Doctors at the Veterans Affairs Medical Center in Bedford, Mass., 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. indicate that those men did not have A.L.S. at all. They had a different fatal disease, doctors said, caused by concussionlike trauma, that erodes the central nervous system in similar ways…

The finding’s relevance to Gehrig is less clear. But the Yankee legend had a well-documented history of significant concussions on the baseball field, and perhaps others sustained as a battering-ram football halfback in high school and at Columbia University. Given that, it’s possible that Gehrig’s renowned commitment to playing through injuries like concussions, which resulted in his legendary streak of playing in 2,130 consecutive games over 14 years, could have led to his condition.