Integer partitions detect the primes.

We show that integer partitions, the fundamental building blocks in additive number theory, detect prime numbers in an unexpected way. Answering a question of Schneider, we show that the primes are the solutions to special equations in partition functions. For example, an integer n ≥ 2 is prime if and only if [Formula: see text]where the [Formula: see text] are MacMahon's well-studied partition functions. More generally, for MacMahonesque partition functions [Formula: see text] we prove that there are infinitely many such prime detecting equations with constant coefficients, such as [Formula: see text].

Stakeholder engagement to develop a directory of COVID-19 related mental health services in Vietnam: reflections on a participatory approach.

The COVID-19 pandemic led to a rise of mental health issues amongst Vietnamese communities in Vietnam and the diaspora. However, there were few resources and no directory of services available for people seeking mental health support in Vietnam. In response to this need, we initiated an engagement project to improve Vietnamese communities' access to mental health support. This project aimed to involve stakeholders in the development of a directory of resources in order to ensure that it met local needs. The phases of development included: (1) reviewing desk research findings; (2) reviewing the list of mental health support services that we could find; (3) verifying the first draft of the directory; (4) helping disseminate the directory; and (5) updating the directory. In February 2022 the first edition of the mental health directory for Vietnamese and foreigners living in Vietnam was published. In this paper we describe the iterative approach taken to developing a resource that would have maximum utility for the target communities. We describe the process of partnering with people with lived experience, community members and expert stakeholders in this process, and reflect on how this strengthened the outcomes in terms of the relevance of the output, the research uptake and the access for the wider community. We believe that it is important to publish examples of community engagement projects in order to demonstrate good practise and promote increased involvement of communities in research.

The COVID-19 pandemic led to a rise of mental health issues amongst Vietnamese communities in Vietnam and those living overseas. However, there are few resources and no directory of services available for people seeking mental health support in Vietnam. In response to this need, the public engagement team at the Oxford University Clinical Research Unit in Ho Chi Minh city, Vietnam, worked with local experts and community groups to create a directory of resources available to support mental health. In February 2022, the first edition of the mental health directory for Vietnamese and foreigners living in Vietnam was published. In this paper, we describe the steps we took to developing the resource. We describe the process of partnering with people with lived experience, community members and expert stakeholders in this process, and reflect how their involvement helped create a more relevant resource.

Association of Psychological Resilience, Cognitive Reserve, and Brain Reserve with Post-Concussive Symptoms in Children with Mild Traumatic Brain Injury and Orthopedic Injury: An A-CAP Study.

Protective factors, including psychological resilience, cognitive reserve, and brain reserve, may be positively associated with recovery after pediatric mild traumatic brain injury (mTBI) but are yet to be studied concurrently. We sought to examine these factors as moderators of post-concussive symptoms (PCS) in pediatric mTBI compared with mild orthopedic injury (OI). Participants included 967 children (633 mTBI, 334 OI) aged 8-16.99 years, recruited from 5 Canadian pediatric emergency departments as part of a prospective longitudinal cohort study. At 10 days post-injury, psychological resilience was measured using the Connor-Davidson Resilience Scale and brain reserve was measured using total brain volume derived from structural magnetic resonance imaging. Cognitive reserve was measured at 3 months post-injury using IQ scores from the Wechsler Abbreviated Scale of Intelligence-Second Edition. Cognitive and somatic PCS were measured using child and parent ratings on the Health and Behavior Inventory, completed weekly for 3 months and biweekly to 6 months. Analyses involved generalized least-squares regression models using restricted cubic splines. Covariates included age at injury, sex, racialized identity, material and social deprivation, pre-injury migraine and concussion history, and retrospective pre-injury PCS. Psychological resilience moderated group differences in parent-reported PCS. At 30 days post-injury, estimated group differences in parent-reported cognitive and somatic PCS (mTBI > OI) were larger at higher (75th percentile) resilience scores (Est = 2.25 [0.87, 3.64] and Est = 2.38 [1.76, 3.00], respectively) than at lower (25th percentile) resilience scores (Est = 1.44 [0.01, 2.86] and Est = 2.08 [1.45, 2.71], respectively). Resilience did not moderate group differences in child-reported PCS but was negatively associated with child-reported PCS in both groups (ps ≤ 0.001). Brain reserve (i.e., total brain volume [TBV]) also moderated group differences, but only for parent-reported somatic PCS (p = 0.018). Group difference (mTBI > OI) at 30 days was larger at smaller (25th percentile) TBV (Est = 2.78 [2.17, 3.38]) than at larger (75th percentile) TBV (Est = 1.95 [1.31, 2.59]). TBV was not associated with parent-reported cognitive PCS or child-reported PCS. IQ did not moderate PCS in either group but had a significant non-linear association in both groups with child-reported somatic PCS (p = 0.018) and parent-reported PCS (p < 0.001), with higher PCS scores at both lower and higher IQs. These findings suggest that higher resilience predicts fewer PCS, but less strongly after mTBI than OI; greater brain reserve may reduce the effect of mTBI on somatic PCS; and cognitive reserve has an unexpected curvilinear association with PCS across injury types. The results highlight the importance of protective factors as predictors of recovery and potential targets for intervention following pediatric mTBI.

Global abundance patterns, diversity, and ecology of Patescibacteria in wastewater treatment plants.

BACKGROUND: Microorganisms are responsible for nutrient removal and resource recovery in wastewater treatment plants (WWTPs), and their diversity is often studied by 16S rRNA gene amplicon sequencing. However, this approach underestimates the abundance and diversity of Patescibacteria due to the low coverage of commonly used PCR primers for this highly divergent bacterial phylum. Therefore, our current understanding of the global diversity, distribution, and ecological role of Patescibacteria in WWTPs is very incomplete. This is particularly relevant as Patescibacteria are considered to be associated with microbial host cells and can therefore influence the abundance and temporal variability of other microbial groups that are important for WWTP functioning. RESULTS: Here, we evaluated the in silico coverage of widely used 16S rRNA gene-targeted primer pairs and redesigned a primer pair targeting the V4 region of bacterial and archaeal 16S rRNA genes to expand its coverage for Patescibacteria. We then experimentally evaluated and compared the performance of the original and modified V4-targeted primers on 565 WWTP samples from the MiDAS global sample collection. Using the modified primer pair, the percentage of ASVs classified as Patescibacteria increased from 5.9 to 23.8%, and the number of detected patescibacterial genera increased from 560 to 1576, while the detected diversity of the remaining microbial community remained similar. Due to this significantly improved coverage of Patescibacteria, we identified 23 core genera of Patescibacteria in WWTPs and described the global distribution pattern of these unusual microbes in these systems. Finally, correlation network analysis revealed potential host organisms that might be associated with Patescibacteria in WWTPs. Interestingly, strong indications were found for an association between Patescibacteria of the Saccharimonadia and globally abundant polyphosphate-accumulating organisms of the genus Ca. Phosphoribacter. CONCLUSIONS: Our study (i) provides an improved 16S rRNA gene V4 region-targeted amplicon primer pair inclusive of Patescibacteria with little impact on the detection of other taxa, (ii) reveals the diversity and distribution patterns of Patescibacteria in WWTPs on a global scale, and (iii) provides new insights into the ecological role and potential hosts of Patescibacteria in WWTPs. Video Abstract.

Do preinjury life events moderate the outcomes of mild traumatic brain injuries in children? An A-CAP Study.

OBJECTIVE: To examine preinjury life events as moderators of postconcussive symptoms (PCS) and quality of life (QoL) in children with pediatric mild traumatic brain injury (mTBI) versus orthopedic injury (OI). METHODS: Participants were 633 children with mTBI and 334 with OI, ages 8-16.99, recruited from 5 pediatric emergency departments and followed for 6 months postinjury as part of a prospective cohort study. Preinjury life events were measured retrospectively using the Child and Adolescent Survey of Experiences, PCS using the Health and Behavior Inventory (HBI) and Post-Concussion Symptom Interview (PCS-I), and QoL using the Pediatric Quality of Life Inventory (PedsQL). Analyses involved longitudinal regression using restricted cubic splines, with group, positive and negative life events, and time as primary predictors. Covariates included age, sex, race, socioeconomic status, preinjury history (i.e., headache, migraine, previous concussion), and parent-rated retrospective PCS-I, HBI, and PedsQL scores. RESULTS: PCS and QoL were worse after mTBI than OI, but group differences declined with time (all p < .001). Group differences in PCS were larger at higher levels of positive life events, which predicted lower PCS (p= .03 to p < .001) and higher QoL (p = .048) after OI but not after mTBI. Negative life events predicted worse PCS and QoL in both groups (p = .002 to p < .001). CONCLUSIONS: Preinjury positive life events moderate outcomes after pediatric injury, with a protective effect seen in OI but not in mTBI. Negative life events are consistently associated with worse outcomes regardless of injury type.

Longitudinal changes in brain metabolites following pediatric concussion.

Concussion is commonly characterized by a cascade of neurometabolic changes following injury. Magnetic Resonance Spectroscopy (MRS) can be used to quantify neurometabolites non-invasively. Longitudinal changes in neurometabolites have rarely been studied in pediatric concussion, and fewer studies consider symptoms. This study examines longitudinal changes of neurometabolites in pediatric concussion and associations between neurometabolites and symptom burden. Participants who presented with concussion or orthopedic injury (OI, comparison group) were recruited. The first timepoint for MRS data collection was at a mean of 12 days post-injury (n = 545). Participants were then randomized to 3 (n = 243) or 6 (n = 215) months for MRS follow-up. Parents completed symptom questionnaires to quantify somatic and cognitive symptoms at multiple timepoints following injury. There were no significant changes in neurometabolites over time in the concussion group and neurometabolite trajectories did not differ between asymptomatic concussion, symptomatic concussion, and OI groups. Cross-sectionally, Choline was significantly lower in those with persistent somatic symptoms compared to OI controls at 3 months post-injury. Lower Choline was also significantly associated with higher somatic symptoms. Although overall neurometabolites do not change over time, choline differences that appear at 3 months and is related to somatic symptoms.

Dynamic Relations Between Psychological Resilience and Post-Concussion Symptoms in Children With Mild Traumatic Brain Injury Versus Orthopedic Injury: An A-CAP Study.

Higher psychological resilience is correlated with less severe post-concussion symptoms (PCS) after mild traumatic brain injury (mTBI) in children, but the directional nature of this relationship remains uncertain. Although traditionally regarded as a stable, trait-like construct, resilience may be malleable and potentially influenced by mTBI and post-concussive symptoms. The current study sought to examine the stability of resilience, elucidate the dynamic nature of the resilience-PCS relation, and determine whether resilience-symptom associations are specific to mTBI or applicable to traumatic injury in general. Participants were children aged 8-16.99 years with either mTBI (n = 633) or orthopedic injury (OI; n = 334) recruited to participate in a prospective cohort study after presenting acutely to five Canadian pediatric emergency departments (EDs). Symptoms and psychological resilience were assessed at 1 week, 3 months, and 6 months post-injury. Group differences in resilience over time were examined using a mixed linear model, and associations between resilience and symptoms over time were examined using random intercepts cross-lagged panel modeling (RI-CLPM). The mTBI group reported significantly lower resilience than the OI group, but the difference was significantly larger 1 week post-injury (d = 0.50) than at 3 months (d = 0.08) and 6 months (d = 0.10). Cross-lagged panel models indicated that resilience had both stable and dynamic aspects, and both affected and was affected by PCS, although their association varied by time post-injury, symptom measure, and reporter (parent vs. child). Higher parent-reported cognitive symptom severity at 1 week was significantly associated with higher resilience at 3 months (ß = 0.23, p = 0.001). Higher resilience at 3 months was associated with lower levels of parent-reported somatic symptom severity (ß = -0.14, p = 0.004) and fewer total symptoms (ß = -0.135, p = 0.029) at 6 months. Higher resilience at 3 months was associated with fewer child-reported symptoms at 6 months (ß = -0.11, p = 0.030) and, reciprocally, fewer child-reported symptoms at 3 months were associated with higher resilience at 6 months (ß = -0.22, p = 0.001). Notably, injury group was not a significant moderator in cross-lagged models, suggesting that resilience-symptom associations are not specific to mTBI. Psychological resilience and symptoms have bidirectional relationships after injury. Interventions designed to foster resilience have the potential to promote recovery after mTBI specifically and injury more generally.

Longitudinal Functional Connectome in Pediatric Concussion: An Advancing Concussion Assessment in Pediatrics Study.

Advanced magnetic resonance imaging (MRI) techniques indicate that concussion (i.e., mild traumatic brain injury) disrupts brain structure and function in children. However, the functional connectivity of brain regions within global and local networks (i.e., functional connectome) is poorly understood in pediatric concussion. This prospective, longitudinal study addressed this gap using data from the largest neuroimaging study of pediatric concussion to date to study the functional connectome longitudinally after concussion as compared with mild orthopedic injury (OI). Children and adolescents (n = 967) 8-16.99 years with concussion or mild OI were recruited from pediatric emergency departments within 48 h post-injury. Pre-injury and 1-month post-injury symptom ratings were used to classify concussion with or without persistent symptoms based on reliable change. Subjects completed a post-acute (2-33 days) and chronic (3 or 6 months via random assignment) MRI scan. Graph theory metrics were derived from 918 resting-state functional MRI scans in 585 children (386 concussion/199 OI). Linear mixed-effects modeling was performed to assess group differences over time, correcting for multiple comparisons. Relative to OI, the global clustering coefficient was reduced at 3 months post-injury in older children with concussion and in females with concussion and persistent symptoms. Time post-injury and sex moderated group differences in local (regional) network metrics of several brain regions, including degree centrality, efficiency, and clustering coefficient of the angular gyrus, calcarine fissure, cuneus, and inferior occipital, lingual, middle occipital, post-central, and superior occipital gyrus. Relative to OI, degree centrality and nodal efficiency were reduced post-acutely, and nodal efficiency and clustering coefficient were reduced chronically after concussion (i.e., at 3 and 6 months post-injury in females; at 6 months post-injury in males). Functional network alterations were more robust and widespread chronically as opposed to post-acutely after concussion, and varied by sex, age, and symptom recovery at 1-month post-injury. Local network segregation reductions emerged globally (across the whole brain network) in older children and in females with poor recovery chronically after concussion. Reduced functioning between neighboring regions could negatively disrupt specialized information processing. Local network metric alterations were demonstrated in several posterior regions that are involved in vision and attention after concussion relative to OI. This indicates that functioning of superior parietal and occipital regions could be particularly susceptibile to the effects of concussion. Moreover, those regional alterations were especially apparent at later time periods post-injury, emerging after post-concussive symptoms resolved in most and persisted up to 6 months post-injury, and differed by biological sex. This indicates that neurobiological changes continue to occur up to 6 months after pediatric concussion, although changes emerge earlier in females than in males. Changes could reflect neural compensation mechanisms.

Autonomic Cardioregulatory Function Does Not Correlate With Symptom Improvement After Concussion in Children and Adolescents.

Although there is significant variability in the manifestations of persisting post-concussive symptoms (PPCS), autonomic dysfunction has been reported to contribute to PPCS and could serve as a biomarker of recovery. The objective of this study was to evaluate cardiac autonomic reflexes and autonomic function after concussion injury comparing those with prolonged concussion symptoms to those without. This is a case-control study where a non-referred population of concussed children or adolescent participants were enrolled from the Emergency Department (ED) of the Stollery Children's Hospital, a tertiary pediatric hospital in Edmonton, Alberta, Canada. Children and adolescents 8 through <18 years of age who presented with mild traumatic brain injury were diagnosed with concussion. Our study reported concussion symptoms and standardized clinical cardiac autonomic reflex testing at 4 and 12 weeks after injury. Our findings showed that 28 participants with concussion completed the 4-week follow-up questionnaires, and that 17 (61%) were diagnosed with PPCS. Difficulty concentrating, fatigue, noise sensitivity, light sensitivity, and headache were most commonly reported at baseline among those who were later diagnosed with PPCS. The mean change in heart rate (HR) with head-up tilt was 44.2 bpm (standard deviation [SD] 9.1) in the non-PPCS group and 46.6 bpm (SD 14.1) in the PPCS group at 4 weeks and was not significant in the unadjusted (p = 0.2) or adjusted analysis for age and female sex (p = 0.2). Overall, 70% (19/27) had significant orthostatic tachycardia >40 bpm, but PPCS and non-PPCS groups were similar. Similar results were observed among 23 participants at 12-week follow-up. The median maximum decrease in systolic blood pressure (SBP) with head-up tilt was -26.9 mm Hg (interquartile range [IQR] -32.6, -22.3) in the non-PPCS group and -25.1 mm Hg (IQR -32.2, -18.2) in the PPCS group, and was not significantly different in the unadjusted (p = 0.8) or adjusted (p = 0.8) analysis. Overall, 19 of 26 participants (73%) demonstrated orthostatic hypotension (SBP change >20 mm Hg) with no significant difference between the PPCS and non-PPCS groups. Similar results were observed at 12-week follow-up. In conclusion, cardiac autonomic reflex responses are abnormal in most children and adolescents with a concussion injury at 4- and 12-week follow-up and may reflect ongoing autonomic dysfunction. However, autonomic function did not differentiate PPCS, indicating that reported symptoms are not sensitive to autonomic abnormalities.

IQ After Pediatric Concussion.

OBJECTIVES: This study investigated IQ scores in pediatric concussion (ie, mild traumatic brain injury) versus orthopedic injury. METHODS: Children (N = 866; aged 8-16.99 years) were recruited for 2 prospective cohort studies from emergency departments at children's hospitals (2 sites in the United States and 5 in Canada) ≤48 hours after sustaining a concussion or orthopedic injury. They completed IQ and performance validity testing postacutely (3-18 days postinjury; United States) or 3 months postinjury (Canada). Group differences in IQ scores were examined using 3 complementary statistical approaches (linear modeling, Bayesian, and multigroup factor analysis) in children performing above cutoffs on validity testing. RESULTS: Linear models showed small group differences in full-scale IQ (d [95% confidence interval] = 0.13 [0.00-0.26]) and matrix reasoning (0.16 [0.03-0.30]), but not in vocabulary scores. IQ scores were not related to previous concussion, acute clinical features, injury mechanism, a validated clinical risk score, pre- or postinjury symptom ratings, litigation, or symptomatic status at 1 month postinjury. Bayesian models provided moderate to very strong evidence against group differences in IQ scores (Bayes factor 0.02-0.23). Multigroup factor analysis further demonstrated strict measurement invariance, indicating group equivalence in factor structure of the IQ test and latent variable means. CONCLUSIONS: Across multisite, prospective study cohorts, 3 complementary statistical models provided no evidence of clinically meaningful differences in IQ scores after pediatric concussion. Instead, overall results provided strong evidence against reduced intelligence in the first few weeks to months after pediatric concussion.

Altered longitudinal structural connectome in paediatric mild traumatic brain injury: an Advancing Concussion Assessment in Paediatrics study.

Advanced diffusion-weighted imaging techniques have increased understanding of the neuropathology of paediatric mild traumatic brain injury (i.e. concussion). Most studies have examined discrete white-matter pathways, which may not capture the characteristically subtle, diffuse and heterogenous effects of paediatric concussion on brain microstructure. This study compared the structural connectome of children with concussion to those with mild orthopaedic injury to determine whether network metrics and their trajectories across time post-injury differentiate paediatric concussion from mild traumatic injury more generally. Data were drawn from of a large study of outcomes in paediatric concussion. Children aged 8-16.99 years were recruited from five paediatric emergency departments within 48 h of sustaining a concussion (n = 360; 56% male) or mild orthopaedic injury (n = 196; 62% male). A reliable change score was used to classify children with concussion into two groups: concussion with or without persistent symptoms. Children completed 3 T MRI at post-acute (2-33 days) and/or chronic (3 or 6 months, via random assignment) post-injury follow-ups. Diffusion-weighted images were used to calculate the diffusion tensor, conduct deterministic whole-brain fibre tractography and compute connectivity matrices in native (diffusion) space for 90 supratentorial regions. Weighted adjacency matrices were constructed using average fractional anisotropy and used to calculate global and local (regional) graph theory metrics. Linear mixed effects modelling was performed to compare groups, correcting for multiple comparisons. Groups did not differ in global network metrics. However, the clustering coefficient, betweenness centrality and efficiency of the insula, cingulate, parietal, occipital and subcortical regions differed among groups, with differences moderated by time (days) post-injury, biological sex and age at time of injury. Post-acute differences were minimal, whereas more robust alterations emerged at 3 and especially 6 months in children with concussion with persistent symptoms, albeit differently by sex and age. In the largest neuroimaging study to date, post-acute regional network metrics distinguished concussion from mild orthopaedic injury and predicted symptom recovery 1-month post-injury. Regional network parameters alterations were more robust and widespread at chronic timepoints than post-acutely after concussion. Results suggest that increased regional and local subnetwork segregation (modularity) and inefficiency occurs across time after concussion, emerging after post-concussive symptom resolve in most children. These differences persist up to 6 months after concussion, especially in children who showed persistent symptoms. While prognostic, the small to modest effect size of group differences and the moderating effects of sex likely would preclude effective clinical application in individual patients.

Longitudinal Gray Matter Trajectories in Pediatric Mild Traumatic Brain Injury.

BACKGROUND AND OBJECTIVES: This prospective, longitudinal cohort study examined trajectories of brain gray matter macrostructure after pediatric mild traumatic brain injury (mTBI). METHODS: Children aged 8-16.99 years with mTBI or mild orthopedic injury (OI) were recruited from 5 pediatric emergency departments. Reliable change between preinjury and 1 month postinjury symptom ratings was used to classify mTBI with or without persistent symptoms. Children completed postacute (2-33 days) and/or chronic (3 or 6 months) postinjury T1-weighted MRI, from which macrostructural metrics were derived using automated segmentation. Linear mixed-effects models were used, with multiple comparisons correction. RESULTS: Groups (N = 623; 407 mTBI/216 OI; 59% male; age mean = 12.03, SD = 2.38 years) did not differ in total brain, white, or gray matter volumes or regional subcortical gray matter volumes. However, time postinjury, age at injury, and biological sex-moderated differences among symptom groups in cortical thickness of the angular gyrus, basal forebrain, calcarine cortex, gyrus rectus, medial and posterior orbital gyrus, and the subcallosal area all corrected p < 0.05. Gray matter macrostructural metrics did not differ between groups postacutely. However, cortical thinning emerged chronically after mTBI relative to OI in the angular gyrus in older children (d [95% confidence interval] = -0.61 [-1.15 to -0.08]); and in the basal forebrain (-0.47 [-0.94 to -0.01]), subcallosal area (-0.55 [-1.01 to -0.08]), and the posterior orbital gyrus (-0.55 [-1.02 to -0.08]) in females. Cortical thinning was demonstrated for frontal and occipital regions 3 months postinjury in males with mTBI with persistent symptoms vs without persistent symptoms (-0.80 [-1.55 to -0.05] to -0.83 [-1.56 to -0.10]) and 6 months postinjury in females and younger children with mTBI with persistent symptoms relative to mTBI without persistent symptoms and OI (-1.42 [-2.29 to -0.45] to -0.91 [-1.81 to -0.01]). DISCUSSION: These findings signal little diagnostic and prognostic utility of postacute gray matter macrostructure in pediatric mTBI. However, mTBI altered the typical course of cortical gray matter thinning up to 6 months postinjury, even after symptoms typically abate in most children. Collapsing across symptom status obscured the neurobiological heterogeneity of discrete clinical outcomes after pediatric mTBI. The results illustrate the need to examine neurobiology in relation to clinical outcomes and within a neurodevelopmental framework.

Comparison of different approaches to manage multi-site magnetic resonance spectroscopy clinical data analysis.

Introduction: The effects caused by differences in data acquisition can be substantial and may impact data interpretation in multi-site/scanner studies using magnetic resonance spectroscopy (MRS). Given the increasing use of multi-site studies, a better understanding of how to account for different scanners is needed. Using data from a concussion population, we compare ComBat harmonization with different statistical methods in controlling for site, vendor, and scanner as covariates to determine how to best control for multi-site data. Methods: The data for the current study included 545 MRS datasets to measure tNAA, tCr, tCho, Glx, and mI to study the pediatric concussion acquired across five sites, six scanners, and two different MRI vendors. For each metabolite, the site and vendor were accounted for in seven different models of general linear models (GLM) or mixed-effects models while testing for group differences between the concussion and orthopedic injury. Models 1 and 2 controlled for vendor and site. Models 3 and 4 controlled for scanner. Models 5 and 6 controlled for site applied to data harmonized by vendor using ComBat. Model 7 controlled for scanner applied to data harmonized by scanner using ComBat. All the models controlled for age and sex as covariates. Results: Models 1 and 2, controlling for site and vendor, showed no significant group effect in any metabolites, but the vendor and site were significant factors in the GLM. Model 3, which included a scanner, showed a significant group effect for tNAA and tCho, and the scanner was a significant factor. Model 4, controlling for the scanner, did not show a group effect in the mixed model. The data harmonized by the vendor using ComBat (Models 5 and 6) had no significant group effect in both the GLM and mixed models. Lastly, the data harmonized by the scanner using ComBat (Model 7) showed no significant group effect. The individual site data suggest there were no group differences. Conclusion: Using data from a large clinical concussion population, different analysis techniques to control for site, vendor, and scanner in MRS data yielded different results. The findings support the use of ComBat harmonization for clinical MRS data, as it removes the site and vendor effects.

Association of Posttraumatic Headache With Symptom Burden After Concussion in Children.

Importance: Headache is the most common symptom after pediatric concussion. Objectives: To examine whether posttraumatic headache phenotype is associated with symptom burden and quality of life 3 months after concussion. Design, Setting, and Participants: This was a secondary analysis of the Advancing Concussion Assessment in Pediatrics (A-CAP) prospective cohort study, conducted September 2016 to July 2019 at 5 Pediatric Emergency Research Canada (PERC) network emergency departments. Children aged 8.0-16.99 years presenting with acute (<48 hours) concussion or orthopedic injury (OI) were included. Data were analyzed from April to December 2022. Exposure: Posttraumatic headache was classified as migraine or nonmigraine headache, or no headache, using modified International Classification of Headache Disorders, 3rd edition, diagnostic criteria based on self-reported symptoms collected within 10 days of injury. Main Outcomes and Measures: Self-reported postconcussion symptoms and quality-of-life were measured at 3 months after concussion using the validated Health and Behavior Inventory (HBI) and Pediatric Quality of Life Inventory-Version 4.0 (PedsQL-4.0). An initial multiple imputation approach was used to minimize potential biases due to missing data. Multivariable linear regression evaluated the association between headache phenotype and outcomes compared with the Predicting and Preventing Postconcussive Problems in Pediatrics (5P) clinical risk score and other covariates and confounders. Reliable change analyses examined clinical significance of findings. Results: Of 967 enrolled children, 928 (median [IQR] age, 12.2 [10.5 to 14.3] years; 383 [41.3%] female) were included in analyses. HBI total score (adjusted) was significantly higher for children with migraine than children without headache (estimated mean difference [EMD], 3.36; 95% CI, 1.13 to 5.60) and children with OI (EMD, 3.10; 95% CI, 0.75 to 6.62), but not children with nonmigraine headache (EMD, 1.93; 95% CI, -0.33 to 4.19). Children with migraine were more likely to report reliable increases in total symptoms (odds ratio [OR], 2.13; 95% CI, 1.02 to 4.45) and somatic symptoms (OR, 2.70; 95% CI, 1.29 to 5.68) than those without headache. PedsQL-4.0 subscale scores were significantly lower for children with migraine than those without headache only for physical functioning (EMD, -4.67; 95% CI, -7.86 to -1.48). Conclusions and Relevance: In this cohort study of children with concussion or OI, those with posttraumatic migraine symptoms after concussion had higher symptom burden and lower quality of life 3 months after injury than those with nonmigraine headache. Children without posttraumatic headache reported the lowest symptom burden and highest quality of life, comparable with children with OI. Further research is warranted to determine effective treatment strategies that consider headache phenotype.

Brain metabolites measured with magnetic resonance spectroscopy in pediatric concussion and orthopedic injury: An Advancing Concussion Assessment in Pediatrics (A-CAP) study.

Millions of children sustain a concussion annually. Concussion disrupts cellular signaling and neural pathways within the brain but the resulting metabolic disruptions are not well characterized. Magnetic resonance spectroscopy (MRS) can examine key brain metabolites (e.g., N-acetyl Aspartate (tNAA), glutamate (Glx), creatine (tCr), choline (tCho), and myo-Inositol (mI)) to better understand these disruptions. In this study, we used MRS to examine differences in brain metabolites between children and adolescents with concussion versus orthopedic injury. Children and adolescents with concussion (n = 361) or orthopedic injury (OI) (n = 184) aged 8 to 17 years were recruited from five emergency departments across Canada. MRS data were collected from the left dorsolateral prefrontal cortex (L-DLPFC) using point resolved spectroscopy (PRESS) at 3 T at a mean of 12 days post-injury (median 10 days post-injury, range 2-33 days). Univariate analyses for each metabolite found no statistically significant metabolite differences between groups. Within each analysis, several covariates were statistically significant. Follow-up analyses designed to account for possible confounding factors including age, site, scanner, vendor, time since injury, and tissue type (and interactions as appropriate) did not find any metabolite group differences. In the largest sample of pediatric concussion studied with MRS to date, we found no metabolite differences between concussion and OI groups in the L-DLPFC. We suggest that at 2 weeks post-injury in a general pediatric concussion population, brain metabolites in the L-DLPFC are not specifically affected by brain injury.

Association Between Early Return to School Following Acute Concussion and Symptom Burden at 2 Weeks Postinjury.

Importance: Determining how the timing of return to school is related to later symptom burden is important for early postinjury management recommendations. Objective: To examine the typical time to return to school after a concussion and evaluate whether an earlier return to school is associated with symptom burden 14 days postinjury. Design, Setting, and Participants: Planned secondary analysis of a prospective, multicenter observational cohort study from August 2013 to September 2014. Participants aged 5 to 18 years with an acute (<48 hours) concussion were recruited from 9 Canadian pediatric emergency departments in the Pediatric Emergency Research Canada Network. Exposure: The independent variable was the number of days of school missed. Missing fewer than 3 days after concussion was defined as an early return to school. Main Outcomes and Measures: The primary outcome was symptom burden at 14 days, measured with the Post-Concussion Symptom Inventory (PCSI). Symptom burden was defined as symptoms status at 14 days minus preinjury symptoms. Propensity score analyses applying inverse probability of treatment weighting were performed to estimate the relationship between the timing of return to school and symptom burden. Results: This cohort study examined data for 1630 children (mean age [SD] 11.8 [3.4]; 624 [38%] female). Of these children, 875 (53.7%) were classified as having an early return to school. The mean (SD) number of days missed increased across age groups (5-7 years, 2.61 [5.2]; 8-12 years, 3.26 [4.9]; 13-18 years, 4.71 [6.1]). An early return to school was associated with a lower symptom burden 14 days postinjury in the 8 to 12-year and 13 to 18-year age groups, but not in the 5 to 7-year age group. The association between early return and lower symptom burden was stronger in individuals with a higher symptom burden at the time of injury, except those aged 5 to 7 years. Conclusions and Relevance: In this cohort study of youth aged 5 to 18 years, these results supported the growing belief that prolonged absences from school and other life activities after a concussion may be detrimental to recovery. An early return to school may be associated with a lower symptom burden and, ultimately, faster recovery.

A Prospective Cohort Study of the Association Between Preinjury Psychosocial Function and Postconcussive Symptoms in Pediatric Mild Traumatic Brain Injury: An A-CAP Study.

OBJECTIVE: We evaluated the moderating effect of preinjury psychosocial function on postconcussion symptoms for children with mild traumatic brain injury (mTBI). DESIGN, SETTING, AND POPULATION: We conducted a prospective cohort study of children ages 8.0 to 16.9 years with mTBI ( n = 633) or orthopedic injury (OI; n = 334), recruited from 5 pediatric emergency departments from September 2016 to December 2018. MAIN MEASURES: Participants completed baseline assessments within 48 hours of injury, and postconcussion symptoms assessments at 7 to 10 days, weekly to 3 months, and biweekly to 6 months post-injury. Preinjury psychosocial function was measured using parent ratings on the Pediatric Quality of Life Inventory (PedsQL) and the Strengths and Difficulties Questionnaire (SDQ), retrospectively evaluating their child's status prior to the injury. Parent and child ratings on the Health and Behavior Inventory (HBI) (cognitive and somatic subscales) and the Post-Concussion Symptom Interview (PCS-I) were used as measures of postconcussion symptoms. We fitted 6 longitudinal regression models, which included 747 to 764 participants, to evaluate potential interactions between preinjury psychosocial function and injury group as predictors of child- and parent-reported postconcussion symptoms. RESULTS: Preinjury psychosocial function moderated group differences in postconcussion symptoms across the first 6 months post-injury. Higher emotional and conduct problems were significantly associated with more severe postconcussion symptoms among children with mTBI compared with OI. Wald's χ 2 for interaction terms (injury group × SDQ subscales) ranged from 6.3 to 10.6 ( P values <.001 to .043) across parent- and child-reported models. In contrast, larger group differences (mTBI > OI) in postconcussion symptoms were associated with milder hyperactivity (Wald's χ 2 : 15.3-43.0, all P < .001), milder peer problems (Wald's χ 2 : 11.51, P = .003), and higher social functioning (Wald's χ 2 : 12.435, P = .002). CONCLUSIONS: Preinjury psychosocial function moderates postconcussion symptoms in pediatric mTBI, highlighting the importance of assessing preinjury psychosocial function in children with mTBI.

Can quantitative susceptibility mapping help diagnose and predict recovery of concussion in children? An A-CAP study.

BACKGROUND: Quantitative susceptibility mapping (QSM) is an MRI technique that is a potential biomarker for concussion. We performed QSM in children following concussion or orthopaedic injury (OI), to assess QSM performance as a diagnostic and prognostic biomarker. METHODS: Children aged 8-17 years with either concussion (N=255) or OI (N=116) were recruited from four Canadian paediatric emergency departments and underwent QSM postacutely (2-33 days postinjury) using 3 Tesla MRI. QSM Z-scores within nine regions of interest (ROI) were compared between groups. QSM Z-scores were also compared with the 5P score, the current clinical benchmark for predicting persistent postconcussion symptoms (PPCS), at 4 weeks postinjury, with PPCS defined using reliable change methods based on both participant and parent reports. RESULTS: Concussion and OI groups did not differ significantly in QSM Z-scores for any ROI. Higher QSM Z-scores within frontal white matter (WM) independently predicted PPCS based on parent ratings of cognitive symptoms (p=0.001). The combination of frontal WM QSM Z-score and 5P score was better at predicting PPCS than 5P score alone (p=0.004). The area under the curve was 0.72 (95% CI 0.63 to 0.81) for frontal WM susceptibility, 0.69 (95% CI 0.59 to 0.79) for the 5P score and 0.74 (95% CI 0.65 to 0.83) for both. CONCLUSION: The findings suggest that QSM is a potential MRI biomarker that can help predict PPCS in children with concussion, over and above the current clinical benchmark, and thereby aid in clinical management. They also suggest a frontal lobe substrate for PPCS, highlighting the potential for QSM to clarify the neurophysiology of paediatric concussion.

Factor structure and measurement invariance of post-concussion symptom ratings on the Health and Behaviour Inventory across time, raters, and groups: An A-CAP study.

OBJECTIVES: To validate the two-factor structure (i.e., cognitive and somatic) of the Health and Behaviour Inventory (HBI), a widely used post-concussive symptom (PCS) rating scale, through factor analyses using bifactor and correlated factor models and by examining measurement invariance (MI). METHODS: PCS ratings were obtained from children aged 8-16.99 years, who presented to the emergency department with concussion (n = 565) or orthopedic injury (OI) (n = 289), and their parents, at 10-days, 3-months, and 6-months post-injury. Item-level HBI ratings were analyzed separately for parents and children using exploratory and confirmatory factor analyses (CFAs). Bifactor and correlated models were compared using various fit indices and tested for MI across time post-injury, raters (parent vs. child), and groups (concussion vs. OI). RESULTS: CFAs showed good fit for both a three-factor bifactor model, consisting of a general factor with two subfactors (i.e., cognitive and somatic), and a correlated two-factor model with cognitive and somatic factors, at all time points for both raters. Some results suggested the possibility of a third factor involving fatigue. All models demonstrated strict invariance across raters and time. Group comparisons showed at least strong or strict invariance. CONCLUSIONS: The findings support the two symptom dimensions measured by the HBI. The three-factor bifactor model showed the best fit, suggesting that ratings on the HBI also can be captured by a general factor. Both correlated and bifactor models showed substantial MI. The results provide further validation of the HBI, supporting its use in childhood concussion research and clinical practice.

Convergent Validity of Myheartsmap: A Pediatric Psychosocial Health Screening Tool.

Recognition of pediatric mental health concerns often depends on assessment by parents, educators, and primary care professionals. Therefore, a psychosocial screening instrument suitable for routine use in schools and primary care is needed. The Pediatric Quality of Life (PedsQL) and the Strengths and Difficulties Questionnaire (SDQ) are widely used for screening but lack adolescent-specific mental health measures. MyHEARTSMAP is an instrument assessing aspects of youth psychosocial health via four domains: Psychiatry, Function, Social, and Youth Health. We evaluated MyHEARTSMAP convergent validity with PedsQL and SDQ among 122 child-parent dyads participating in a larger concussion study. Convergent validity was assessed via correlations: MyHEARTSMAP Psychiatry and Function domains correlated strongly (r ≥ 0.44) and Social domain correlated weakly (r ≤ 0.25) to corresponding PedsQL and SDQ subscales, while Youth Health domain correlated moderately (r ≥ 0.31) to the tools' total scales. In conclusion, MyHEARTSMAP converges with PedsQL and SDQ, and benefits from the inclusion of adolescent-specific psychosocial measures.