The USL / NFHS produced video of 2012 Rules Interpretation is here.
The video embedded below was produced by USL and NFHS in 2011. Those groups are attempting to eliminate contact to the head in lacrosse by redefining the current rules slightly and strongly encouraging more 2 and 3 minute non-releasable personal fouls for contact with and to the head. This doesn't affect slashing, just body checking and cross checking. Although it should be noted that any stick contact with the helmet is a slash in youth play. There is no "just a brush" non-call at these levels.