Hasan is charged with 13 counts of premeditated murder and 32 counts of attempted murder during a shooting rampage at the base in November 2009.
Presiding Judge Col. Tara Osborn ruled the presentations Hasan made while in medical residency and in fellowship years before the shooting were too far removed from the actual incident to be considered.
"It is too remote in time and too open to multiple interpretations," Osborn said of presentations Hasan made while at Walter Reed Military Medical Center in Washington, D.C.
Internet searches and more recent portions of Hasan's web history will be admissible, the judge ruled.
She also ruled out any evidence framing the mass shooting as a "copycat" crime similar to that of former Army Sgt. Hasan Akbar's 2003 attack in Kuwait that killed two and wounded 14.
Akbar is the last member of the Army to be sentenced to death, and was prosecuted by Col. Mike Mulligan, who is the lead prosecutor in the Hasan case, the Killeen, Texas, Daily Herald reported Monday.