Motor network dynamic resting state fMRI connectivity of neurotypical children in regions affected by cerebral palsy.

Background: Normative childhood motor network resting-state fMRI effective connectivity is undefined, yet necessary for translatable dynamic resting-state-network-informed evaluation in pediatric cerebral palsy. Methods: Cross-spectral dynamic causal modeling of resting-state-fMRI was investigated in 50 neurotypically developing 5- to 13-year-old children. Fully connected six-node network models per hemisphere included primary motor cortex, striatum, subthalamic nucleus, globus pallidus internus, thalamus, and contralateral cerebellum. Parametric Empirical Bayes with exhaustive Bayesian model reduction and Bayesian modeling averaging informed the model; Purdue Pegboard Test scores of hand motor behavior were the covariate at the group level to determine the effective-connectivity-functional behavior relationship. Results: Although both hemispheres exhibited similar effective connectivity of motor cortico-basal ganglia-cerebellar networks, magnitudes were slightly greater on the right, except for left-sided connections of the striatum which were more numerous and of opposite polarity. Inter-nodal motor network effective connectivity remained consistent and robust across subjects. Age had a greater impact on connections to the contralateral cerebellum, bilaterally. Motor behavior, however, affected different connections in each hemisphere, exerting a more prominent effect on the left modulatory connections to the subthalamic nucleus, contralateral cerebellum, primary motor cortex, and thalamus. Discussion: This study revealed a consistent pattern of directed resting-state effective connectivity in healthy children aged 5-13 years within the motor network, encompassing cortical, subcortical, and cerebellar regions, correlated with motor skill proficiency. Both hemispheres exhibited similar effective connectivity within motor cortico-basal ganglia-cerebellar networks reflecting inter-nodal signal direction predicted by other modalities, mainly differing from task-dependent studies due to network differences at rest. Notably, age-related changes were more pronounced in connections to the contralateral cerebellum. Conversely, motor behavior distinctly impacted connections in each hemisphere, emphasizing its role in modulating left sided connections to the subthalamic nucleus, contralateral cerebellum, primary motor cortex, and thalamus. Motor network effective connectivity was correlated with motor behavior, validating its physiological significance. This study is the first to evaluate a normative effective connectivity model for the pediatric motor network using resting-state functional MRI correlating with behavior and serves as a foundation for identifying abnormal findings and optimizing targeted interventions like deep brain stimulation, potentially influencing future therapeutic approaches for children with movement disorders.

Resting-State Functional Magnetic Resonance Imaging Network Association With Mortality, Epilepsy, Cognition, and Motor Two-Year Outcomes in Suspected Severe Neonatal Acute Brain Injury.

BACKGROUND AND OBJECTIVES: In acute brain injury of neonates, resting-state functional magnetic resonance imaging (MRI) (RS) showed incremental association with consciousness, mortality, cognitive and motor development, and epilepsy, with correction for multiple comparisons, at six months postgestation in neonates with suspected acute brain injury (ABI). However, there are relatively few developmental milestones at six months to benchmark against, thus, we extended this cohort study to evaluate two-year outcomes. METHODS: In 40 consecutive neonates with ABI and RS, ordinal scores of resting-state networks; MRI, magnetic resonance spectroscopy, and electroencephalography; and up to 42-month outcomes of mortality, general and motor development, Pediatric Cerebral Performance Category Scale (PCPC), and epilepsy informed associations between tests and outcomes. RESULTS: Mean gestational age was 37.8 weeks, 68% were male, and 60% had hypoxic-ischemic encephalopathy. Three died in-hospital, four at six to 42 months, and five were lost to follow-up. Associations included basal ganglia network with PCPC (P = 0.0003), all-mortality (P = 0.005), and motor (P = 0.0004); language/frontoparietal network with developmental delay (P = 0.009), PCPC (P = 0.006), and all-mortality (P = 0.01); default mode network with developmental delay (P = 0.003), PCPC (P = 0.004), neonatal intensive care unit mortality (P = 0.01), and motor (P = 0.009); RS seizure onset zone with epilepsy (P = 0.01); and anatomic MRI with epilepsy (P = 0.01). CONCLUSION: For the first time, at any age, resting state functional MRI in ABI is associated with long-term epilepsy and RSNs predicted mortality in neonates. Severity of RSN abnormality was associated with incrementally worsened neurodevelopment including cognition, language, and motor function over two years.

Immediate and Intermediate-Term Effects of Disease Mitigation Measures on Activity Levels as Measured by Implantable Cardiac Devices.

Routine activities of daily living are known to effect overall wellbeing, cardiovascular health, and quality of life. A decrease in daily activity level is recognized as a contributing factor to increasing rates of obesity and a decline in overall health. This study sought to evaluate the effect of disease mitigation strategies on activity level by evaluating changes in recorded cardiac parameters as measured by implantable cardiac devices for a period of time prior to and following implementation of COVID-19 mitigation efforts in Arizona. A retrospective cohort study of cardiac device data from January 1, 2019-December 31, 2020 was performed. Linear mixed-effects models with restricted maximum likelihood estimation were utilized to test for the fixed effects of Year, day, and the interaction between them. A significant decrease in daily activity minutes, daytime heart rates, and heart rate variability coincident with the initiation of disease mitigation strategies was observed. An increase in nighttime heart rates also coincided with initiation of disease mitigation strategies. These effects were noted to persist through the end of the study period. Implementation of statewide disease mitigation strategies resulted in both immediate and intermediate-term effects on activity levels, day and nighttime heart rates trends, and heart rate variability in patients with implanted cardiac devices. These data may serve useful in counseling patients regarding the importance of activity, movement, and exercise to routine health and encourage a return to pre-pandemic levels of activity.

Treatable brain network biomarkers in children in coma using task and resting-state functional MRI: a case series.

The withdrawal of life-sustaining therapies is frequently considered for pediatric patients with severe acute brain injuries who are admitted to the intensive care unit. However, it is worth noting that some children with a resultant poor neurological status may ultimately survive and achieve a positive neurological outcome. Evidence suggests that adults with hidden consciousness may have a more favorable prognosis compared to those without it. Currently, no treatable network disorders have been identified in cases of severe acute brain injury, aside from seizures detectable through an electroencephalogram (EEG) and neurostimulation via amantadine. In this report, we present three cases in which multimodal brain network evaluation played a helpful role in patient care. This evaluation encompassed various assessments such as continuous video EEG, visual-evoked potentials, somatosensory-evoked potentials, auditory brainstem-evoked responses, resting-state functional MRI (rs-fMRI), and passive-based and command-based task-based fMRI. It is worth noting that the latter three evaluations are unique as they have not yet been established as part of the standard care protocol for assessing acute brain injuries in children with suppressed consciousness. The first patient underwent serial fMRIs after experiencing a coma induced by trauma. Subsequently, the patient displayed improvement following the administration of antiseizure medication to address abnormal signals. In the second case, a multimodal brain network evaluation uncovered covert consciousness, a previously undetected condition in a pediatric patient with acute brain injury. In both patients, this discovery potentially influenced decisions concerning the withdrawal of life support. Finally, the third patient serves as a comparative control case, demonstrating the absence of detectable networks. Notably, this patient underwent the first fMRI prior to experiencing brain death as a pediatric patient. Consequently, this case series illustrates the clinical feasibility of employing multimodal brain network evaluation in pediatric patients. This approach holds potential for clinical interventions and may significantly enhance prognostic capabilities beyond what can be achieved through standard testing methods alone.

Discerning Seizure-Onset v. Propagation Zone: Pre-and-Post-Operative Resting-State fMRI Directionality and Boerwinkle Neuroplasticity Index.

The goal of this study was to determine resting state fMRI (rs-fMRI) effective connectivity (RSEC) capacity, agnostic of epileptogenic events, in distinguishing seizure onset zones (SOZ) from propagation zones (pZ). Consecutive patients (2.1-18.2 years old), with epilepsy and hypothalamic hamartoma, pre-operative rs-fMRI-directed surgery, post-operative imaging, and Engel class I outcomes were collected. Cross-spectral dynamic causal modelling (DCM) was used to estimate RSEC between the ablated rs-fMRI-SOZ to its region of highest connectivity outside the HH, defined as the propagation zone (pZ). Pre-operatively, RSEC from the SOZ and PZ was expected to be positive (excitatory), and pZ to SOZ negative (inhibitory), and post-operatively to be either diminished or non-existent. Sensitivity, accuracy, positive predictive value were determined for node-to-node connections. A Parametric Empirical Bayes (PEB) group analysis on pre-operative data was performed to identify group effects and effects of Engel class outcome and age. Pre-operative RSEC strength was also evaluated for correlation with percent seizure frequency improvement, sex, and region of interest size. Of the SOZ's RSEC, only 3.6% had no connection of significance to the pZ when patient models were individually reduced. Among remaining, 96% were in expected (excitatory signal found from SOZ â†’ pZ and inhibitory signal found from pZ â†’ SOZ) versus 3.6% reversed polarities. Both pre-operative polarity signals were equivalently as expected, with one false signal direction out of 26 each (3.7% total). Sensitivity of 95%, specificity 73%, accuracy of 88%, negative predictive value 88%, and positive predictive value of 88% in identifying and differentiating the SOZ and pZ. Groupwise PEB analysis confirmed SOZ â†’ pZ EC was excitatory, and pZ â†’ SOZ EC was inhibitory. Patients with better outcomes (Engel Ia vs. Ib) showed stronger inhibitory signal (pZ â†’ SOZ). Age was negatively associated with absolute RSEC bidirectionally but had no relationship with Directionality SOZ identification performance. In an additional hierarchical PEB analysis identifying changes from pre-to-post surgery, SOZ â†’ pZ modulation became less excitatory and pZ â†’ SOZ modulation became less inhibitory. This study demonstrates the accuracy of Directionality to identify the origin of excitatory and inhibitory signal between the surgically confirmed SOZ and the region of hypothesized propagation zone in children with DRE due to a HH. Thus, this method validation study in a homogenous DRE population may have potential in narrowing the SOZ-candidates for epileptogenicity in other DRE populations and utility in other neurological disorders.

Is Resting State Functional MRI Effective Connectivity in Movement Disorders Helpful? A Focused Review Across Lifespan and Disease.

In the evolving modern era of neuromodulation for movement disorders in adults and children, much progress has been made recently characterizing the human motor network (MN) with potentially important treatment implications. Herein is a focused review of relevant resting state fMRI functional and effective connectivity of the human motor network across the lifespan in health and disease. The goal is to examine how the transition from functional connectivity to dynamic effective connectivity may be especially informative of network-targeted movement disorder therapies, with hopeful implications for children.

Association of network connectivity via resting state functional MRI with consciousness, mortality, and outcomes in neonatal acute brain injury.

BACKGROUND: An accurate and comprehensive test of integrated brain network function is needed for neonates during the acute brain injury period to inform on morbidity. This retrospective cohort study assessed whether integrated brain network function acquired by resting state functional MRI during the acute period in neonates with brain injury, is associated with acute exam, neonatal mortality, and 6-month outcomes. METHODS: Study subjects included 40 consecutive neonates with resting state functional MRI acquired within 31 days after suspected brain insult from March 2018 to July 2019 at Phoenix Children's Hospital. Acute-period exam and test results were assigned ordinal scores based on severity as documented by respective treating specialists. Analyses (Fisher exact, Wilcoxon-rank sum test, ordinal/multinomial logistic regression) examined association of resting state networks with demographics, presentation, neurological exam, electroencephalogram, anatomical MRI, magnetic resonance spectroscopy, passive task functional MRI, and outcomes of discharge condition, outpatient development, motor tone, seizure, and mortality. RESULTS: Subjects had a mean (standard deviation) gestational age of 37.8 (2.6) weeks, a majority were male (63%), with a diagnosis of hypoxic ischemic encephalopathy (68%). Findings at birth included mild distress (48%), moderately abnormal neurological exam (33%), and consciousness characterized as awake but irritable (40%). Significant associations after multiple testing corrections were detected for resting state networks: basal ganglia with outpatient developmental delay (odds ratio [OR], 14.5; 99.4% confidence interval [CI], 2.00-105; P < .001) and motor tone/weakness (OR, 9.98; 99.4% CI, 1.72-57.9; P < .001); language/frontoparietal network with discharge condition (OR, 5.13; 99.4% CI, 1.22-21.5; P = .002) and outpatient developmental delay (OR, 4.77; 99.4% CI, 1.21-18.7; P=.002); default mode network with discharge condition (OR, 3.72; 99.4% CI, 1.01-13.78; P=.006) and neurological exam (P = .002 (FE); OR, 11.8; 99.4% CI, 0.73-191; P = .01 (OLR)); and seizure onset zone with motor tone/weakness (OR, 3.31; 99.4% CI, 1.08-10.1; P=.003). Resting state networks were not detected in three neonates, who died prior to discharge. CONCLUSIONS: This study provides level 3 evidence (OCEBM Levels of Evidence Working Group) demonstrating that in neonatal acute brain injury, the degree of abnormality of resting state networks is associated with acute exam and outcomes. Total lack of brain network detection was only found in patients who did not survive.

Automated seizure onset zone locator from resting-state functional MRI in drug-resistant epilepsy.

Objective: Accurate localization of a seizure onset zone (SOZ) from independent components (IC) of resting-state functional magnetic resonance imaging (rs-fMRI) improves surgical outcomes in children with drug-resistant epilepsy (DRE). Automated IC sorting has limited success in identifying SOZ localizing ICs in adult normal rs-fMRI or uncategorized epilepsy. Children face unique challenges due to the developing brain and its associated surgical risks. This study proposes a novel SOZ localization algorithm (EPIK) for children with DRE. Methods: EPIK is developed in a phased approach, where fMRI noise-related biomarkers are used through high-fidelity image processing techniques to eliminate noise ICs. Then, the SOZ markers are used through a maximum likelihood-based classifier to determine SOZ localizing ICs. The performance of EPIK was evaluated on a unique pediatric DRE dataset (n = 52). A total of 24 children underwent surgical resection or ablation of an rs-fMRI identified SOZ, concurrently evaluated with an EEG and anatomical MRI. Two state-of-art techniques were used for comparison: (a) least squares support-vector machine and (b) convolutional neural networks. The performance was benchmarked against expert IC sorting and Engel outcomes for surgical SOZ resection or ablation. The analysis was stratified across age and sex. Results: EPIK outperformed state-of-art techniques for SOZ localizing IC identification with a mean accuracy of 84.7% (4% higher), a precision of 74.1% (22% higher), a specificity of 81.9% (3.2% higher), and a sensitivity of 88.6% (16.5% higher). EPIK showed consistent performance across age and sex with the best performance in those < 5 years of age. It helped achieve a ~5-fold reduction in the number of ICs to be potentially analyzed during pre-surgical screening. Significance: Automated SOZ localization from rs-fMRI, validated against surgical outcomes, indicates the potential for clinical feasibility. It eliminates the need for expert sorting, outperforms prior automated methods, and is consistent across age and sex.

Resting State Functional Magnetic Resonance Imaging Elucidates Neurotransmitter Deficiency in Autism Spectrum Disorder.

Resting-state functional magnetic resonance imaging provides dynamic insight into the functional organization of the brains' intrinsic activity at rest. The emergence of resting-state functional magnetic resonance imaging in both the clinical and research settings may be attributed to recent advancements in statistical techniques, non-invasiveness and enhanced spatiotemporal resolution compared to other neuroimaging modalities, and the capability to identify and characterize deep brain structures and networks. In this report we describe a 16-year-old female patient with autism spectrum disorder who underwent resting-state functional magnetic resonance imaging due to late regression. Imaging revealed deactivated networks in deep brain structures involved in monoamine synthesis. Monoamine neurotransmitter deficits were confirmed by cerebrospinal fluid analysis. This case suggests that resting-state functional magnetic resonance imaging may have clinical utility as a non-invasive biomarker of central nervous system neurochemical alterations by measuring the function of neurotransmitter-driven networks. Use of this technology can accelerate and increase the accuracy of selecting appropriate therapeutic agents for patients with neurological and neurodevelopmental disorders.

Early vasopressor administration in pediatric blunt liver and spleen injury: An ATOMAC+ study.

BACKGROUND: No prior studies have examined the outcomes of early vasopressor use in children sustaining blunt liver or spleen injury (BLSI). METHODS: A planned secondary analysis of vasopressor use from a 10-center, prospective study of 1004 children with BLSI. Inverse probability of treatment weighting (IPTW) was used to compare patients given vasopressors <48 h after injury to controls based on pretreatment factors. A logistic regression was utilized to assess survival associated with vasopressor initiation factors on mortality and nonoperative management (NOM) failure. RESULTS: Of 1004 patients with BLSI, 128 patients were hypotensive in the Pediatric Trauma Center Emergency Department (ED); 65 total patients received vasopressors. Hypotension treated with vasopressors was associated with a sevenfold increase in mortality (AOR = 7.6 [p < 0.01]). When excluding patients first given vasopressors for cardiac arrest, the risk of mortality increased to 11-fold (AOR = 11.4 [p = 0.01]). All deaths in patients receiving vasopressors occurred when started within the first 12 h after injury. Vasopressor administration at any time was not associated with NOM failure. CONCLUSION: After propensity matching, early vasopressor use for hypotension in the ED was associated with an increased risk of death, but did not increase the risk of failure of NOM. LEVEL OF EVIDENCE: Level III prognostic and epidemiological, prospective.

Resting-state functional MRI connectivity impact on epilepsy surgery plan and surgical candidacy: prospective clinical work.

OBJECTIVE: The authors' goal was to prospectively quantify the impact of resting-state functional MRI (rs-fMRI) on pediatric epilepsy surgery planning. METHODS: Fifty-one consecutive patients (3 months to 20 years old) with intractable epilepsy underwent rs-fMRI for presurgical evaluation. The team reviewed the following available diagnostic data: video-electroencephalography (n = 51), structural MRI (n = 51), FDG-PET (n = 42), magnetoencephalography (n = 5), and neuropsychological testing (n = 51) results to formulate an initial surgery plan blinded to the rs-fMRI findings. Subsequent to this discussion, the connectivity results were revealed and final recommendations were established. Changes between pre- and post-rs-fMRI treatment plans were determined, and changes in surgery recommendation were compared using McNemar's test. RESULTS: Resting-state fMRI was successfully performed in 50 (98%) of 51 cases and changed the seizure onset zone localization in 44 (88%) of 50 patients. The connectivity results prompted 6 additional studies, eliminated the ordering of 11 further diagnostic studies, and changed the intracranial monitoring plan in 10 cases. The connectivity results significantly altered surgery planning with the addition of 13 surgeries, but it did not eliminate planned surgeries (p = 0.003). Among the 38 epilepsy surgeries performed, the final surgical approach changed due to rs-fMRI findings in 22 cases (58%), including 8 (28%) of 29 in which extraoperative direct electrical stimulation mapping was averted. CONCLUSIONS: This study demonstrates the impact of rs-fMRI connectivity results on the decision-making for pediatric epilepsy surgery by providing new information about the location of eloquent cortex and the seizure onset zone. Additionally, connectivity results may increase the proportion of patients considered eligible for surgery while optimizing the need for further testing.

Comparison of Prehospital Calculated Age-Adjusted Pediatric Shock Index (SIPA) to Those Calculated in the ED for Identifying Trauma Patients That Needed the Highest-Level Activation Based on Consensus Criteria.

Background: The shock index (SI) is defined as the ratio of the heart rate to systolic blood pressure and a pediatric age-adjusted SI (SIPA) is more specific than the standard adult cutoff of 0.9 in identifying the sickest children presenting to a trauma center.Goal: To utilize prehospital vital signs to calculate the SIPA score and compare them to the SIPA calculated in the trauma bay to determine if they have the same validity in identifying critically ill children as determined by the consensus based standard criteria for trauma activation.Methods: Retrospective study using a cohort of patients transferred by EMS to a free standing, urban, level one, pediatric trauma center aged 1 to 16 years inclusive, and seen between January 1, 2016 and December 31, 2017. Vital signs collected during the patch call from the EMS agency were used to calculate the EMS SIPA. The first set of vital signs collected in the trauma bay was used to calculate the ED SIPA. Patients were dichotomized to an elevated or non-elevated ED SIPA and an elevated or non-elevated EMS SIPA.Results: Our cohort consisted of 2651 patients. 546 (20.6%) patients had an elevated EMS SIPA and 438 (16.5%) had an elevated ED SIPA. When compared to their non-elevated counterparts, EMS and ED SIPA were both able to identify patients who met consensus criteria in all areas except the need for IR intervention, and unstable spinal fracture/spinal cord injury. For these criteria, the ED SIPA was better than the EMS SIPA. Sensitivity and specificity analysis reveal poor sensitivity for both measures but a high specificity for ED and EMS SIPA. Both SI and SIPA have a poor PPV but high NPV.Conclusions: This study utilized prehospital vital signs to calculate the SIPA score and compare them to the SIPA calculated in the trauma bay. Both scores had similar test metrics when based on the consensus based standard trauma criteria and could be utilized in the triage traumatic injuries.

Predictive value of the shock index (SI) compared to the age-adjusted pediatric shock index (SIPA) for identifying children that needed the highest-level trauma activation based on the presence of consensus criteria.

OBJECTIVES: In previous studies, SIPA was shown to be better than the SI in identifying children who have an elevated ISS, required transfusion, or were at a high risk of death. No comparison has been made to the consensus-based criteria that identify patients requiring the highest-level trauma activation. The objective of this study was to determine if the SIPA was more accurate than the SI in identifying children with increased need for trauma team activation as defined by the criterion standard definition, and secondly the sensitivity and specificity of the SI and SIPA. METHODS: Retrospective review of prospectively collected trauma based data. Children aged 1-17 years admitted to a pediatric level 1 trauma center between 1/1/16 and 12/31/17 and met the prehospital criteria for level 1 or 2 trauma activation were included. We evaluated the ability of SI > 0.9 at ED presentation and elevated SIPA to predict need for trauma activation based on consensus criteria. SIPA cutoffs were > 1.22 (age 4-6), >1.0 (age 7-12), and > 0.9 (age 13-17). RESULTS: Among 3378 children, 1486 (44%) had an elevated SI and 590 (18%) had an elevated SIPA. There were 160 (5%) patients who met at least one consensus criterion. Broadly, sensitivity and specificity analyses reveal poor sensitivity for both SI and SIPA (59.4% versus 43.1% respectively) measures but a moderate specificity for SIPA (83.8%). Both SI and SIPA have a poor PPV (6.4% versus 11.7%) but high NPV (96.6% versus 96.7%). Overall, SIPA has higher accuracy than SI in predicting consensus criteria 82% versus 57%). CONCLUSION: SIPA is more accurate than the SI in identifying children who meet a consensus criterion defining the need for highest-level trauma activation. The low PPV and sensitivity suggest that SIPA alone, while somewhat less likely to lead to overtriage than SI is not ideal for ruling in the need for level one resources as defined by the consensus criteria. Prognosis study, retrospective. LEVEL OF EVIDENCE: Level II.

L1 Reading Experience Influences L2 Lexical Learning: Spanish Learning in Chinese Speakers and English Speakers.

L2 processing is shaped by L1 experience; however, it is not completely understood whether L1 reading experience also influences how the brain learns L2 under different learning conditions. In this study, we compare brain mechanisms of Spanish word learning in Chinese and English speakers using two learning conditions: speech-based learning and handwriting-based learning. The behavioral data suggest an advantage for learning that uses handwriting over speech-based learning across all participants. Furthermore, brain imaging data reveal that English speakers show greater functional connectivity among phonological regions in the handwriting condition than the speech-based condition during a silent phonological recall task. This suggests that, for English speakers specifically, handwriting further enhanced the phonological network. Interestingly, Chinese speakers showed an opposite pattern, with greater functional connectivity among phonological regions in the speech-based condition than the handwriting condition. Moreover, it was found that Chinese speakers with higher reading skills in their native L1 tended to engage the right fusiform to a greater degree by connecting to phonological regions in the handwriting condition. Thus, the handwriting-based learning engaged visuo-orthographic regions to a greater degree in highly skilled Chinese speakers. In summary, the current findings suggest that handwriting facilitates lexical learning by enhancing orthographic involvement in Chinese speakers, while the handwriting condition enhanced phonological involvement in English speakers. This difference between Chinese and English speakers might be due to different L1 learning experience.

Reimaging in pediatric blunt spleen and liver injury.

BACKGROUND: APSA guidelines do not recommend routine reimaging for pediatric blunt liver or spleen injury (BLSI). This study characterizes the symptoms, reimaging, and outcomes associated with a selective reimaging strategy for pediatric BLSI patients. METHODS: A planned secondary analysis of reimaging in a 3-year multi-site prospective study of BLSI patients was completed. Inclusion required successful nonoperative management of CT confirmed BLSI without pancreas or kidney injury and follow up at 14 or 60 days. Patients with re-injury after discharge were excluded. RESULTS: Of 1007 patients with BLSI, 534 (55%) met inclusion criteria (median age: 10.18 [IQR: 6, 14]; 62% male). Abdominal reimaging was performed on 27/534 (6%) patients; 3 of 27 studies prompting hospitalization and/or intervention. Abdominal pain was associated with reimaging, but decreased appetite predicted imaging findings associated with readmission and intervention. CONCLUSION: Selective abdominal reimaging for BLSI was done in 6% of patients, and 11% of studies identified radiologic findings associated with intervention or re-hospitalization. A selective reimaging strategy appears safe, and even reimaging symptomatic patients rarely results in intervention. Reimaging after 14 days did not prompt intervention in any of the 534 patients managed nonoperatively. LEVEL OF EVIDENCE: Level II, Prognosis.

The impact of inverted text on visual word processing: An fMRI study.

Visual word recognition has been studied for decades. One question that has received limited attention is how different text presentation orientations disrupt word recognition. By examining how word recognition processes may be disrupted by different text orientations it is hoped that new insights can be gained concerning the process. Here, we examined the impact of rotating and inverting text on the neural network responsible for visual word recognition focusing primarily on a region of the occipto-temporal cortex referred to as the visual word form area (VWFA). A lexical decision task was employed in which words and pseudowords were presented in one of three orientations (upright, rotated or inverted). The results demonstrate that inversion caused the greatest disruption of visual word recognition processes. Both rotated and inverted text elicited increased activation in spatial attention regions within the right parietal cortex. However, inverted text recruited phonological and articulatory processing regions within the left inferior frontal and left inferior parietal cortices. Finally, the VWFA was found to not behave similarly to the fusiform face area in that unusual text orientations resulted in increased activation and not decreased activation. It is hypothesized here that the VWFA activation is modulated by feedback from linguistic processes.

Different mechanisms in learning different second languages: Evidence from English speakers learning Chinese and Spanish.

Word reading has been found to be associated with different neural networks in different languages, with greater involvement of the lexical pathway for opaque languages and greater invovlement of the sub-lexical pathway for transparent langauges. However, we do not know whether this language divergence can be demonstrated in second langauge learners, how learner's metalinguistic ability would modulate the langauge divergence, or whether learning method would interact with the language divergence. In this study, we attempted to answer these questions by comparing brain activations of Chinese and Spanish word reading in native English-speaking adults who learned Chinese and Spanish over a 2 week period under three learning conditions: phonological, handwriting, and passive viewing. We found that mapping orthography to phonology in Chinese had greater activation in the left inferior frontal gyrus (IFG) and left inferior temporal gyrus (ITG) than in Spanish, suggesting greater invovlement of the lexical pathway in opaque langauges. In contrast, Spanish words evoked greater activation in the left superior temporal gyrus (STG) than English, suggesting greater invovlement of the sublexical pathway for transparant languages. Furthermore, brain-behavior correlation analyses found that higher phonological awareness and rapid naming were associated with greater activation in the bilateral IFG for Chinese and in the bilateral STG for Spanish, suggesting greater language divergence in participants with higher meta-linguistic awareness. Finally, a significant interaction between the language and learning condition was found in the left STG and middle frontal gyrus (MFG), with greater activation in handwriting learning than viewing learning in the left STG only for Spanish, and greater activation in handwriting learning than phonological learning in the left MFG only for Chinese. These findings suggest that handwriting facilitates assembled phonology in Spanish and addressed phonology in Chinese. In summary, our study suggests different mechanisms in learning different L2s, providing important insights into neural plasticity and important implications in second language education.

Dyslexia and configural perception of character sequences.

Developmental dyslexia is a complex and heterogeneous disorder characterized by unexpected difficulty in learning to read. Although it is considered to be biologically based, the degree of variation has made the nature and locus of dyslexia difficult to ascertain. Hypotheses regarding the cause have ranged from low-level perceptual deficits to higher order cognitive deficits, such as phonological processing and visual-spatial attention. We applied the capacity coefficient, a measure obtained from a mathematical cognitive model of response times to measure how efficiently participants processed different classes of stimuli. The capacity coefficient was used to test the extent to which individuals with dyslexia can be distinguished from normal reading individuals based on their ability to take advantage of word, pronounceable non-word, consonant sequence or unfamiliar context when categorizing character strings. Within subject variability of the capacity coefficient across character string types was fairly regular across normal reading adults and consistent with a previous study of word perception with the capacity coefficient-words and pseudowords were processed at super-capacity and unfamiliar characters strings at limited-capacity. Two distinct patterns were observed in individuals with dyslexia. One group had a profile similar to the normal reading adults while the other group showed very little variation in capacity across string-type. It is possible that these individuals used a similar strategy for all four string-types and were able to generalize this strategy when processing unfamiliar characters. This difference across dyslexia groups may be used to identify sub-types of the disorder and suggest significant differences in word level processing among these subtypes. Therefore, this approach may be useful in further delineating among types of dyslexia, which in turn may lead to better understanding of the etiologies of dyslexia.