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OBJECTIVE: Posttraumatic headache (PTH) represents the most common acute and persistent postconcussive symptom (PCS) in children after concussion, yet there remains a lack of valid and objective biomarkers to facilitate risk stratification and early intervention in this patient population. Fixel-based analysis of diffusion-weighted imaging, which overcomes constraints of traditional diffusion tensor imaging analyses, can improve the sensitivity and specificity of detecting white matter changes postconcussion. The aim of this study was to investigate whole-brain and tract-based differences in white matter morphology, including fiber density (FD) and fiber bundle cross-section (FC) area in children with PCSs and PTH at 2 weeks after concussion. METHODS: This prospective longitudinal study recruited children aged 5-18 years who presented to the emergency department of a tertiary pediatric hospital with a concussion sustained within the previous 48 hours. Participants underwent diffusion-weighted MRI at 2 weeks postinjury. Whole-brain white matter statistical analysis was performed at the level of each individual fiber population within an image voxel (fixel) to compute FD, FC, and a combined metric (FD and bundle cross-section [FDC]) using connectivity-based fixel enhancement. Tract-based Bayesian analysis was performed to examine FD in 23 major white matter tracts. RESULTS: Comparisons of 1) recovered (n = 27) and symptomatic (n = 16) children, and those with 2) PTH (n = 13) and non-PTH (n = 30; overall mean age 12.99 ± 2.70 years, 74% male) found no fiber-specific white matter microstructural differences in FD, FC, or FDC at 2 weeks postconcussion, when adjusting for age and sex (family-wise error rate corrected p value > 0.05). Tract-based Bayesian analysis showed evidence of no effect of PTH on FD in 10 major white matter tracts, and evidence of no effect of recovery group on FD in 3 white matter tracts (Bayes factor < 1/3). CONCLUSIONS: Using whole-brain fixel-wise and tract-based analyses, these findings indicate that fiber-specific properties of white matter microstructure are not different between children with persisting PCSs compared with recovered children 2 weeks after concussion. These data extend the limited research on white matter fiber-specific morphology while overcoming limitations inherent to traditional diffusion models. Further validation of our findings with a large-scale cohort is warranted.

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OBJECTIVE: To identify differential trajectories of neurocognitive outcomes following pediatric concussion and investigate predictors associated with patterns of recovery up to 3 months. METHODS: 74 participants aged 8-17 years completed attention/working memory, processing speed, and executive function measures at 2 weeks, 1 month, and 3 months post-injury. We used principal component analysis to generate a composite of information processing. Group-based trajectory modeling identified latent trajectories. Multinominal logistic regression was used to examine associations between risk factors and trajectory groups. RESULTS: We identified three trajectories of neurocognitive outcomes. The medium (54.6%) and high improving groups (35.8%) showed ongoing increase in information processing, while the low persistent group showed limited change 3 months post-injury. This group recorded below average scores on Digit Span Forward and Backward at 3 months. History of pre-injury headache was significantly associated with the persistent low scoring group, relative to the medium improving (p = 0.03) but not the high improving group (p = 0.09). CONCLUSIONS: This study indicates variability in neurocognitive outcomes according to three differential trajectories, with groups partially distinguished by preexisting child factors (history of frequent headaches). Modelling that accounts for heterogeneity in individual outcomes is essential to identify clinically meaningful indices that are indicative of children requiring intervention.

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BACKGROUND: Neurofilament light (NfL) has previously been highlighted as a potential biomarker for Huntington's Disease (HD) using cross-sectional analyses. Our study aim was to investigate how longitudinal trajectories of plasma NfL relate to HD disease stage. METHODS: 108 participants [78 individuals with the HD mutation, and 30 healthy controls (HC)] were included in this study. Individuals with the HD mutation were categorised separately by both HD-Integrated Staging System (HD-ISS) (Study 1) and PIN score-Approximated Staging System (PASS) (Study 2) criteria. Plasma NfL trajectories were examined using Mixed Linear Modeling (MLM); associations with symptom presentation were assessed using Spearman's rho correlations. FINDINGS: The MLM coefficients for disease stage (HD-ISS ß = 32.73, p < 0.0001; PASS ß = 33.00, p < 0.0001) and disease stage∗time (HD-ISS ß = 7.85, p = 0.004; PASS ß = 6.58, p = 0.0047) suggest these are significant contributors to plasma NfL levels. In addition, the plasma NfL rate of change varied significantly across time (HD-ISS ß = 3.14, p = 0.04; PASS ß = 2.94, p = 0.050). The annualised rate of change was 8.32% for HC; 10.55%, 12.75% and 15.62% for HD-ISS Stage ≤1, Stage 2, and Stage 3, respectively; and 12.13%, 10.46%, 10.33%, 17.52%, for PASS Stage 0, Stage 1, Stage 2, and Stage 3, respectively. Plasma NfL levels correlated with the Symbol Digit Modalities Test (SDMT) in HD-ISS Stage ≤1, and both SDMT and Total Motor Score in Stage 3 (ps < 0.01). INTERPRETATION: Our findings suggest that plasma NfL levels increase linearly across earlier disease stages, correlating with the cognitive SDMT measure. Thereafter, an increase or surge in plasma NfL levels, paired with correlations with both cognitive and motor measures, suggest a late acceleration in clinical and pathological progression. FUNDING: NIH (NS111655); the UCSD HDSA CoE; the UCSD ADRC (NIH-NIA P30 AG062429).

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Of the four million children who experience a concussion each year, 30-50% of children will experience delayed recovery, where they will continue to experience symptoms more than two weeks after their injury. Delayed recovery from concussion encompasses emotional, behavioral, physical, and cognitive symptoms, and as such, there is an increased focus on developing an objective tool to determine risk of delayed recovery. This study aimed to identify a blood protein signature predictive of delayed recovery from concussion in children. Plasma samples were collected from children who presented to the Emergency Department at the Royal Children's Hospital, Melbourne, within 48h post-concussion. This study involved a discovery and validation phase. For the discovery phase, untargeted proteomics analysis was performed using single window acquisition of all theoretical mass spectra to identify blood proteins differentially abundant in samples from children with and without delayed recovery from concussion. A subset of these proteins was then validated in a separate participant cohort using multiple reaction monitoring and enzyme linked immunosorbent assay. A blood protein signature predictive of delayed recovery from concussion was modeled using a Support Vector Machine, a machine learning approach. In the discovery phase, 22 blood proteins were differentially abundant in age- and sex-matched samples from children with (n = 9) and without (n = 9) delayed recovery from concussion, six of whom were chosen for validation. In the validation phase, alpha-1-ACT was shown to be significantly lower in children with delayed recovery (n = 12) compared with those without delayed recovery (n = 28), those with orthopedic injuries (n = 7) and healthy controls (n = 33). A model consisting of alpha-1-ACT concentration stratified children based on recovery from concussion with an 0.88 area under the curve. We have identified that alpha-1-ACT differentiates between children at risk of delayed recovery from those without delayed recovery from concussion. To our knowledge, this is the first study to identify alpha-1-ACT as a potential marker of delayed recovery from concussion in children. Multi-site studies are required to further validate this finding before use in a clinical setting.

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Background: Bradyphrenia, best thought of as the mental equivalent of bradykinesia, has been described in several disorders of the brain including Parkinson's disease and schizophrenia; however, little is known about this phenomenon in Huntington's Disease (HD). Objective: The aim of this study was to investigate the presence of bradyphrenia in HD using the Computerized Test of Information Processing (CTiP), an easy to administer and objective task that assesses cognitive processing speed with increasing task complexity. Methods: This study included 211 participants: Huntington's Disease Integrated Staging System (HD-ISS) Stage 0 [n = 28], Stage 1 [n = 30], Stage 2 [n = 48] and Stage 3 [n = 48], and healthy controls (HC) [n = 57]. The CTiP incorporates three subtests: Simple Reaction Time (SRT), which assesses baseline motor function; Choice Reaction Time (CRT), with an added decisional component; and Semantic Search Reaction Time (SSRT), with an added conceptual component. SRT scores were subtracted from CRT and SSRT scores to establish a motor-corrected measure of central conduction time, which was used to operationalize bradyphrenia. Results: HD-ISS and HC within-group reaction times differed significantly when comparing motor-corrected CRT vs SSRT (all ps < 0.0001). Furthermore, the magnitude of these differences increased with HD disease stage (p < 0.0001). An ROC analysis determined that motor-corrected within-subject differences significantly distinguished Stage 2 + 3 from Stage 0 + 1 (AUC = 0.72, p < 0.0001). Conclusions: We report evidence of bradyphrenia in HD that increases with disease progression. This processing deficit, which can be quantified using the CTiP, has the potential to greatly impact HD daily life and warrants additional research.

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OBJECTIVE: Posttraumatic headache (PTH) represents the most common acute and persistent symptom in children after concussion, yet there is no blood protein signature to stratify the risk of PTH after concussion to facilitate early intervention. This discovery study aimed to identify capillary blood protein markers, at emergency department (ED) presentation within 48 hours of concussion, to predict children at risk of persisting PTH at 2 weeks postinjury. METHODS: Capillary blood was collected using the Mitra Clamshell device from children aged 8-17 years who presented to the ED of the Royal Children's Hospital, Melbourne, Australia, within 48 hours of sustaining a concussion. Participants were followed up at 2 weeks postinjury to determine PTH status. PTH was defined per clinical guidelines as a new or worsened headache compared with preinjury. An untargeted proteomics analysis using data-independent acquisition (DIA) was performed. Principal component analysis and hierarchical clustering were used to reduce the dimensionality of the protein dataset. RESULTS: A total of 907 proteins were reproducibly identified from 82 children within 48 hours of concussion. The mean participant age was 12.78 years (SD 2.54 years, range 8-17 years); 70% of patients were male. Eighty percent met criteria for acute PTH in the ED, while one-third of participants with follow-up experienced PTH at 2 weeks postinjury (range 8-16 days). Hemoglobin subunit zeta (HBZ), cystatin B (CSTB), beta-ala-his dipeptidase (CNDP1), hemoglobin subunit gamma-1 (HBG1), and zyxin (ZYX) were weakly associated with PTH at 2 weeks postinjury based on up to a 7% increase in the PTH group despite nonsignificant Benjamini-Hochberg adjusted p values. CONCLUSIONS: This discovery study determined that no capillary blood protein markers, measured at ED presentation within 48 hours of concussion, can predict children at risk of persisting PTH at 2 weeks postinjury. While HBZ, CSTB, CNDP1, HBG1, and ZYX were weakly associated with PTH at 2 weeks postinjury, there was no specific blood protein signature predictor of PTH in children after concussion. There is an urgent need to discover new blood biomarkers associated with PTH to facilitate risk stratification and improve clinical management of pediatric concussion.

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BACKGROUND: The recently proposed Huntington's Disease Integrated Staging System (HD-ISS) categorises individuals with the Huntintin genetic mutation into disease progression cohorts based on quantitative neuroimaging, cognitive, and functional markers for research purposes. Unfortunately, many research studies do not collect quantitative neuroimaging data, and so the authors of the HD-ISS have subsequently provided approximated cohort thresholds based on disease and clinical data alone. However, these are rough proxies that aim to maximise stage separation, and should not be considered as 1:1 substitutes for the HD-ISS. Notably, no wet biomarker met the stringent criteria required to be considered a landmark for HD-ISS categorisation. We have previously shown that levels of plasma neurofilament light (NfL), a neuronal marker associated with axonal injury, are associated with predicted years to clinical motor diagnosis (CMD). Our objective in the current study was to determine whether HD-ISS categorisation, particularly for stages prior to CMD, could be improved with consideration of plasma NfL levels. METHODS: A total of 290 blood samples, and clinical measures, were collected from participants across all HD-ISS stages: n = 50 [Stage 0], n = 64 [Stage 1], n = 63 [Stage 2], n = 63 [Stage 3], as well as 50 healthy controls. Plasma NfL levels were measured using a Meso Scale Discovery assay. FINDINGS: Cohorts differed by age, cognitive function, CAG repeat length, and select UHDRS measures. Plasma NfL levels also differed significantly across cohorts. Approximately 50% of Stage 1 participants had plasma NfL levels indicative of predicted CMD within ten years. INTERPRETATION: Our findings suggest that plasma NfL levels may have use in enriching Stage 1 membership into sub-groups that are less than, and within, predicted 10 years until CMD. FUNDING: This work was supported by the National Institutes of Health (NS111655 to E.A.T.); the UCSD Huntington's Disease Society of America Center of Excellence; and the UCSD Shiley-Marcos Alzheimer's Disease Research Center (NIH-NIA P30 AG062429).

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OBJECTIVE: Persisting postconcussive symptoms (pPCS), particularly headache, can significantly disrupt children's recovery and functioning. However, the underlying pathophysiology of these symptoms remains unclear. The goal in this study was to determine whether pPCS are related to cerebral blood flow (CBF) at 2 weeks postconcussion. The authors also investigated whether variations in CBF can explain the increased risk of acute posttraumatic headache (PTH) in female children following concussion. METHODS: As part of a prospective, longitudinal study, the authors recruited children 5-18 years old who were admitted to the emergency department of a tertiary pediatric hospital with a concussion sustained within 48 hours of admission. Participants underwent pseudocontinuous arterial spin labeling MRI at 2 weeks postconcussion to quantify global mean gray and white matter perfusion (in ml/100 g/min). Conventional frequentist analysis and Bayesian analysis were performed. RESULTS: Comparison of recovered (n = 26) and symptomatic (n = 12) groups (mean age 13.15 years, SD 2.69 years; 28 male) found no differences in mean global gray and white matter perfusion at 2 weeks postconcussion (Bayes factors > 3). Although female sex was identified as a risk factor for PTH with migraine features (p = 0.003), there was no difference in CBF between female children with and without PTH. CONCLUSIONS: Global CBF was not associated with pPCS and female PTH at 2 weeks after pediatric concussion. These findings provide evidence against the use of CBF measured by arterial spin labeling as an acute biomarker for pediatric concussion recovery.

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BACKGROUND: Lithium medication is considered to be the first-line treatment for bipolar disorder as a monotherapy, and for treatment-resistant depression with lithium augmentation. However, because of potential toxicity, lithium levels must be monitored frequently. Recent studies have demonstrated a significant correlation between lithium levels measured in serum and those detected in oral fluid, suggesting that oral fluid analysis may represent an easy, noninvasive means to monitor lithium levels. The aim of this study was to evaluate the analytical performance of rapid assays for lithium measurements in oral fluid. METHODS: Levels of lithium in oral fluid from psychiatric patients (n = 108 in total) taking lithium medications were quantified using 2 rapid techniques: an automated clinical chemistry analyzer and a novel, commercially available colorimetric lithium assay. These results were compared with those obtained using inductively coupled plasma optical emission spectrometry (ICP-OES). RESULTS: The mean and median oral fluid lithium levels in this cohort were 1.43-1.61 mM and 1.32-1.52 mM, respectively, depending on the method, with the overall range, across all methods, being 0.213-4.42 mM. Linear regression analysis showed excellent agreement between the oral fluid values measured using ICP-OES and the colorimetric method (r 2 value = 0.926; P < 0.0001; slope = 1.084 ± 0.038). Similarly, excellent agreement was observed between ICP-OES and the automated method (r 2 = 0.872; P < 0.0001; slope = 1.019 ± 0.057). CONCLUSIONS: These results demonstrate that lithium levels in oral fluid can be rapidly and reliably quantified using colorimetric approaches. These findings may facilitate the development of point-of-care lithium monitoring systems for use in oral fluid.

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Measuring Huntingtin (HTT) protein in peripheral cells represents an essential step in biomarker discovery for Huntington's Disease (HD), however to date, investigations into the salivary expression of HTT has been lacking. In the current study, we quantified total HTT (tHTT) and mutant HTT (mHTT) protein in matched blood and saliva samples using single molecule counting (SMC) immunoassays: 2B7-D7F7 (tHTT) and 2B7-MW1 (mHTT). Matched samples, and clinical data, were collected from 95 subjects: n = 19 manifest HD, n = 34 premanifest HD (PM), and n = 42 normal controls (NC). Total HTT and mHTT levels were not correlated in blood and saliva. Plasma tHTT was significantly associated with age, and participant sex; whereas salivary mHTT was significantly correlated with age, CAG repeat length and CAP score. Plasma and salivary tHTT did not differ across cohorts. Salivary and plasma mHTT were significantly increased in PM compared to NC; salivary mHTT was also significantly increased in HD compared to NC. Only salivary tHTT and mHTT were significantly correlated with clinical measures. Salivary HTT is uniquely associated with clinical measures of HD and offers significant promise as a relevant, non-invasive HD biomarker. Its use could be immediately implemented into both translational and clinical research applications.

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BACKGROUND: Inflammatory responses play key roles in the development and progression of many pathological conditions, including neurodegenerative diseases. Accurate quantification of inflammatory factors in saliva would be highly advantageous, given its convenience and non-invasive nature, especially in elderly populations. METHODS: In this study, we measured levels of 10 cytokines, and the pro-inflammatory factor, YKL-40, in plasma and saliva samples from a cohort of nondemented older adults (n = 71; 62% female; 70.3 ± 6.4 years) using sensitive electrochemiluminescence-based immunoassays. RESULTS: We found that the mean levels of all cytokines were higher in saliva compared to plasma and that strong sex differences were observed for both saliva and plasma cytokines in this population. Comparing each cytokine between the two biofluids, we found that levels of interferon-gamma (IFNγ), interleukin (IL)-6 and tumor necrosis factor-alpha (TNFα) in blood were significantly correlated with their respective levels in saliva. We further observed that levels of these cytokines in blood were significantly correlated with additional cytokines in saliva, including IL-1ß, IL-10, IL-8, IL12p70 and IL-13. CONCLUSIONS: These findings show that inflammatory markers in saliva are associated with those found in circulation, suggesting shared inflammatory mechanisms between these two fluids. The higher levels of cytokines measured in saliva suggest that it might represent a better peripheral fluid to gauge inflammatory processes. Finally, our findings of robust sex differences in several salivary cytokines could have important implications for their potential use as disease biomarkers in the elderly and might be related to sex differences in the prevalence of age-related conditions.

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Purpose: Despite lithium being a gold standard treatment for bipolar disorder, the percentage of patients with bipolar disorder who are prescribed lithium medication has declined in many parts of the world over the past two decades. The use of lithium is limited by its narrow therapeutic window and adverse side effects, which necessitates frequent serum lithium monitoring; hence, there is a critical need for improved ways to monitor lithium levels in psychiatric patients. We have recently shown that saliva lithium levels are highly correlated with those in blood, thereby presenting an alternative to venipuncture. Saliva sampling could open the door for at-home collections - potential that has been exemplified throughout the COVID-19 pandemic - thereby allowing samples to be collected remotely and delivered to a specific site for testing. In addition, prototype point-of-care devices have been developed by others for serum lithium monitoring, suggesting potential for a saliva lithium monitoring device. Our objective was to query the perspectives of American psychiatrists on lithium treatment practices and obstacles, the potential for at-home saliva collection and point-of-care devices, for lithium monitoring, as an alternative to pathology-based blood testing. Methods: Data was collected through an online, anonymous survey, distributed to American psychiatric societies. Results: Sixty-five respondents from 21 American states completed the survey. The majority of respondents were female, over 65 years of age, and/or had practiced for 30 years or more. The most frequent obstacles encountered with regard to lithium monitoring were adverse drug effects, and the need for monitoring. Overall, respondents believed saliva lithium monitoring and point-of-care devices would be useful, however raised concerns regarding validity and time-delay. Conclusion: Point-of-care devices and saliva lithium monitoring are promising alternatives to blood testing that would be welcomed by psychiatric societies, however, require extensive development and validation before implementation into a clinical setting.

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INTRODUCTION: The inclusion of premanifest Huntington's Disease (Pre-HD) subjects in clinical trials necessitates selecting those who are near transition to manifest Huntington's disease (Man-HD). We previously determined that plasma neurofilament light (NfL) levels are significantly correlated with predicted years to Man-HD onset, using established formulae. Recently, a new normalized prognostic index (PIN) score for predicting Pre-HD disease progression has been validated. Our objective was to determine whether plasma NfL levels are similarly associated with PIN score and PIN score-derived years to Man-HD onset (PIN-YTO). METHOD: 112 individuals (46 Pre-HD, 66 Man-HD) underwent blood sample collection and clinical assessment, inclusive of the Symbol Digit Modalities Test and Unified Huntington's Disease Rating Scale Total Motor Score. Plasma NfL levels were measured using a Meso Scale Discovery assay. RESULTS: Pre-HD and Man-HD cohorts differed by age (p < .0001), and CAG repeat number (p = .004), but not education level or gender. Plasma NfL levels were significantly correlated with PIN scores (r = 0.69, p < .0001) and PIN-YTO (r = -0.69, p < .0001). Plasma NfL levels were similarly correlated with predicted years to onset scores determined using Langbehn and colleague's formula (r = -0.68, p < .0001). All significant correlations endured corrections for age and CAG repeat number. A plasma NfL cut-point of <45.0 pg/ml distinguished Pre-HD participants >10 predicted years from Man-HD onset, compared to those ≤10 predicted years. CONCLUSIONS: We have extensively shown that plasma NfL levels are associated with predicted years to manifest HD onset in Pre-HD participants, and present a plasma NfL cut-point that may help exclude far-from-onset Pre-HD patients from clinical trials.

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The Sports Concussion Assessment Tool-5th Edition (SCAT5) and the child version (Child SCAT5) are the current editions of the SCAT and have updated the memory testing component from previous editions. This study aimed to validate this new memory component against the Rey Auditory Verbal Learning Test (RAVLT) as the validated standard. This prospective, observational study, carried out within The Royal Children's Hospital Emergency Department, Melbourne, Australia, recruited 198 participants: 91 with concussion and 107 upper limb injury or healthy sibling controls. Partial Pearson correlations showed that memory acquisition and recall on delay aspects of the SCAT5 were significantly correlated with the RAVLT equivalents when controlling for age (p < 0.001, r = 0.565 and p < 0.001, r = 0.341, respectively). Factor analysis showed that all RAVLT and SCAT5 memory components load on to the same factor, accounting for 59.13% of variance. Logistic regression models for both the RAVLT and SCAT5, however, did not predict group membership (p > 0.05). Receiver operating curve analysis found that the area under the curve for all variables and models was below the recommended 0.7 threshold. This study demonstrated that the SCAT5 and Child SCAT5 memory paradigm is a valid measure of memory in concussed children.

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The Sport Concussion Assessment Tool 5th Edition (SCAT5) is a standardized measure of concussion. In this prospective observational study, the ability of the SCAT5 and ChildSCAT5 to differentiate between children with and without a concussion was examined. Concussed children (n=91) and controls (n=106) were recruited from an emergency department in three equal-sized age bands (5-8/9-12/13-16 years). Analysis of covariance models (adjusting for participant age) were used to analyze group differences on components of the SCAT5. On the SCAT5 and ChildSCAT5, respectively, youth with concussion reported a greater number (d=1.47; d=0.52) and severity (d=1.27; d=0.72) of symptoms than controls (all p<0.001). ChildSCAT5 parent-rated number (d=0.98) and severity (d=1.04) of symptoms were greater for the concussion group (all p<0.001). Acceptable levels of between-group discrimination were identified for SCAT5 symptom number (AUC=0.86) and severity (AUC=0.84) and ChildSCAT5 parent-rated symptom number (AUC=0.76) and severity (AUC=0.78). Our findings support the utility of the SCAT5 and ChildSCAT5 to accurately distinguish between children with and without a concussion.

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OBJECTIVE: The narrow therapeutic window of lithium medications necessitates frequent serum monitoring, which can be expensive and inconvenient for the patient. Compared to blood, saliva collection is easier, non-invasive, requires less processing, and can be done without the need for trained personnel. This study investigated the utility of longitudinal salivary lithium level monitoring. METHODS: We measured salivary lithium levels using ICP-OES in n = 169 passive drool samples, collected both as single observations and longitudinally for up to 18 months, from a multi-center cohort of n = 75 patients with bipolar disorder or other psychiatric conditions. RESULTS: Saliva and serum lithium levels were highly correlated. Adjustment for daily lithium dose, diabetes, and smoking improved this relationship (r = 0.77). Using the adjusted intersubject equation and a patient's salivary lithium value, we observed a strong correlation between the predicted vs. observed serum lithium levels (r = 0.70). Most patients had highly stable saliva/serum ratios across multiple visits, with longitudinal variability significantly greater with age. Use of the intrasubject saliva/serum ratio from a single prior observation had similar predictive power to the use of the adjusted intersubject equation. However, the use of the mean intrasubject ratio from three prior observations could robustly predict serum lithium levels (predicted vs. observed r = 0.90). CONCLUSIONS: These findings strongly suggest that saliva could be used for lithium monitoring, and open the door for the development and implementation of a point-of-care salivary lithium device for use at home or the clinic. We propose that the use of saliva will dramatically improve treatment opportunities for patients with mood disorders.

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OBJECTIVE: To investigate whether plasma NfL levels correlate with clinical symptom severity in premanifest (PM) and manifest HD (HD) individuals, and whether a NfL cut-point could distinguish PM from HD patients with reasonable accuracy. METHOD: 98 participants (33 control, 26 PM, 39 HD), underwent blood sample collection and clinical assessment, using both UHDRS and non-UHDRS measures, at one academic HD Center. Years to onset (YTO), probability of disease onset in 5 years, and predicted years until 60% onset probability were also calculated. NfL levels were measured using a Meso Scale Discovery assay. RESULTS: Cohorts differed by age. NfL levels differed significantly across diagnostic groups and were significantly correlated with age. Age-adjusted NfL levels were not correlated with clinical measures in either HD or PM cohorts, but were correlated when cohorts were combined. In PM subjects, NfL levels correlated with YTO, probability of onset in 5 years, and years until 60% onset probability. Using ROC analysis, a NfL cut-point of <53.15 pg/ml distinguished HD from control; <74.84 pg/ml distinguished HD from PM. CONCLUSIONS: These findings implicate plasma NfL as a peripheral prognostic marker for premanifest-HD. Notably, we show that significant correlations between NfL and clinical symptoms are detected only when PM + HD subjects are combined, but not within HD subjects alone. To date, prior studies have investigated the clinical usefulness of NfL exclusively in merged PM + HD cohorts. Our data suggests a biasing of these previous correlations, and hence potentially limited usefulness of plasma NfL in monitoring HD symptom progression, for example, in clinical trials.

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INTRODUCTION: While most children recover from a concussion shortly after injury, approximately 30% experience persistent postconcussive symptoms (pPCS) beyond 1-month postinjury. Existing research into the treatment of pPCS have evaluated unimodal approaches, despite evidence suggesting that pPCS likely represent an interaction across various symptom clusters. The primary aim of this study is to evaluate the effectiveness of a multimodal, symptom-tailored intervention to accelerate symptom recovery and increase the proportion of children with resolved symptoms at 3 months postconcussion. METHODS AND ANALYSIS: In this open-label, assessor-blinded, randomised clinical trial, children with concussion aged 8-18 years will be recruited from The Royal Children's Hospital (The RCH) emergency department, or referred by a clinician, within 17 days of initial injury. Based on parent ratings of their child's PCS at ~10 days postinjury, symptomatic children (≥2 symptoms at least 1-point above those endorsed preinjury) will undergo a baseline assessment at 3 weeks postinjury and randomised into either Concussion Essentials (CE, n=108), a multimodal, interdisciplinary delivered, symptom-tailored treatment involving physiotherapy, psychology and education, or usual care (UC, n=108) study arms. CE participants will receive 1 hour of intervention each week, for up to 8 weeks or until pPCS resolve. A postprogramme assessment will be conducted at 3 months postinjury for all participants. Effectiveness of the CE intervention will be determined by the proportion of participants for whom pPCS have resolved at the postprogramme assessment (primary outcome) relative to the UC group. Secondary outcome analyses will examine whether children receiving CE are more likely to demonstrate resolution of pPCS, earlier return to normal activity, higher quality of life and a lower rate of utilisation of health services, compared with the UC group. ETHICS AND DISSEMINATION: Ethics were approved by The RCH Human Research Ethics Committee (HREC: 37100). Parent, and for mature minors, participant consent, will be obtained prior to commencement of the trial. Study results will be disseminated at international conferences and international peer-reviewed journals. TRIAL REGISTRATION NUMBER: ACTRN12617000418370; pre-results.

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Neuroimaging is being increasingly applied to the study of paediatric mild traumatic brain injury (mTBI) to uncover the neurobiological correlates of delayed recovery post-injury. The aims of this systematic review were to: (i) evaluate the neuroimaging research investigating neuropathology post-mTBI in children and adolescents from 0-18 years, (ii) assess the relationship between advanced neuroimaging abnormalities and PCS in children, (iii) assess the quality of the evidence by evaluating study methodology and reporting against best practice guidelines, and (iv) provide directions for future research. A literature search of MEDLINE, PsycINFO, EMBASE, and PubMed was conducted. Abstracts and titles were screened, followed by full review of remaining articles where specific eligibility criteria were applied. This systematic review identified 58 imaging studies which met criteria. Based on several factors including methodological heterogeneity and relatively small sample sizes, the literature currently provides insufficient evidence to draw meaningful conclusions about the relationship between MRI findings and clinical outcomes. Future research is needed which incorporates prospective, longitudinal designs, minimises potential confounds and utilises multimodal imaging techniques.

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In this paper we outline and compare pharmaceutical pricing policies for in-patent prescription pharmaceuticals with emphasis on external reference pricing (ERP) in eleven countries across the Middle East and North Africa (MENA) region and explore possible improvements in their pricing systems. Primary and secondary evidence was used to inform our analysis. Comparative analysis of ERP systems across countries followed an analytical framework distilling ERP into twelve salient features, while ERP system performance was benchmarked against a framework of best practice principles across (a) objectives and scope, (b) administration and operations, (c) methods used, and (d) implementation. Results suggest that ERP is the dominant pricing method for in-patent pharmaceuticals. Although several good practice cases were identified, none of the eleven countries satisfy all best practice principles. ERP basket sizes vary significantly and are commonly composed using geographical proximity and low-price countries as criteria. Nine countries do not use the mean or median prices, but resort to using the lowest. Exchange rate fluctuations are routinely used to arrive at price reductions in local currency. Significant opportunities exist for MENA countries to develop their ERP regimes to achieve greater compliance with best practice principles. Over the short-term, incremental changes could be implemented to several ERP salient features and can be achieved relatively easily, thereby enhancing the functionality and performance of national ERP systems. Countries in the region can also focus on the development of explicit value assessment systems, and minimize their dependence on ERP over the longer-term.

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