LONG-DURATION RESPONSE TO LEVODOPA

We measured the long-duration response to levodopa by changes in tappi ng rate in 16 patients with Parkinson's disease undergoing 3 to 5 days of levodopa withdrawal. ''Off' tapping rates deteriorated 22% over th e course of this holiday, the decline beginning 24 hours after levodop a withdrawal. Deterioration was more pronounced in the more affected h and in asymmetrically affected patients. A 2-hour infusion of levodopa after the levodopa holiday did not restore the long-duration response , although it produced a greater short-duration response than before t he holiday. These observations indicate that the long-duration respons e is an important component of the therapeutic benefit of levodopa and is separable from the short-duration response.