I just read your response to someone else who's friend was diagnosed with this disease - but - I have a sister that is 62 yrs. old and about 6 mo. ago began having slurred speech. She is a very active person and this seems to be the only sympton. She has been to doctor after doctor and this diagnosis was one possibility. When do doctors know for certain that this is the cause of her slurred speech? And why haven't all these specialist been able to definetely tell her what is going on?