@article{ref1,
title="Impaired cerebral vasoreactivity despite symptom resolution in sports-related concussion",
journal="Journal of neurotrauma",
year="2019",
author="Purkayastha, Sushmita and Sorond, Farzaneh A. and Lyng, Sydney and Frantz, Justin and Murphy, Megan N. and Hynan, Linda S. and Sabo, Tonia and Bell, Kathleen",
volume="36",
number="16",
pages="2385-2390",
abstract="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 play 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) following 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), sub-acute 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 vs.12.1±7; P<0.0001) and severity (4.2±6 vs. 29.5±23; P<0.0001), higher Patient Health Questionnaire-9 score (2.2±2 vs. 9.1±6; 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 three 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.<p /> <p>Language: en</p>",
language="en",
issn="0897-7151",
doi="10.1089/neu.2018.5861",
url="http://dx.doi.org/10.1089/neu.2018.5861"
}