According to the June 1st issue of the New York Times:
"A new study may help explain why some military personnel exposed to blasts have symptoms of brain injury even though their CT and M.R.I. scans look normal...
Read the story at http://www.nytimes.com/2011/06/02/health/02brain.html?ref=health
Phylis Feiner Johnson www.epilepsytalk.com