Up here in New England at Mass General Hosp. the doctor I saw talked about a ALS continuum. With UMN/LMN ALS on one end and UMN dominate ALS followed by PLS on the other end. It is all MND, my understanding is some doctors do not follow this logic and consider them there own conditions. Sorry typing is not going well tonight. We had a thread on the PLS page that talked about this have you seen it. Believe it was in DEC. 13. Hope this answers your question