Cerebral blood flow in children and adolescents several years after concussion

Brooks, Brian L.; Low, Trevor A.; Plourde, Vickie; Virani, Shane; Jadavji, Zeanna; MacMaster, Frank P.; Barlow, Karen M.; Lebel, R. Marc; Yeates, Keith Owen

doi:10.1080/02699052.2018.1540798

Cited by 24 publications

(23 citation statements)

References 37 publications

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“…Our data suggest that a concussion may result in alterations in cerebrovascular regulatory mechanisms, which, in turn, helps explain the variability in resting cerebral blood flow velocity reported in prior work. [13][14][15][16][17] Our results also show that these changes (1) relate to acute (within 2 weeks of injury) post-concussion symptom burden, (2) persist chronically (8-week post-injury) despite symptom resolution, and (3) may be favorably modified by aerobic exercise. These results mechanistically support the current notion of the relationship between physiologic impact of concussion and concussion symptomatology.…”

Section: Discussionsupporting

confidence: 62%

“…On one hand, prior research has shown that a concussion could indeed trigger pathophysiologic alterations in cerebral blood flow among pediatric patients. 33 On the other hand, these alterations may result in reduced, 13,14 similar, 15,16 or increased 17 global and regional cerebral blood flow. Our observations provide a simple explanation for this discrepancy.…”

Section: Discussionmentioning

confidence: 99%

“…However, data from both animals 4,10,11 and humans 12 suggest that cerebral blood flow may decrease after a concussion and can remain reduced for extended periods of time, resulting in an 'energy mismatch,' or neurometabolic crisis. 4 While this seems reasonable, available data is conflicting: global and regional cerebral blood flow can be reduced, 13,14 unchanged, 15,16 or even increased 17 in individuals who have suffered a concussion, and these changes may or may not relate to symptom burden. 18 While part of this discrepancy may be due to methodological differences between the studies, it also highlights the possibility that concussion impacts the regulation of cerebral blood flow to meet metabolic demand, and not the resting blood flow per se.…”

mentioning

confidence: 99%

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Cerebrovascular Neuroprotection after Acute Concussion in Adolescents

Aaron

Hamner

Ozturk

et al. 2021

Annals of Neurology

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Objective: To assess acute cerebrovascular function in concussed adolescents (14-21 years of age), whether it is related to resting cerebral hemodynamics, and whether it recovers chronically. Methods: Cerebral vasoreactivity and autoregulation, based on middle cerebral artery blood flow velocity, was assessed in 28 concussed participants (≤14 days of injury) and 29 matched controls. The participants in the concussion group returned for an 8-week follow-up assessment. Over the course of those 8-weeks, participants recorded aerobic exercise frequency and duration. Results: Between groups, demographic, clinical, and hemodynamic variables were not significantly different. Vasoreactivity was significantly higher in the concussed group (p = 0.02). Within the concussed group, 60% of the variability in resting cerebral blood flow velocity was explained by vasoreactivity and two components of autoregulationfalling slope and effectiveness of autoregulation (adjusted R 2 = 0.60, p < 0.001). Moreover, lower mean arterial pressure, lower responses to increases in arterial pressure, and lower vasoreactivity were significantly associated with larger symptom burden (adjusted R 2 = 0.72, p < 0.01). By the 8-week timepoint, symptom burden, but not vasoreactivity, improved in all but four concussed participants (p < 0.01). 8-week change in vasoreactivity was positively associated with aerobic exercise volume (adjusted R 2 = 0.19, p = 0.02). Interpretation: Concussion resulted in changes in cerebrovascular regulatory mechanisms, which in turn explained the variability in resting cerebral blood flow velocity and acute symptom burden. Furthermore, these alterations persisted chronically despite symptom resolution, but was positively modified by aerobic exercise volume. These findings provide a mechanistic framework for further investigation into underlying cerebrovascular related symptomatology.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Cerebrovascular Neuroprotection after Acute Concussion in Adolescents

Aaron

Hamner

Ozturk

et al. 2021

Annals of Neurology

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“…This group also used resting and task-based ASL sequences to detect occipital and temporal hypoperfusion in 2012 in a cohort of 21 moderate-severe TBI patients (27). CBF remains abnormal into the chronic phase (28)(29)(30)(31)(32), and has been associated cognitive performance (27), symptom severity (32) and recovery (30).…”

Section: Introductionmentioning

confidence: 99%

Cerebral Perfusion Effects of Cognitive Training and Transcranial Direct Current Stimulation in Mild-Moderate TBI

et al. 2020

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Background: Persistent post-traumatic symptoms (PPS) after traumatic brain injury (TBI) can lead to significant chronic functional impairment. Pseudocontinuous arterial spin labeling (pCASL) has been used in multiple studies to explore changes in cerebral blood flow (CBF) that may result in acute and chronic TBI, and is a promising neuroimaging modality for assessing response to therapies. Methods: Twenty-four subjects with chronic mild-moderate TBI (mmTBI) were enrolled in a pilot study of 10 days of computerized executive function training combined with active or sham anodal transcranial direct current stimulation (tDCS) for treatment of cognitive PPS. Behavioral surveys, neuropsychological testing, and magnetic resonance imaging (MRI) with pCASL sequences to assess global and regional CBF were obtained before and after the training protocol. Results: Robust improvements in depression, anxiety, complex attention, and executive function were seen in both active and sham groups between the baseline and post-treatment visits. Global CBF decreased over time, with differences in regional CBF noted in the right inferior frontal gyrus (IFG). Active stimulation was associated with static or increased CBF in the right IFG, whereas sham was associated with reduced CBF. Neuropsychological performance and behavioral symptoms were not associated with changes in CBF. Discussion: The current study suggests a complex picture between mmTBI, cerebral perfusion, and recovery. Changes in CBF may result from physiologic effect of the intervention, compensatory neural mechanisms, or confounding factors. Limitations include a small sample size and heterogenous injury sample, but these findings suggest promising directions for future studies of cognitive training paradigms in mmTBI.

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“…Taking all studies into account, no overall structural abnormalities are apparent for this sample approximately 2.5 years after pediatric concussion. In contrast, other functional abnormalities, such as alterations in cerebral blood flow, 38 functional connectivity, 39 and N -acetyl-aspartate, 40 were still apparent at this time point in the same sample. Taken together, these results suggest the possibility of persistent functional but not structural alterations in the brain years after concussion.…”

Section: Discussionmentioning

confidence: 76%

Susceptibility-Weighted Magnetic Resonance Imaging (MRI) of Microbleeds in Pediatric Concussion

et al. 2021

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Objective: The long-term consequences of pediatric concussion on brain structure are poorly understood. This study aimed to evaluate the presence and clinical significance of cerebral microbleeds several years after pediatric concussion. Methods: Children and adolescents 8-19 years of age with either a history of concussion (n = 35), or orthopedic injury (n = 20) participated. Mean time since injury for the sample was 30.4 months (SD = 19.6). Participants underwent susceptibility-weighted imaging, rated their depression and postconcussion symptoms, and completed cognitive testing. Parents of participants also completed symptom ratings for their child. Hypointensities in susceptibility-weighted images indicative of cerebral microbleeds were calculated as a measure of hypointensity burden. Results: Hypointensity burden did not differ significantly between participants with a history of concussion and those with a history of orthopedic injury. Depression ratings (self and parent report), postconcussion symptom ratings (self and parent report), and cognitive performance did not significantly correlate with hypointensity burden in the concussion group. Conclusions: These findings suggest that at approximately 2.5 years postinjury, children and adolescents with prior concussion do not have a greater amount of cerebral microbleeds compared to those with orthopedic injury. Future research should use longitudinal study designs and investigate children with persistent postconcussive symptoms to gain better insight into the long-term effects of concussion on cerebral microbleeds.

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Cerebral blood flow in children and adolescents several years after concussion

Cited by 24 publications

References 37 publications

Cerebrovascular Neuroprotection after Acute Concussion in Adolescents

Cerebrovascular Neuroprotection after Acute Concussion in Adolescents

Cerebral Perfusion Effects of Cognitive Training and Transcranial Direct Current Stimulation in Mild-Moderate TBI

Susceptibility-Weighted Magnetic Resonance Imaging (MRI) of Microbleeds in Pediatric Concussion

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