Symptom correlates of cerebral blood flow following acute concussion.
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ABSTRACT:
SUBMITTER: Churchill NW
PROVIDER: S-EPMC5545814 | biostudies-literature | 2017
REPOSITORIES: biostudies-literature
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Symptom correlates of cerebral blood flow following acute concussion.
Churchill Nathan W NW Hutchison Michael G MG Graham Simon J SJ Schweizer Tom A TA
NeuroImage. Clinical 20170724
Concussion is associated with significant symptoms within hours to days post-injury, including disturbances in physical function, cognition, sleep and emotion. However, little is known about how subjective impairments correlate with objective measures of cerebrovascular function following brain injury. This study examined the relationship between symptoms and cerebral blood flow (CBF) in individuals following sport-related concussion. Seventy university level athletes had CBF measured using Arte ...[more]
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Project description:ObjectivesThe pathophysiology of sports-related concussion (SRC) is incompletely understood. Human adult and experimental animal investigations have revealed structural axonal injuries, decreases in the neuronal metabolite N-acetyl aspartate, and reduced cerebral blood flow (CBF) after SRC and minor traumatic brain injury. The authors of this investigation explore these possibilities after pediatric SRC.Patients and methodsTwelve children, ages 11 to 15 years, who experienced SRC were evaluated by ImPACT neurocognitive testing, T1 and susceptibility weighted MRI, diffusion tensor imaging, proton magnetic resonance spectroscopy, and phase contrast angiography at <72 hours, 14 days, and 30 days or greater after concussion. A similar number of age- and gender-matched controls were evaluated at a single time point.ResultsImPACT results confirmed statistically significant differences in initial total symptom score and reaction time between the SRC and control groups, resolving by 14 days for total symptom score and 30 days for reaction time. No evidence of structural injury was found on qualitative review of MRI. No decreases in neuronal metabolite N-acetyl aspartate or elevation of lactic acid were detected by proton magnetic resonance spectroscopy. Statistically significant alterations in CBF were documented in the SRC group, with reduction in CBF predominating (38 vs 48 mL/100 g per minute; P = .027). Improvement toward control values occurred in only 27% of the participants at 14 days and 64% at >30 days after SRC.ConclusionsPediatric SRC is primarily a physiologic injury, affecting CBF significantly without evidence of measurable structural, metabolic neuronal or axonal injury. Further study of CBF mechanisms is needed to explain patterns of recovery.
| S-EPMC3255471 | biostudies-literature
Project description:Cognitive enhancements following a single bout of exercise are frequently attributed to increases in cerebral blood flow, however to date we have little understanding of the extent to which such bouts of exercise actually even influence cerebral blood flow following the cessation of exercise. To gain such insight, both regional and global changes in cerebral blood flow were assessed using 3D pseudo-continuous arterial spin-labeled magnetic resonance imaging in a sample of 41 preadolescent children. Using a within-participants randomized crossover design, cerebral blood flow as assessed prior to and following 20-min of either aerobic exercise or an active-control condition during two separate, counterbalanced sessions. The aerobic exercise condition consisted of walking/jogging on a motor driven treadmill at an intensity of approximately 70% of age-predicted maximum heart rate (HR?=?136.1?±?11.1?bpm). The active control condition consisted of walking on the treadmill at the lowest possible intensity (0.5 mph and 0% grade; HR?=?92.0?±?12.2?bpm). Findings revealed no differences in cerebral blood flow following the cessation of exercise relative to the active control condition. These findings demonstrate that cerebral blood flow may not be altered in preadolescent children following the termination of the exercise stimulus during the period when cognitive enhancements have previously been observed.
| S-EPMC6240392 | biostudies-literature
Project description:BackgroundConcussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT's relationship with traditional computerized neurocognitive testing (CNT) domains.MethodsWe employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion, mean ± SD) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05).ResultsConcussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95% confidence interval (95%CI): 70.18-515.54; p = 0.023; d = 0.992). Evasion-RT (p = 0.054; d = 0.806), pedestrian-RT (p = 0.258; d = 0.312), and stoplight-RT (p = 0.292; d = 0.585) outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range: -0.51 to 0.55; p > 0.05). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range: -0.52 to 0.72; p > 0.05).ConclusionSlowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns. Driving-RT and CNT-RT measures correlated moderately but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT.
| S-EPMC7987557 | biostudies-literature
Project description:Symptomatic ischemia following aneurysmal subarachnoid hemorrhage (SAH) is common but poorly understood and inadequately treated. Severe constriction of the major arteries at the base of the brain, termed vasospasm, traditionally has been thought to be a proximal event underlying these ischemias, although microvascular changes also have been described. The vast majority of studies aimed at understanding the pathogenesis of ischemic deficits, and vasospasm have focused on the interaction of the "spasmogen" of the extravasated blood with the smooth muscle and endothelium of the arteries. This has led to a comparative neglect of the contribution of the CNS to the maintenance of cerebral perfusion. In the present study, we focused on the role of the rostral ventromedial medulla (RVM) in modulating cerebral perfusion at rest and following an experimental SAH in the rat. Changes in cerebral blood flow (CBF) were measured using laser-Doppler flowmetry and three-dimensional optical microangiography. Focal application of a GABA(A) receptor agonist and antagonist was used to respectively inactivate and activate the RVM. We show here that the RVM modulates cerebral blood flow under resting conditions, and further, contributes to restoration of cerebral perfusion following a high-grade SAH. Failure of this brainstem compensatory mechanism could be significant for acute perfusion deficits seen in patients following subarachnoid hemorrhage.
| S-EPMC2738929 | biostudies-literature
Project description:Hypoxic hypoxia (inspiratory hypoxia) stimulates an increase in cerebral blood flow (CBF) maintaining oxygen delivery to the brain. However, this response, particularly at the tissue level, is not well characterised. This study quantifies the CBF response to acute hypoxic hypoxia in healthy subjects. A 20-min hypoxic (mean P(ETO2) = 52 mmHg) challenge was induced and controlled by dynamic end-tidal forcing whilst CBF was measured using pulsed arterial spin labelling perfusion MRI. The rate constant, temporal delay and magnitude of the CBF response were characterised using an exponential model for whole-brain and regional grey matter. Grey matter CBF increased from 76.1 mL/100 g/min (95% confidence interval (CI) of fitting: 75.5 mL/100 g/min, 76.7 mL/100 g/min) to 87.8 mL/100 g/min (95% CI: 86.7 mL/100 g/min, 89.6 mL/100 g/min) during hypoxia, and the temporal delay and rate constant for the response to hypoxia were 185 s (95% CI: 132 s, 230 s) and 0.0035 s(-1) (95% CI: 0.0019 s(-1), 0.0046 s(-1)), respectively. Recovery from hypoxia was faster with a delay of 20 s (95% CI: -38 s, 38 s) and a rate constant of 0.0069 s(-1) (95% CI: 0.0020 s(-1), 0.0103 s(-1)). R2*, an index of blood oxygenation obtained simultaneously with the CBF measurement, increased from 30.33 s(-1) (CI: 30.31 s(-1), 30.34 s(-1)) to 31.48 s(-1) (CI: 31.47 s(-1), 31.49 s(-1)) with hypoxia. The delay and rate constant for changes in R2 * were 24 s (95% CI: 21 s, 26 s) and 0.0392 s(-1) (95% CI: 0.0333 s(-1), 0.045 s(-1)), respectively, for the hypoxic response, and 12 s (95% CI: 10 s, 13 s) and 0.0921 s(-1) (95% CI: 0.0744 s(-1), 0.1098 s(-1)/) during the return to normoxia, confirming rapid changes in blood oxygenation with the end-tidal forcing system. CBF and R2* reactivity to hypoxia differed between subjects, but only R2* reactivity to hypoxia differed significantly between brain regions.
| S-EPMC4114548 | biostudies-literature
Project description:Traumatic brain injury (TBI) is associated with increased risk of later-life neurodegeneration and dementia. However, the underpinning mechanisms are poorly understood, and secondary injury resulting from perturbed physiological processes plays a significant role. Cerebral vasoreactivity (CVR), a measure of hemodynamic reserve, is known to be impaired in TBI. However, the temporal course of this physiological perturbation is not established. We examined CVR and clinical symptoms on day 3 (T1), day 21 (T2), and day 90 (T3) after concussion in collegiate athletes and cross-sectionally in non-injured controls. Changes in middle cerebral artery blood flow velocity (MCAV; transcranial Doppler ultrasonography) were measured during changes in end-tidal CO2 (PetCO2) at normocapnia, hypercapnia (inspiring 8% CO2), and hypocapnia (hyperventilation). CVR was determined as the slope of the linear relationship and expressed as percent change in MCAV per mmHg change in PetCO2. CVR was attenuated during the acute phase T1 (1.8?±?0.4U; p?=?0.0001), subacute phases T2 (2.0?±?0.4U; p?=?0.0017), and T3 (1.9?±?0.6U; p?=?0.023) post-concussion compared to the controls (2.3?±?0.3U). Concussed athletes exhibited higher symptom number (2.5?±?3.0 vs. 12.1?±?7.0; p?<?0.0001) and severity (4.2?±?6.0 vs. 29.5?±?23.0; p?<?0.0001), higher Patient Health Questionnaire-9 score (2.2?±?2.0 vs. 9.1?±?6.0; p?=?0.0003) at T1. However, by T2, symptoms had resolved. We show that CVR is impaired as early as 4 days and remains impaired up to 3 months post-injury despite symptom resolution. Persistent perturbations in CVR may therefore be involved in secondary injury. Future studies with a larger sample size and longer follow-up period are needed to validate this finding and delineate the duration of this vulnerable period.
| S-EPMC6909747 | biostudies-literature
Project description:ImportanceDetermining how the timing of return to school is related to later symptom burden is important for early postinjury management recommendations.ObjectiveTo 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 participantsPlanned 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.ExposureThe 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 measuresThe 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.ResultsThis 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 relevanceIn 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.
| S-EPMC9860528 | biostudies-literature
Project description:Concussion is associated with disrupted cerebral blood flow (CBF), although there appears to be substantial inter-individual variability in CBF response. At present, the mechanisms of variable CBF response remain incompletely understood, but one potential contributor is matrix metalloproteinase (MMP) expression. In more severe forms of acquired brain injury, MMP up-regulation contributes to CBF impairments via increased blood-brain barrier permeability. A similar relationship is hypothesized for concussion, where recently concussed individuals with higher MMP levels have lower CBF. To test this hypothesis, 35 concussed athletes were assessed longitudinally at early symptomatic injury (median: 5 days post-injury) and at medical clearance (median: 24 days post-injury), along with 71 athletic controls. For all athletes, plasma MMPs were measured and arterial spin labelling was used to measure CBF. Consistent with our hypothesis, higher concentrations of MMP-2 and MMP-3 were correlated with lower global CBF. The correlations between MMPs and global CBF were also significantly diminished for concussed athletes at medical clearance and for athletic controls. These results indicate an inverse relationship between plasma MMP levels and CBF that is specific to the symptomatic phase of concussion. Analyses of regional CBF further showed that correlations with MMP levels exhibited some spatial specificity, with greatest effects in occipital, parietal and temporal lobes. These findings provide new insights into the mechanisms of post-concussion cerebrovascular dysfunction.
| S-EPMC8562781 | biostudies-literature
Project description:Objective:Motor vehicle collisions generate considerable transmitted forces resulting in traumatic brain injury in children presenting to emergency departments (EDs). To date, no large study has examined post-concussive symptoms in children sustaining concussions in motor vehicle collisions. This study aimed to compare trends in acute post-concussive symptom burden in children with concussion following motor vehicle collisions as compared to other injury mechanisms. Methods:The study is a secondary analysis of the Predicting Persistent Post-concussive Problems in Pediatrics study, which prospectively recruited a multicenter cohort of 3029 children 5-17 years of age presenting to the ED with concussion from 2013-2015. Post-concussive symptom ratings were obtained at pre-specified time points for 12 weeks post-injury, using the validated Post-Concussion Symptom Inventory (PCSI). Symptom severity and recovery trajectories were measured using delta scores on the PCSI (mean post-injury symptom score minus perceived pre-injury score). A multivariable, longitudinal model evaluated the adjusted effect of mechanism of injury (motor vehicle collisions vs other mechanisms) on mean symptom scores, compared to perceived pre-injury reports, and the temporal change in mean scores over during recovery. Results:Of 3029 study participants, 56 (1.8%) sustained concussion from motor vehicle collisions. Children sustaining concussion in a motor vehicle collision had lower post-concussive symptom scores upon ED presentation, measured as differences from their perceived pre-injury reports, as compared to other injury mechanisms (-0.36 [95% confidence interval (CI) = -0.58, -0.15]). However, the motor vehicle collisions group showed the smallest decline in symptom burden over 1 month following injury (-0.54 [95% CI = -0.81, -0.27]). Conclusions:Children sustaining concussions in motor vehicle collisions may have lower initial symptom burdens but slower symptom recovery at 1 month compared to other mechanisms of injury and may represent a distinct population for prognostic counseling in the ED requiring further research.
| S-EPMC7593496 | biostudies-literature
Project description:Objective: To determine the stability of children's retrospective ratings of pre-injury levels of symptoms over time following concussion. Methods: Children and adolescents (n = 3,063) between the ages of 5-17 diagnosed with a concussion by their treating pediatric emergency department (PED) physician within 48 h of injury completed the Post-Concussion Symptom Inventory (PCSI) at the PED and at 1, 2, 4, 8, and 12-weeks post-injury. At each time point, participants retrospectively recalled their pre-injury levels of post-injury symptoms. The PCSI has three age-appropriate versions for children aged 5-7 (PCSI-SR5), 8-12 (PCSI-SR8), and 13-18 (PCSI-SR13). Total scale, subscales (physical, cognitive, emotional, and sleep), and individual items from the PCSI were analyzed for stability using Gini's mean difference (GMD). Results: The mean GMD for total score was 0.31 (95% CI = 0.28, 0.34) for the PCSI-SR5, 0.19 (95% CI = 0.18, 0.20) for the PCSI-SR8, and 0.17 (95% CI = 0.16, 0.18) for the PCSI-SR13. Subscales ranged from mean GMD 0.18 (physical) to 0.31 (emotional) for the PCSI-SR8 and 0.16 (physical) to 0.31 (fatigue) for the PCSI-SR13. At the item-level, mean GMD ranged from 0.13 to 0.60 on the PCSI-SR5, 0.08 to 0.59 on the PCSI-SR8, and 0.11 to 0.41 on the PCSI-SR13. Conclusions: Children and adolescents recall their retrospective pre-injury symptom ratings with good-to-perfect stability over the first 3-months following their concussion. Although some individual items underperformed, variability was reduced as items were combined at the subscale and full-scale level. There is limited benefit gained from collecting multiple pre-injury symptom queries. Clinical Trial Registration: Clinicaltrials.gov through the US National Institute of Health/National Library of Medicine. (NCT01873287; http://clinicaltrials.gov/ct2/show/NCT01873287).
| S-EPMC6610489 | biostudies-literature