Concussion Recovery Time Indicated by Cerebral Blood Flow

Cerebral blood flow (CBF) recovery in the brain could be indicative of outcomes in patients after concussions, according to findings published in JAMA Neurology.

Researchers from the Mind Research Network/ Lovelace Biomedical and Environmental Research Institute in Albuquerque studied 44 collegiate football players in a longitudinal and cross sectional study which ran from March 2012 and December 2013.

A portion of the athletes who had concussions (17 participants) underwent serial imaging occurring about 1 day, 1 month, and 1 month post concussion in order to assess the recovery of CBF and compare time course of CBF recovery with that of cognitive and behavioral symptoms.

There were no significant age differences among injured and uninjured participants, though the researchers observed the trend of concussed athletes self reporting more previously diagnosed concussions than non concussed athletes.

The researchers determined that the athletes’ cognitive and neuropsychiatric symptoms observed at 1 day post concussion were resolved by the time 1 week or 1 month post concussion. The imaging analysis revealed CBF recovery in parts of the brain and that CBF in the dorsal midinsular cortex was decreased at 1 month post concussion in slower to recover athletes and in athletes with the most severe initial psychiatric symptoms.

One of the benefits in this study design, noted the authors, was that it eliminated the possibility of data corrupted by sex, age, and exercise induced cardiovascular changes, because the participants were all athletes. This allowed the investigators to focus solely on the participants’ concussion recovery.

The athletes who demonstrated poor outcomes — which were determined by the researchers – had more severe depression and anxiety scores at each follow up point during the investigation. The authors believed this would have been even more significant in a larger cohort. The scores for depression and anxiety also impacted the recovery curve, which could have been affected by factors like temporal differences, a desire to return to play, the emotional symptoms of concussion, or clinician rater bias in the non blind assessment.

“Return to play decisions are currently based on clinical judgment that is informed by neurocognitive batteries and self report symptom metrics rather than on evidence based biomarkers,” the authors wrote. “Although evidence suggests that other physiological consequences of concussion might extend beyond typical symptom resolution, these results suggest a potential temporal relationship between the timeframe of CBF recovery and the resolution of symptoms previously reported.”

This research contributed to the current literature in that locations of CBF abnormalities were pinpointed and future studies may not want to use blood oxygen level dependent imaging to determine various facts about each individual concussion.

“This data demonstrated that the acute and subacute phases of sports related concussion are associated with perfusion deficits that show both longitudinal and cross sectional evidence of recovery,” the authors concluded.