Welcome, Patti. If your husband has been receiving PD care from a neurologist for the past 17 yrs, I would say it is highly unlikely that he has been misdiagnosed. The doc(s) knows exactly what to look for as time goes by. Your husband's symptoms may "appear" to improve as he backs off certain meds, but this may simply be a temporary result of "not" taking the meds--if that makes any sense. Most every PD patient will or should take a brief "holiday" from taking sinemet, for example. I have had PD for about 17 yrs; onset of symptoms at age 34. I "feel" better for a few days when I take a 5-7 day break from the sinemet, but it is kind of risky business.