A peer-reviewed paper to be published Wednesday in a leading journal of neuropathology, however, suggests that the demise of athletes like Lou Gehrig and soldiers given a diagnosis of amyotrophic lateral sclerosis, commonly known as Lou Gehrig’s disease, might have been catalyzed by injuries only now becoming understood: concussions and other brain trauma. Although the paper does not discuss Gehrig specifically, its authors in interviews acknowledged the clear implication: Lou Gehrig might not have had Lou Gehrig’s disease. Doctors at the Veterans Affairs Medical Center in Bedford, MA, and the Boston University School of Medicine, the primary researchers of brain damage among deceased National Football League players, said that markings in the spinal cords of two players and one boxer who also received a diagnosis of A.L.S. indicated that those men did not have A.L.S. They had a different fatal disease, doctors said, caused by concussionlike trauma, that erodes the central nervous system in similar ways.