Cerebrovascular Reactivity Impairment after Sport-Induced Concussion

Len, Trevor K; Neary, J. Patrick; Asmundson, Gordon J. G.; Goodman, David; Björnson, Bruce; Bhambhani, Yagesh

doi:10.1249/mss.0b013e3182249539

Cited by 121 publications

(112 citation statements)

References 40 publications

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“…22,54 Even after symptom resolution, neurons under a state of physiologic stress function abnormally and may remain susceptible to second injury. 55,56 Supporting this notion, our recent studies indicate that abnormalities on advanced electrophysiological testing and working memory functional MRI are detectable in athletes who otherwise report a complete symptom recovery and perform normally on clinical measures (i.e., cognitive and balance testing) after SRC. 7,57,58 These findings fuel the critical concern that a window of cerebral vulnerability (WoCV) extends beyond the point of clinical recovery after SRC, when the brain remains physiologically compromised and at heightened risk of repetitive injury.…”

Section: Discussionmentioning

confidence: 88%

Cerebral Blood Flow Alterations in Acute Sport-Related Concussion

Wang

Nelson

LaRoche

et al. 2016

Journal of Neurotrauma

151

127

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Sport-related concussion (SRC) is a major health problem, affecting millions of athletes each year. While the clinical effects of SRC (e.g., symptoms and functional impairments) typically resolve within several days, increasing evidence suggests persistent neurophysiological abnormalities beyond the point of clinical recovery after injury. This study aimed to evaluate cerebral blood flow (CBF) changes in acute SRC, as measured using advanced arterial spin labeling (ASL) magnetic resonance imaging (MRI). We compared CBF maps assessed in 18 concussed football players (age, 17.8 -1.5 years) obtained within 24 h and at 8 days after injury with a control group of 19 matched non-concussed football players. While the control group did not show any changes in CBF between the two time-points, concussed athletes demonstrated a significant decrease in CBF at 8 days relative to within 24 h. Scores on the clinical symptom (Sport Concussion Assessment Tool 3, SCAT3) and cognitive measures (Standardized Assessment of Concussion [SAC]) demonstrated significant impairment (vs. pre-season baseline levels) at 24 h (SCAT, p < 0.0001; SAC, p < 0.01) but returned to baseline levels at 8 days. Two additional computerized neurocognitive tests, the Automated Neuropsychological Assessment Metrics and Immediate Post-Concussion and Cognitive Testing, showed a similar pattern of changes. These data support the hypothesis that physiological changes persist beyond the point of clinical recovery after SRC. Our results also indicate that advanced ASL MRI methods might be useful for detecting and tracking the longitudinal course of underlying neurophysiological recovery from concussion.

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Section: Discussionmentioning

confidence: 88%

Cerebral Blood Flow Alterations in Acute Sport-Related Concussion

Wang

Nelson

LaRoche

et al. 2016

Journal of Neurotrauma

151

127

View full text Add to dashboard Cite

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“…The pathophysiology of mTBI during the acute phase of injury is becoming increasingly well-known suggesting ion imbalance, metabolic disruptions, blood flow abnormalities and autonomic nervous system (ANS) dysfunction as the main culprits [6,[10][11][12][13][14]. When attempting to search for potential mechanisms surrounding PCS; however, findings have been inconsistent and there remains no clear physiologic explanation for this disorder [9,15].…”

Section: Introductionmentioning

confidence: 99%

The role of the cervical spine in post-concussion syndrome

Marshall

Vernon

Leddy

et al. 2015

The Physician and Sportsmedicine

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While much is known regarding the pathophysiology surrounding concussion injuries in the acute phase, there is little evidence to support many of the theorized etiologies to post-concussion syndrome (PCS); the chronic phase of concussion occurring in ∼ 10-15% of concussed patients. This paper reviews the existing literature surrounding the numerous proposed theories of PCS and introduces another potential, and very treatable, cause of this chronic condition; cervical spine dysfunction due to concomitant whiplash-type injury. We also discuss a short case-series of five patients with diagnosed PCS having very favorable outcomes following various treatment and rehabilitative techniques aimed at restoring cervical spine function.

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“…Considering PCS, which by definition lacks gross structural injury, the observed BOLD abnormalities are more likely a result of dysfunctional NVC rather than dysfunctional neural activation and likely the predominant source of its symptoms. Further recent studies confirm a central role of NVC disruption in PCS [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 64%

“…Vasoactive stimuli include CO 2 inhalation, breath holding, hyperventilation and acetazolamide, all of which have the goal of artificially manipulating PaCO 2 in order to observe a passive dilatory response [20]. Commonly used neuroimaging techniques to measure the effects of these vasoactive stimuli include positron-emission tomography (PET), single photon emission computerized tomography (SPECT), XeCT, transcranial Doppler ultrasonography and non-invasive MRI sequencing such as BOLD and ASL.…”

Section: Cerebrovascular Reactivitymentioning

confidence: 99%

Neurovascular Coupling: A Unifying Theory for Post-Concussion Syndrome Treatment and Functional Neuroimaging

Ct¹,

Allen²

2017

J Neurol Neurophysiol

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Post-concussion syndrome (PCS) occurs in a significant percentage of concussion patients and is defined as having a history of traumatic brain injury with persistence of three or more symptoms. Standard structural clinical neuroimaging studies show no abnormal findings for the majority of PCS patients as opposed to functional MRI, which often reveals irregularities in the blood-oxygen level dependent (BOLD) signal. This suggests that dysregulation of neurovascular coupling, which causes abnormal BOLD signals, plays a significant role in PCS pathology. However, compared to the pathophysiologic mechanisms occurring in acute concussion, the underlying neuropathophysiology of chronic concussive sequelaeor PCS is less understood, though becoming clearer with emerging research. We present a treatment approach grounded in the physiological theory presented here called Enhanced Performance in Cognition (EPIC), which has shown strong clinical success. Dysregulation of neurovascular coupling (NVC), along with disruptions in cerebrovascular reactivity (CVR) and autonomic nervous system (ANS) dysregulation are the targets of EPIC treatment. Success of the approach itself tentatively supports the hypothesis that these three features figure prominently in the neuropathophysiology of PCS. The aim of this report is to provide a theory of the underlying mechanisms of PCS pathology and its treatment that is in accord with the current corpus of research and explains the recent therapeutic success seen in PCS patient using the EPIC treatment. We propose a novel theory concerning the mechanisms by which NVC dysregulation is normalized. This includes focused, intense and repetitive neurocognitive challenges during post-exercise cognitive boost and the avoidance of intracerebral steal in the setting of restored and re-regulated CVR and ANS. It is intended that both the theory and treatment approach are presented explicitly enough to generate empirical studies with clear hypothetical predictions from the theory as well as clinical innovations with significant relevance to improve current practices.

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Cerebrovascular Reactivity Impairment after Sport-Induced Concussion

Cited by 121 publications

References 40 publications

Cerebral Blood Flow Alterations in Acute Sport-Related Concussion

Cerebral Blood Flow Alterations in Acute Sport-Related Concussion

The role of the cervical spine in post-concussion syndrome

Neurovascular Coupling: A Unifying Theory for Post-Concussion Syndrome Treatment and Functional Neuroimaging

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