Cluttering is often thought of as being similar to stuttering. I'm not convinced that this is the case. Both are disorders of fluency, but the differences between the two are quite marked. There is a new association of cluttering, the International Cluttering Association, which has a lot of very good information about cuttering.

There is also an excellent article about cluttering on the ASHA web site,
Cluttering Updated, written by leading experts in the field, Ken St. Louis, Lawrence Raphael, Florence Myers & Klaas Bakker.