There is no current evidence that taking sinemet speeds up neuronal loss. Theree is some evidence that delaying the use of sinemet may delay the onset of motor fluctuations. We wish to study this further ,however, and there may be more information about the best course to take after a study has been done. In the meantime, all PD experts agree that sinemt should be used when symptoms interfere with one's life. I tend to use sinemet much earlier in the older patient,in whom I am less concerned about very long term fluctuations .I hope this is helpful.