title: A definition of "on": patient diaries compared to the UPDRS.
abstract: This study investigates the relationship of the Unified Parkinson's Disease Rating Scale (UPDRS) to the patient's perception that they are "on". Following the first dose of medication, patients reported that they were "on" when their UPDRS-III reached a mean of 8+/-2, representing a decrease of 67+/-8% from their early morning rating. Patients reported that they were "off" when their UPDRS-III score increased to 20+/-5, representing an increase of 50+/-12% from their initial "on" score. A 67% improvement in the baseline UPDRS-III score may be useful in defining "on".
authors.affiliation: The Movement Disorders Clinic, Vanderbilt University Medical Center, 2100 Pierce Avenue, Suite 352, Nashville, TN 37212-3375, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Charles
authors.forename: G J
authors.initials: GJ
authors.lastname: Esper
authors.forename: T L
authors.initials: TL
authors.lastname: Davis