The NBA distributed a video starring Vice President of Referee Operations Joe Borgia discussing the league's "points of emphasis" for the 2014 playoffs.
Things get pretty serious at about 13 minutes in, when Borgia says "we noticed this season there was a lot more contact to opponents' heads ... this is a very dangerous situation." Then Borgia rolls a clip of a game broadcast in which Hubie Brown expresses dismay at the number of defenders going for the head and neck.
To my eyes, over the last few years defenders do seem to be using blows to the head as a fairly common tactic to prevent layups, even at the exact moment in history medical science and the league itself are putting new emphasis on preventing such dangerous plays.
Basketball doesn't have football's reputation for head injuries, but it does have a certain rate of concussion and head injuries, many of which, by virtue of the fact that they come on intentional fouls to prevent layups, could presumably be prevented.