Friday, May 22, 2015

Concussions Linked to Brain Atrophy

Permanent brain damage, such as brain atrophy, is the fear post concussions.  More and more studies are showing changes in the brain post concussion especially as our imaging becomes better.  What should we be fearing?  Do we need to fear every concussion?  The good news is that many people with multiple concussions have no brain damage on advanced scans.  The other good news is that people with brain damage are showing improvements in brain scan 2-5 years post concussion.

So what damage do we fear?  Atrophy from other studies has been a permenant change in those older than 30.  Research studies that look for atrophy are more interesting for this reason. Several articles have come out in the past month about the use of imaging.  The goal is to see if imaging can tell us if we are going to have cognitive problems in the future.   Is there are correlation between neuropsych testing and brain atrophy?  I reviewed 2 articles that speak to this.  These articles look at people in there fifties who had mild traumatic brain injury playing college or professional sports.   The first article found that there was no deficits in cognition, but there was clear loss in brain size between the controls and the athletes with concussion.  The 2nd study looked at NFL players who had minor concussion and more serious concussion with loss of consciousness.   Those with LOC (loss of consciousness) were much more likely to have brain atrophy than those that did not.

It is important to understand that none of these individuals likely did not have any treatment beyond 48 hours of rest as this was the standard of care.  We know that exertion can decrease blood flow and likely increased the probability of brain changes.   Seven to ten days without extreme exertion is likely to lessen likelihood of brain atrophy.  The understand of what the atrophy means is still evolving. 

1. Front Aging Neurosci. 2013; 5: 41. Published online 2013 Aug 22. doi:   History of mild traumatic brain injury is associated with deficits in relational memory, reduced hippocampal volume, and less neural activity later in life Jim M. Monti,1,2,* Michelle W. Voss,3 Ari Pence,2 Edward McAuley,2,4 Arthur F. Kramer,1,2,5 andNeal J. Cohen1,2,5

The first study enrolled 20 young-to-middle-aged subjects, who reported two or more sports-related mild TBIs, with the last mildvTBI > 6 months prior to study enrolment (mTBI group), and 21 age-, sex- and education matched controls with no history of mTBI (control group). 

Our data suggest that recurrent mTBIs exerts detrimental effects on cognitive function and cortical thickness in the chronic phase in young-to-middle-aged adults. Specifically, cognitive testing revealed small but consistent deteriorations in cognitive scores, most pronounced for verbal fluency, in the chronic phase after mTBIs.. Moreover, we found that subjects with recurrent mTBIs showed dose-dependent cortical thinning within right temporal lobe and bilateral insula, as compared to subjects without history of mTBI.

2.   2015 May 18. doi: 10.1001/jamaneurol.2015.0206.  Imaging Correlates of Memory and Concussion History in Retired National Football League Athletes.

Participants included 28 retired National Football League athletes, 8 of whom had MCI and a history of concussion, 21 cognitively healthy control participants, and 6 control participants with MCI without concussion.

Athletes with a history of G3 concussion were more likely to have Mild cognitive impairment (MCI) (7 of 7) compared with retired athletes without a history of G3 concussion (1 of 5) older than 63 years (P = .01). In addition, the left hippocampal volume in retired athletes with MCI and concussion was significantly smaller compared with control participants with MCI (P = .03).