Defense attorney James Connell said the revelation was only the second declassified fact the military had released about his client, Ammar al-Baluchi, Courthouse News Service reported Wednesday.
The first declassified fact, Connell said, was that the character "Ammar" in the film "Zero Dark Thirty" was based on his client.
Attorneys for the defendants are trying to get access to information that might confirm they were abused during interrogations by U.S. security agencies. They have been thwarted by a rule that their clients' memories of the interrogation are classified information.
Connell showed judge Col. James Pohl a document Tuesday he said showed al-Baluchi told doctors he suffered memory loss, hallucinations and delusions from a head injury he received before 2006 during a three-year period he was held in secret prisons overseas.
Al-Baluchi and the other defendants should not be able to share "sensitive sources and methods" they were "exposed to" during CIA custody, prosecutor Clay Trivett argued.
Cmdr. Walter Ruiz, who is representing Mustafa al-Hawsawi, said the "sources and methods" Trivett referred to were those banned by the Convention against Torture the United States signed in 1994.