NHL commissioner Gary Bettman has once again maintained that there is not enough data yet to draw conclusions about the link between sports-related concussions and long-term brain degeneration.

This came in a 24-page letter Bettman wrote to U.S. Senator Richard Blumenthal that was posted on The New York Times' website Tuesday night, answering a series of questions put to him by the Connecticut Democrat on the NHL's stance on concussions and the brain disease chronic traumatic encephelopathy (CTE).