TBI for Dummies, the research pt 1

Multiple concussions can cause cumulative damage

Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA Concussion Study. 2003
Guskiewicz KM, McCrea M, Marshall SW, Cantu RC, Randolph C, Barr W, Onate JA, Kelly JP.
"Our study suggests that players with a history of previous concussions are more likely to have future concussive injuries than those with no history; 1 in 15 players with a concussion may have additional concussions in the same playing season; and previous concussions may be associated with slower recovery of neurological function."
Departments of Exercise and Sport Science, University of North Carolina at Chapel Hill, 27599, USA
http://www.ncbi.nlm.nih.gov/pubmed/14625331

Cumulative effects of concussion in amateur athletes. 2004
Iverson GL, Gaetz M, Lovell MR, Collins MW.
"There were differences between groups in symptom reporting and memory performance. At baseline (i.e. preseason), athletes with multiple concussions reported more symptoms than athletes with no history of concussion. At approximately 2 days post-injury, athletes with multiple concussions scored significantly lower on memory testing than athletes with a single concussion. Athletes with multiple concussions were 7.7 times more likely to demonstrate a major drop in memory perfomance than athletes with no previous concussions."
Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
http://www.ncbi.nlm.nih.gov/pubmed/15195792



TBI can be degenerative

Inflammation and white matter degeneration persist for years after a single traumatic brain injury. 2013
Johnson VE, Stewart JE, Begbie FD, Trojanowski JQ, Smith DH, Stewart W.
"These data present striking evidence of persistent inflammation and ongoing white matter degeneration for many years after just a single traumatic brain injury in humans. "
Penn Centre for Brain Injury and Repair and Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
http://www.ncbi.nlm.nih.gov/pubmed/23365092