When is a difference a disability? (Part 1)

Dean Zimmer may not be a household name, but he is a great rock and roll drummer.  His drumming style is tight, passionate and musical, and apparently his band has opened for Foghat, Eddie Money, Paul Rogers, Styx, Kansas and Thin Lizzy.  He also has a physical condition that some would call a disability.  Watch him play in this 6-minute documentary, "Drummer Wanted," and see whether or not you would classify him as person with a disability:

 

"He is not handicapped - he is different," 

says his bandmate Rick Abbott.  Dean certainly is different from most drummers.  He holds the sticks differently and has them strapped to his arms.  He moves his body a lot more while playing, rather than just moving his arms and legs.  According to Rick, Dean's limitations contribute to his unique sound.  But is his condition a handicap?  According to the Oxford Dictionaries website definition,

a handicap is "a condition that markedly restricts a person’s ability to function physically, mentally, or socially."  

Is Dean's functioning markedly restricted?  It sure doesn't stop him from playing the drums!  Yes, Dean uses a wheelchair to get around much of the time.  According to The Los Angeles Times, he has a rare congenital disorder called arthrogryposis that makes it difficult to move his joints.  In the video, however, we see Dean driving, climbing, moving around and setting up his drum kit.  Rick claims that Dean can do anything anyone else can do, although it sometimes takes him longer.  I must admit that I had some difficulty understanding some of what Dean was saying at first, but I was able to understand him pretty well on second listen.

Does any of that meet the definition of handicapped?