Resting Cerebral Blood Flow Immediately Post Concussion is correlated to Cognitive Performance

Abstract

Sports related concussion is estimated to affect more than 3.8 million Americans a year. Despite the large number of concussions, our understanding of the mechanisms underlying concussion are limited. We also lack an accurate diagnostic tool to provide an indication of concussion severity. Currently, most concussion assessments use cognitive testing to assess severity. Our lab has been examining use of Doppler ultrasound in the field as a possible novel objective measures of concussion severity. We recruited players from recreational rugby tournaments. Players who were seen at the medical tent and determined not to need further treatment were offered the opportunity to participate. A control group of players who had played a rugby match but did not receive a head hit were also recruited. During the tournaments, we used a portable tent based lab to obtain measures of internal carotid cerebral blood flow by imaging the artery to obtain diameter and velocity. Additionally, we measured both beat‐by‐beat blood pressure (Finometer) as well as end tidal CO2 using a nasal cannula during rest, both in the seated and supine position. In a subgroup of 47 players (28 controls, 19 concussed, Mean age= 30, range= 19–66 yrs) out of our large study (125 players, 49 concussed), we had players perform a Simple Reaction Time Test (SRTT), Trails A & B, Digit Symbol Substitution Test (DSST), Paced Auditory Serial Addition Test (PASAT) with 3 sec and 2 sec delay and a Digit Span Memory Test. Concussed players had significantly higher SCAT total number of symptoms (15 ± 11 vs 5 ± 7, P=0.029) as well as Symptom Severity Score (33 ± 18 vs 7 ± 9, P=0.002). Concussed players only performed significantly worse on the SRTT (353 ± 128 ms vs 278 ± 44 ms, P=0.046) while trending on DSST (54 ± 15 ms vs 63± 4 ms, P=0.085). Concussed players demonstrated significantly greater cerebral blood flow when seated (646 ± 180 mL/min vs 415 ± 85 mL/min, P=0.001). Cerebral blood flow was also significantly correlated to performance on SRTT (r=0.84, P=0.035), Trails B Time (r=0.94, P=0.006), DSST (r=−0.88, P=0.021) and Digit Span (r=−0.89, P=0.019). Surprisingly increased seated cerebral blood flow was found in the concussed players and associated with worse cognitive performance. This initial study suggests that cerebral blood flow immediately post‐concussion may be an objective indicator of severity. Future work is needed to examine how immediate measures of cerebral blood flow are predictive of cognitive recovery and post‐concussive symptoms.Support or Funding InformationThis work was supported by Dept. of Pharmacology, Physiology, and Neuroscience, Rutgers and the War Related Illness and Injury Study Center.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.