Non-vocal stutters?

Non-vocal stutters? I've noticed a lot that, well yes I stutter and have for my entire life, and all the same I've noticed something else. When I write, and have to write quickly, especially when starting a sentence I get a small block on my hand, and might draw the same line several times before writing the word and sentence, I've never noticed this for anyone else. Is this related to stuttering or just me not being a fluid writer? I'd like to hear everyone's thoughts.