Clueless Allison

I know it's not nice to say someone is clueless, but if anyone spends more than five minutes with my #5 child you would know what I'm talking about.    Allison is very gifted in many areas.  She is a phenomenal artist.  Ally also has a creative writing ability.   However, when a person talks to Allison, one gets a sense that she isn't exactly following you at the same speed.  It isn't that she is mentally challenged, don't get me wrong. What it is, is just a stereotypical blonde airhead.  On more than one occasion a person has been talking to Ally and she is laughing and one would assume she is following, but half way through the convo Ally goes "uh, what, wait.......  huh?" and you can't help but laugh because her expression goes from laughing to complete cluelessness in seconds.  
Unfortunately this has gotten her hurt on a couple occasions.  There was one time in particular that was memorable.   Allison was probably about five and  she and Jacob went out sledding.  We had a tremendously long hill and it made a perfect place for sledding.  Well, Jake and Ally piled in the sled and headed down the hill.  About half way down Jake realized they were heading towards a tree so he told Ally to bail out and then did the same.  Allison either didn't hear the 'bail out' part, or just didn't get it because she stayed on the sled.  Jake started running after her screaming, "jump off Ally, bail out" to no avail.  Ally simply turned around and looked at Jake, smiled and waved, completely oblivious to the tree looming in the distance.  Well, you guessed it, she hit the tree.  To make a long story short, we took her to the doctor and they thought she broke her leg but ended up taking the cast off after two weeks because they decided she hadn't.  I'm not so sure she didn't break something though because she still runs with a distinct limp.  However, she just keeps smiling and waving with that clueless expression on her face.