Was on an icy cat-track, slightly downhill facing maybe 15 degree pitch, around 3 mph. Turned to see where my wife was and then I was looking straight up at the sky. Giro 9 dented-head not. Brain no more scambled than usual.
Wear a helmet, please.
A concussion, even slight, will affect your coordination for a week or more, so stay away from those activities that require it.