I have similar problems not only in my sight-reading, but also in reading
out loud, especially in a foreign language.  All this on top of being an
occasional stutterer.  Although I haven't completely eradicated my stammer,
I have ways of combating it and I seem to understand where it's coming
from.  Approach it from both a pedagogical and psychological standpoint.

Pedagogical:  Force yourself to move on.  Teach yourself to look ahead
of where you're playing when you're sight reading.  Be conscious of hand
preparation.  If the music permits, move your hands to the next chord/notes
as soon as possible so you won't have the chance to "stammer." Also, sight
read without stopping.  If you stop, you're not sight reading, you're
practicing.  What's the worst thing that can happen to you if you screw up?
Make this a new habit.

Psychological:  The bigger problem is that one's mind isn't clear.  If your
mind's cluttered up, you're bound to make mistakes.  I meditate frequently
and try to bring that to my playing.  Also, relax and remember to breath
naturally.  Any tightness, restriction of blood/oxygen flow will impair
your judgements.  Mistakes will be inevitable.  Don't react to them or
linger in them.  Once that moment has past, just accept that it's in the
past and you can't change it.

This was just a short overview of my approach.  It seems to help me.
E-mail me if you have any more questions.  I feel for you man.

Bob Yoon
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