conducting comprehensive assessments of sensory-based functions, including multiple measures of sensory integrative functions such as praxis, sensory modulation, and sensory discrimination in children and adolescents with various clinical disorders. In addition, more consistency in the use of specific assessment tools will allow for synthesis of data across studies.

Middle and Late Latency ERP Components Discriminate between Adults, Typical Children, and Children with Sensory Processing Disorders

This study examined whether combinations of middle latency sensory evoked potential components and late components, possibly indicative of cognitive processing, can discriminate between three sample groups; 18 adults (20–55 years), 25 typical children (5–10 years) and 28 children with sensory processing disorders (SPD) (5–12 years). Electroencephalography (EEG) recordings were made while participants heard random presentations of two auditory stimuli (1 and 3 kHz) each at two intensities (50 and 70 dB). Amplitude and latency measurements were obtained for the N1, P2, N2, and P3 components from the averaged event-related potential (ERP) for each of the four auditory stimuli. Discriminant analyses revealed two functions, one which described the relationship of the components on SPD deficit continuum and one which described the relationship of these components on a developmental continuum. Together, these two functions correctly classified 90.5% of the participants as to their group membership. These results are discussed in relation to neurodevelopmental theories.

Rasch Analysis of the School Function Assessment Provides Additional Evidence for the Internal Validity of the Activity Performance Scales

OBJECTIVE. The internal construct validity of the School Function Assessment (SFA) was determined by examining its unidimensionality and hierarchical structure.

METHOD. The SFA was completed for 64 elementary school children (35 with disabilities, 29 without disabilities). Data were examined through Rasch analysis.

RESULTS. The majority of test items (252 of 266) within the Activity Performance Scales met the criterion set for Rasch goodness-of-fit statistics. All but three scales were found to be unidimensional, measuring a single construct. Item difficulty analysis yielded a hierarchical structure of the scales similar to the existing item layout of the SFA.

CONCLUSION. Internal validity was supported for 15 of the 18 Activity Performance scales. Each scale is psychometrically sound in measuring a specific functional task. The reliable hierarchical pattern of the assessment helps anticipate and document the student's progress in functional performance from easier to more difficult school tasks.

Error Monitoring in College Students with Attention-Deficit/Hyperactivity Disorder

Recent error-related event-related potential (ERP) studies suggest that children with attention-deficit/hyperactivity disorder (ADHD) display deficits in error monitoring compared to control children. Information regarding error monitoring deficit in adults with ADHD, however, is scarce. We investigated error monitoring in a sample of college students with ADHD and compared them to their control peers. In addition to error (-related) negativity (Ne/ERN) and error positivity (Pe), we examined behavioral performance such as reaction time (RT) as well as self-reported monitoring behaviors in daily-life situations. Thirty-two college students with no known disorders and 36 college students with ADHD between 18 and 30 years of age participated in this study. Results showed that college students with ADHD were slower in their RT and displayed more RT variability. College students with ADHD also demonstrated significantly smaller Ne/ERN amplitude and shorter Ne/ERN latency compared to control students. There were, however, no significant group differences in either Pe amplitude or Pe latency. With self-reported monitoring behaviors, ADHD students reported significantly more difficulties in both the Self-Monitor and Task Monitor scales of the Behavioral Rating Inventory of Executive Function – Adult Version (BRIEF-A) compared to control students. Collectively, these results suggest that college students with ADHD have atypical error monitoring as measured by brain processing, behavioral performance, and self-report.

Maturation of sensory gating performance in children with and without sensory processing disorders

Recent interest in sensory gating in children with and without neuropsychological disorders has resulted in a number of studies and the results regarding the developmental trajectory of sensory gating are inconsistent. We investigated the maturational course of sensory gating in samples of typically developing children and children with sensory processing deficits (SPD) and compared their performance to adults. Besides gating ratios, we also examined the brain responses to conditioning and test click stimuli in the sensory gating paradigm separately to clarify if the changes in click amplitudes could explain the maturational change in the T/C ratio in children. Eighteen adults with no known disorders, 25 typical children, and 28 children with SPD participated in this study. The children ranged in ages between 5 and 12 years. The three groups differed in their P50 and N100 ERP components. Both child groups displayed significantly less gating than the adults. Children with SPD demonstrated significantly less gating and more within-group variability compared to typical children. There were significant relationships between age and T/C ratios and between age and peak-to-peak amplitude of the conditioning click in typical children but not in children with SPD. Typical children demonstrated significantly smaller brain response amplitudes to the clicks as compared to adults. These findings suggest that there is a maturational course of sensory gating in typical children and if there is a maturational trajectory in children with SPD it appears to be different than typical children. In addition, children with SPD were found to be lacking in their ability to filter out repeated auditory input and failed to selectively regulate their sensitivity to sensory stimuli.

Multisensory integration in children: a preliminary ERP study

The spatio-temporal scalp distribution of multisensory auditory-somatosensory integration was investigated in typically developing children ages 6-13. Event-related potentials were recorded from 32 scalp electrodes while participants watched a silent cartoon. Three types of sensory stimulation were presented pseudo-randomly: auditory clicks, somatosensory median nerve electrical pulses, or simultaneous auditory and somatosensory stimuli. No behavioral responses were required of the participant. To examine integration, responses to simultaneous auditory and somatosensory stimulation were compared to the sum of unisensory auditory plus unisensory somatosensory responses for four time-windows: (60-80 ms, 80-110 ms, 110-150 ms and 180-220 ms). Results indicated significant multisensory integration occurred in central/post-central scalp regions between 60-80 ms in the hemisphere contralateral to the side of somatosensory stimulation and between 110-150 ms in the hemisphere ipsilateral to the side of somatosensory stimulation. Between 180-220 ms, significant multisensory integration was evident in central/post-central regions in both hemispheres as well as midline scalp regions. This study suggests that children exhibit differential processing of multisensory compared to unisensory stimuli, as has previously been reported in adults.

Validating the diagnosis of sensory processing disorders using EEG technology

OBJECTIVE

This study tested the assumption of sensory integration theory that states that a relationship exists between brain function and the behavioral manifestations of sensory integrative dysfunction.

METHOD

Electroencephalographic measures were used to examine brain processing in 28 children with sensory processing disorders (SPD) and 25 children who were typically developing, ages 5-12 years.

RESULTS

Children with SPD demonstrated less sensory gating than children who were typically developing. A significant relationship between sensory gating and age was found in children who were typically developing but not in children with SPD. Brain activity correctly distinguished children with SPD from children who were typically developing with 86% accuracy.

CONCLUSION

These results present empirical evidence that children with SPD display unique brain processing mechanisms compared to children who are typically developing and provide external validity for the diagnosis of SPD.

Calpain Inhibition by α-Ketoamide and Cyclic Hemiacetal Inhibitors Revealed by X-ray Crystallography,

Calpains are intracellular calcium-activated cysteine proteases whose unregulated proteolysis following the loss of calcium homeostasis can lead to acute degeneration during ischemic episodes and trauma, as well as Alzheimer's disease and cataract formation. The determination of the crystal structure of the proteolytic core of mu-calpain (muI-II) in a calcium-bound active conformation has made structure-guided design of active site inhibitors feasible. We present here high-resolution crystal structures of rat muI-II complexed with two reversible calpain-specific inhibitors employing cyclic hemiacetal (SNJ-1715) and alpha-ketoamide (SNJ-1945) chemistries that reveal new details about the interactions of inhibitors with this enzyme. The SNJ-1715 complex confirms that the free aldehyde is the reactive species of the cornea-permeable cyclic hemiacetal. The alpha-ketoamide warhead of SNJ-1945 binds with the hydroxyl group of the tetrahedral adduct pointing toward the catalytic histidine rather than the oxyanion hole. The muI-II-SNJ-1945 complex shows residue Glu261 displaced from the S1' site by the inhibitor, resulting in an extended "open" conformation of the domain II gating loop and an unobstructed S1' site. This conformation offers an additional template for structure-based drug design extending to the primed subsites. An important role for the highly conserved Glu261 is proposed.

Crystal Structures of Calpain–E64 and –Leupeptin Inhibitor Complexes Reveal Mobile Loops Gating the Active Site

The endogenous calpain inhibitor, calpastatin, modulates some patho-physiological aspects of calpain signaling. Excess calpain can escape this inhibition and as well, many calpain isoforms and autolytically generated protease core fragments are not inhibited by calpastatin. There is a need, therefore, to develop specific, cell-permeable calpain inhibitors to block uncontrolled proteolysis and prevent tissue damage during brain and heart ischemia, spinal-cord injury and Alzheimer's diseases. Here, we report the first high-resolution crystal structures of rat mu-calpain protease core complexed with two traditional, low molecular mass inhibitors, leupeptin and E64. These structures show that access to a slightly deeper, but otherwise papain-like active site is gated by two flexible loops. These loops are divergent among the calpain isoforms giving a potential structural basis for substrate/inhibitor selectivity over other papain-like cysteine proteases and between members of the calpain family.

Development of response-monitoring ERPs in 7- to 25-year-olds

In a target discrimination task, trials with incorrect responses elicit event-related potentials (ERPs) that include an error-related negativity (ERN or Ne) and a later error-positivity (Pe). Substantial evidence points to the anterior cingulate cortex as the source generator of the ERN. We examined the development of ERP component morphology, amplitude and latency to processing of correct and incorrect responses in 124 children, 7 to 18 years of age, and 27 adults, 19 through 25 years of age. The ERN and Pe were recorded during a standard 480-trial visual flanker task. As expected, response times decreased significantly with age. The ERN amplitude in error trials increased with age, although this was qualified by a nonlinear change as well. The Pe amplitude did not change with age. In correct trials, most participants produced a small negativity corresponding to the timing of the ERN in error trials. This correct-response negativity (CRN) amplitude was larger in children than in adults. Results are discussed with respect to continued maturation of the anterior cingulate cortex and prefrontal cortex into young adulthood.

Charting the maturation of the frontal lobe: An electrophysiological strategy

Tracking the functional development of specific regions of the prefrontal cortex in children using event-related potentials (ERPs) is challenging for both technical and conceptual reasons. In this paper we outline our strategy for studying frontal lobe development and present preliminary results from children aged 7-17 years and young adults using ERPs functionally associated with anterior cingulate and prefrontal cortex, especially the orbitofrontal, ventral, and medial portions. Our analysis of contingent negative variation, error-related negativity, and novelty P300 data show that the ERPs associated with these regions are still maturing into late adolescence, and that their amplitude has significant correlations with behavioral capacities.

Development of Error-Monitoring Event-Related Potentials in Adolescents

In order to study the maturation of neurobehavioral systems involved in affect regulation and behavioral choices during adolescence, we examined brain activity associated with response monitoring and error detection using event-related potentials (ERPs). In a visual flanker test, trials with incorrect responses elicit ERP components including an error-related negativity (ERN) and a later error-positivity (Pe). We examined the amplitude and latency of the ERN and Pe of incorrect responses in 124 children from 7 to 18 years of age. The ERN amplitude in error trials increased with age although this was qualified by a nonlinear change. The quadratic distribution of the ERN indicated an initial drop in amplitude (lowest at age 10 for girls; age 13 for boys) with a subsequent rise through adolescence. The Pe amplitude did not change with age. Results are discussed with respect to continued maturation of the anterior cingulate cortex and possible influences on adolescent behaviors.

Occupational therapy effects on visual-motor skills in preschool children

OBJECTIVE

The purpose of this study was to evaluate the assumption that preschool children who receive occupational therapy will demonstrate significant improvement in their visual-motor skills as measured on the Developmental Test of Visual-Motor Integration (VMI) and the two supplemental Visual Perception and Motor Coordination tests.

METHOD

Preschool children with developmental delays (n = 12) received occupational therapy a minimum of one individual 30-minute session, and one group 30-minute session per week for 1 school year. Their performance was compared to that of two control groups; preschool students without disabilities who received occupational therapy (n = 16) for one 30-minute group session per week and students without disabilities (n = 15) who received no occupational therapy. The VMI and two supplemental tests were administered three times to each student, at the beginning, middle, and end of school year.

RESULTS

Planned comparison tests showed that students with developmental delays demonstrated statistically significant improvement in visual-motor skills and developed skills at a rate faster than expected when compared to typically developing peers on the VMI. The effect size for preschool students without disabilities who received occupational therapy exceeded the effect size for the VMI and Visual Perception supplemental test for the preschool students without disabilities who received no therapy, although, the difference in the post-test performance of these two groups was not statistically significant.

DISCUSSION

The results of this study demonstrate that intervention, including occupational therapy, can effectively improve visual-motor skills in preschool-aged children.

Validity and reliability of the school function assessment in elementary school students with disabilities

This study examined validity of the School Function Assessment (SFA) and interrater reliability of occupational therapist and teacher ratings of students' school function. The validity of the SFA was examined using the known-group method in 35 participants in kindergarten through 7th grade attending elementary schools; 15 students with learning disabilities (LD), 11 students with autism, and 9 students with traumatic brain injury (TBI). The SFA criterion scores for the 23 individual scales were clustered into five distinct parts for the validity analyses. Significant differences in SFA scores among the 3 groups of students were found using Kruskal-Wallis analyses (Chi2 ranged from 9.28 to 20.55, p <.01). Two discriminant analyses demonstrated high correct classification of students with autism and LD, but showed less accurate classification of students with TBI, indicating that the SFA scores of students with TBI did not fall into a systematic pattern for classification. For the interrater reliability study, 16 students' ratings by their teacher and occupational therapist were analyzed. Intraclass correlations resulted in moderate relationships between teacher and occupational therapist ratings for the average criterion scores for the three main sections of the SFA: participation,.70; task supports,.68; and activity performance,.73. Results of this study are discussed in terms of validity of score interpretation and the reliability of different team members completing the SFA questionnaire.

A second binding site revealed by C-terminal truncation of calpain small subunit, a penta-EF-hand protein

The subunits in calpain and in the related penta-EF-hand (PEF) proteins are bound through contacts between the unpaired EF-hand 5 from each subunit. To study subunit binding further, a tetra-EF-hand 18 kDa N- and C-terminally truncated form of the calpain small subunit was prepared (18k). This protein does not combine with the calpain large subunit to form active calpain, but forms homodimers in solution, as shown by ultracentrifugation. The X-ray structure of the 18k protein in the presence of cadmium was solved to a resolution of 2.0 A. The structure of the monomer is almost identical to the known structure of the calpain small subunit, but the 18k protein forms an oligomer in the crystal by the use of two binding sites. One of these sites is an artefact arising from the C-terminal truncation, but the other is a naturally occurring site that is fully exposed to water in intact purified calpain. The characteristics of this site suggest that it may be important in binding other protein modulators involved in the regulation of calpain and of PEF proteins.

Error negativity and response control

Error trials are associated with faster responses than correct trials in simple discrimination tasks suggesting that errors result from impulsive responding. We investigated the relationship between error negativity (Ne/ERN), an event-related potential associated with error detection, and two behavioral indices of response control: response time (RT) differences between incorrect and correct trials (an index of impulsivity) and percentage of errors. Response-locked ERPs were collected from 17 young adults during a visual flanker task. Consistent with previous findings, participants were significantly faster on error trials. However, participants who exhibited larger Ne/ERN peak amplitudes had significantly smaller RT differences, suggesting a more controlled response strategy. Furthermore, Ne/ERN latencies were positively associated with percentage of errors. These findings are consistent with the view that the Ne/ERN reflects the activity of a monitoring system that is closely linked to remedial systems responsible for individual differences in response control or impulsive behavior.