My husband has had mumbly speech for 3 years. No abnormalities in brain scan. His tongue and lips do not move normally when speaking mumbly. Was checked for Guillian Barre. Also has had double vision for as long. Has had diabetes for probably 20 years, and high blood pressure for 35 to 40 years both being treated with medications. Is 74 yrs. Old now. What could be the cause of mumbly speech and of double vision? Doctors do not seem to put together. At time of speech problems commencing he had been prescribed doxazosin double what he had been taking. Then was taken off of that and given something else. We wondered if this medication could have caused mumbly speech.