A new study published February 16, 2022 by the American Academy of Neurology in the Journal “Neurology” finds that the frequency of clinically meaningful poor cognitive outcomes one year after a concussion are more common than previously thought.  The results, says study author Raquel Gardner, MD, of the University of California San Francisco, “highlight the need to better understand the mechanisms underlying poor cognitive outcome, even after relatively mild brain injuries, to improve therapy for recovery.”
This large “TRACK-TBI” study looked at 656 people admitted to trauma center emergency rooms with concussions and a control group of 156 health people without head injuries. The researcher found that 14% of the concussion group had poor cognitive outcomes one year after their concussion (defined as lower than expected performance on at least two cognitive tests.) The domains of memory and processing speed were most affected at one-year post injury.

As referenced in the publication, the study was prompted in part by evidence from a systematic review published in 2017 in PLOS One by McInnes, et.al.,  that half of individuals with mild traumatic brain injury (mTBI) experience cognitive impairment on neuropsychological assessment at 3 months, 6 months or 12 month post-injury “refuting the long-held belief that the vast majority of patients with mTBI experience complete recovery 34 months post-injury.”

Among the predictors of poor cognitive outcome identified in the TRACK-TBI study were a history of depression as well as low income and lack of health insurance. (We have discussed the research on why depression can be a predictor of poor outcomes in prior blog posts.)

A surprising but encouraging finding in this study was that otherwise healthy older adult survivors of mTBI may achieve equally good cognitive recovery as younger adult survivors of mTBI.